Man-capable ornithopter?

[ProfessorJoeVee]

Hi everyone! I'm new to the forum here, having finally registered after visiting quite a few times. Let me start by just saying I think this is a really cool forum!

I am interested in hearing what the forum knows about "modern" man-capable ornithopters. Does anyone know if these exist? I think the possibilities are fascinating. Thanks!

[Patricia J B]

Hi everyone! I'm new to the forum here, having finally registered after visiting quite a few times. Let me start by just saying I think this is a really cool forum!

I am interested in hearing what the forum knows about "modern" man-capable ornithopters. Does anyone know if these exist? I think the possibilities are fascinating. Thanks!

Hello Joe,
There are several people around the world currently designing and building manned ornithopters. So far no-one has succeeded in sustaining flight in a manned true ornithopter [ all flapping wing with no fixed wings and no other assist such as jet engines, tow aloft etc]....many people have tried in the past but have not succeeded. Some have succeeded in sustaining flight only with the assistance of fixed wings or auxiallary jet engine etc.

Here's a few URLs for you.

My own website:
http://www.ornithopter-pilot.com

The University Of Toronto website:
http://www.ornithopter.ca

Velko Velkov:
http://www.geocities.com/velkov.geo

Cheers,
Patricia

[Tweener]

This seems to be a good thread to post a question I've had for some time. In the U.S. if you are developing a new experimental aircraft, do you need permission to test it from the FAA? What type of certification does a pilot need in order to test fly it? I'm assuming there is some kind of red tape involved that the Wright brothers didn't have to contend with.

I work at a small airport and have dreamed about throwing my hat in the ring with an ornithopter design I have been thinking about. I don't want to give too many details just yet, but depending on how stringent Patricia's definition is, I may need to call it just an "oscillopter" and let everyone else decide if it fits in the ornithopter group if it ever gets off the ground.

[Patricia J B]

Hi Tweener,

In the US you would need to get in touch with the FAA probably and explain that you are building a new design of homebuilt aircraft. They would then decide if an orni would come under their regulations for homebuilts. You should join the EAA too. At the moment there is no category for ornis in the FAA regulations but they will probably use the precedent set in Canada by Transport Canada Air in their handling of the University Of Toronto ornithopter C-GPTR.
I was the first test pilot of PTR [from 1995 until the end of 2001]......Transport Canada treated it a a homebuilt and it had to be inspected by them throughout the construction to ensure that it met the usual standards [aircraft rated construction materials and building practices]....when it came time to register it on the civil aircraft register, they had to re-instate the old ornithopter category.

Re: Pilot qualifications.
Since there is no orni pilot's licence, Transport Canada gave me an authorisation on my Commercial Pilot's Licence/Aeroplanes to fly it [and any ornithopter] .....so , in Canada anyway, you have to have a pilot's licence.

In my experience, orni's are more difficult to pilot than a fixed wing aircraft and pilot training is necessary.

Re: orni definition.
I didn't invent the definition of orni that I've given above. It's the definition that's been used since the very first orni's were invented.
The U Of Toronto orni was an ornithopter when I was it's pilot but after I left, their new pilot weighed much more than me and they had to add a small set of fixed wings and then an auxilliary jet engine . It's now a hybrid flapping/fixed wing/ jet :)

Here's another URL
[my new ornithopter forum...'.Ornithopter Research Group' ]
http://forums.delphiforums.com/ornithopter/messages

Cheers,
Patricia

[Tweener]

The ideas that I have would probably fit almost in the ultralight category. I know quite a few qualified pilots, but I don't know if any would be willing to be a test pilot. I also know quite a few mechanics, but they would have to be willing to just donate their time to something new and different. I would start with a 1/4 - 1/3 scale RC model, and go from there. This would be a bit like the guy in "The Flight of the Phoenix", who only ever designed models but knew that the same aerodynamic forces apply to a larger scale. ;)

[Patricia J B]

Yes, I'm hoping that my Nightingale orni will come under the 'Ultralight' category too. It's weight certainly is well under the ultralight limits but the regulations are different for ultralights than for regular 'homebuilts'.....Transport Canada may insist on the homebuilt category because of the mandatory inspections during construction that are required for registered homebuilts but not for some ultralights.

These inspections are to ensure that you are using standard aircraft rated materials and building practices . They don't inspect your design itself [unless, of course, it's an obvious deathtrap ! ]

The EAA [Experimental Aircraft Association] is a worldwide association of aircraft homebuilders with local chapters everywhere. Through them, you can learn the different types of construction materials and how to use them eg: wood and fabric, steel tube fuselage, sheet metal, composite construction using fibreglass, carbon, foam epoxy etc. They are also usually the local rep' for homebuilders to the FAA and very often they are designated to conduct the inspections etc. They can tell you what will be required and help you in many ways.

Cheers,
Patricia

[NChronister]

Historically, the term "ornithopter" has been applied to aircraft in which the driving airfoils have an oscillatiing motion, rather than the rotary motion of an airplane propeller or the rotor of a helicopter. In nearly all cases, there is some amount of fixed wing or stabilizer area. Patricia's definition requires the total absence of a lifting stabilizer, even though birds derive a significant amount of lift from the body and tail.

In the past, some people have tried to put a numerical limit on stabilizer area. For example, the Academy of Model Aeronautics in the US limits the stabilizer area to 50% of the flapping area. Such cutoffs may be appropriate for contest rules, but not for definition of a term, because that would create the highly illogical situation of calling two nearly identical aircraft by different names: One has 50% stabilizer and is called an ornithopter. The other has 51% stabilizer and is not called an ornithopter.

Bob Mueser authored the current AMA rules. His goal was to ban models having large fixed wing areas, which had previously been allowed in the contest and historically had been regarded as ornithopters. For example, the Smithsonian Institution calls this machine designed by Lawrence Hargrave an "ornithopter": http://www.centennialofflight.gov/essay/Prehistory/late_1800s/PH4G3.htm

I could also cite a whole bunch of old magazine articles from MAN, Aeromodeller, etc., which illustrate that such models were historically regarded as ornithopters. Patricia Jones-Bowman is now pushing for a more narrow definition of the term, and I predict that in a few decades, someone will come along and once again try to redefine the term "ornithopter" so that it only applies to those machines which have simulated feathers and birdlike articulation of the wings.

Additional problems arise when we consider that the percentage area of the stabilizer does not necessarily indicate the amount of lift it will contribute, the lift contribution may depend on control inputs, etc. Therefore we might not know whether something is an ornithopter, or it could change into an ornithopter at any moment just by tweaking the controls! Clearly this is not an acceptable way to define the term "ornithopter". I have further developed these arguments on my web site: http://www.ornithopter.org/a.fixed.shtml. Anyone interested in this matter is highly encouraged to read these points.

It's questionable too why someone would object to the use of fixed wings anyway. On purely aesthetic grounds, obviously, these machines don't look so much like a real bird, but they do preserve the essential characteristic of natural flight which is the use of an oscillating foil. (Except for some bacterial flagellae nature does not make things that rotate.) Meanwhile very few ornithopters truly imitate bird flight with feathers and all, so if the goal is full replication of bird flight then no machine existing today qualifies as an ornithopter.

And from a functional standpoint, it must be understood that a fixed wing does not support or sustain an aircraft in any way. It is simply a device for converting thrust (from the flappers) into lift. Energy is always LOST in this conversion. A large fixed wing inevitably produces a large amount of drag. If this method of lift production is to be used, then the flapping wings must produce a correspondingly large amount of thrust in order to offset the extra drag of the fixed wing. The design and construction of the ornithopter with a large fixed wing may be easier, because not as much gear reduction is needed, the mechanical loads will be reduced, etc. JUST AS IT IS EASIER not to build an ornithopter with feathers. But the fixed wing does not confer any magical advantage.

Now, since there is no objective or reasonable way to draw a line between ornithopters supposedly assisted by fixed wings, and those merely having a stabilizer, we have to accept those with large fixed wings providing substantial lift as ornithopters as well. And therefore I must give a quick summary of manned ornithopter flights that have used fixed lifting surfaces:

1929. An ornithopter designed by Alexander Lippisch, later famed for his development of the Me-163, was flown a distance of 250-300 meters, assisted by a tow launch. This aircraft had flapping wings hinged at the midline of the fuselage and it also had a lifting stabilizer in the rear. As I said, it was assisted by a tow launch and we don't have enough information to estabilish whether it could maintain equilibrium once launched. The aircraft was powered by the pilot in a rowing-like action. Human muscle can produce about 1 hp only for a very short period, again making it difficult to determine whether Lippsich's flight was losing energy the whole time or was held briefly at equilibrium until the pilot's power output decreased.

1942a. Adalbert Schmid constructed a human-powered ornithopter resembling a sailplane with the addition of small flapping wings in between the main fixed wings and the rear stabilizer. It was flown a distance of 900 meters at constant height after a tow launch to 20 meters. As with Lippisch's 1929 flight, it is impossible to rule out the possibility that the initial velocity from the tow launch was used to maintain height, though Schmid regarded the flight as a complete success.

1942b. Adalbert Schmid's ornithopter was modified by the addition of a motorcycle engine, which allowed fully sustained and controlled flights up to 15 minutes in duration.

1947. Adalbert Schmid successfully flew a second ornithopter. This one was a Grunau Baby IIa sailplane with flapping outer panels added to the wings.

Because of the war and occupation, these events were slow to receive the attention they deserved. However, Schmid's work was described in several German magazines and Bruno Lange's Typenhandbuch des deutschen Luftfahrttechnik.

[ProfessorJoeVee]

Hey, thanks everyone for the great replies and links!

I'm also interested in what the forum knows about ornithopter power sources. What is the most common power source for an RC ornithopter? Also, does anyone know what's the record flight distance for an ornithopter?

[Patricia J B]

Historically, the term "ornithopter" has been
applied to aircraft in which the driving airfoils have an oscillatiing motion, rather than the rotary motion of an airplane propeller or the rotor of a helicopter. In nearly all cases, there is some amount of fixed wing or stabilizer area. Patricia's definition requires the total absence of a lifting stabilizer, even though birds derive a significant amount of lift from the body and tail.

I could also cite a whole bunch of old magazine articles from MAN, Aeromodeller, etc., which illustrate that such models were historically regarded as ornithopters. Patricia Jones-Bowman is now pushing for a more narrow definition of the term, and I predict that in a few decades, someone will come along and once again try to redefine the term "ornithopter" so that it only applies to those machines which have simulated feathers and birdlike articulation of the wings.

Additional problems arise when we consider that the percentage area of the stabilizer does not necessarily indicate the amount of lift it will contribute, the lift contribution may depend on control inputs, etc. Therefore we might not know whether something is an ornithopter, or it could change into an ornithopter at any moment just by tweaking the controls! Clearly this is not an acceptable way to define the term "ornithopter". I have further developed these arguments on my web site: http://www.ornithopter.org/a.fixed.shtml. Anyone interested in this matter is highly encouraged to read these points.

It's questionable too why someone would object to the use of fixed wings anyway. On purely aesthetic grounds, obviously, these machines don't look so much like a real bird, but they do preserve the essential characteristic of natural flight which is the use of an oscillating foil. (Except for some bacterial flagellae nature does not make things that rotate.) Meanwhile very few ornithopters truly imitate bird flight with feathers and all, so if the goal is full replication of bird flight then no machine existing today qualifies as an ornithopter.

And from a functional standpoint, it must be understood that a fixed wing does not support or sustain an aircraft in any way. It is simply a device for converting thrust (from the flappers) into lift. Energy is always LOST in this conversion. A large fixed wing inevitably produces a large amount of drag. If this method of lift production is to be used, then the flapping wings must produce a correspondingly large amount of thrust in order to offset the extra drag of the fixed wing. The design and construction of the ornithopter with a large fixed wing may be easier, because not as much gear reduction is needed, the mechanical loads will be reduced, etc. JUST AS IT IS EASIER not to build an ornithopter with feathers. But the fixed wing does not confer any magical advantage.

Now, since there is no objective or reasonable way to draw a line between ornithopters supposedly assisted by fixed wings, and those merely having a stabilizer, we have to accept those with large fixed wings providing substantial lift as ornithopters as well.

No, the term 'ornithopter' has not "historically been
applied to aircraft in which the driving airfoils have an oscillatiing motion, rather than the rotary motion of an airplane propeller or the rotor of a helicopter." When people were first trying to fly, there were no propellers or helicopters. They watched the birds flying by flapping their wings and they tried to copy that flapping motion, they were human powered machines and they called them 'ornithopters' [bird-like wing] it was bird-like because it flapped NOT because it had feathers. Some of the early ones did try to use feathers but the majority did not. From the very first, the term 'ornithopter' has NOT included fixed wing aircraft. When the first fixed wing aircraft came along, they ceased to be called ornithopters and were named 'aeroplanes' or 'airplanes' [which means heavier- than- air, fixed wing aircraft] . Likewise, when rotary wing aircraft came along, they were not called aeroplanes, they were called helicopters. It's very simple ornithopters = flapping wing, aeroplanes = fixed wing, helicopters = rotary wing. Any of these may have a moving stabilizer on the aft end for stability and control purpose. The direction of the 'lift' of a stab' varies depending on the mode of flight.[ If you were relying on a normal sized movable,rear stab' to provide constant lift in the upward direction, sufficient to sustain flight in addition to providing stability and control you would be disappointed.

A large set of fixed wings in the usual position with a small set of flapping wings at the rear acting to produce thrust [instead of a propeller] is a completely different matter and is quite obviously not a true ornithopter

I have researched many of the early orni patents, some of which have the defintion as part of their introduction, I will look them up and post the links here.

quote from Nathan..." Patricia Jones-Bowman is now pushing for a more narrow definition of the term, and I predict that in a few decades, someone will come along and once again try to redefine the term "ornithopter" so that it only applies to those machines which have simulated feathers and birdlike articulation of the wings...."

I'm not "now pushing' for anything. I'm simply using the term 'ornithopter' in the way that those who invented it intended it to be used and in the way that has been commonly used for 100 years. You have to remember that they had no other reference than the birds. There were no fixed wings, props, rotary wing aircraft or anything else so when they coined the word ornithopter, they couldn't possibly have intended it to include fixed wing combinations, jet engines or anything at all except flapping wings and and all-moving bird style tail.

It is only fairly recently that some people have been trying to stretch the original meaning of ornithopter to ludicrous proportions for various ,highly questionable, reasons . I can't help wondering why they wouldn't want a completely different and new name for their aircraft and why, if they insist on using the term ornithopter, do they object to the term 'hybrid ornithopter' ?
No-one , in all honesty, could possibly claim that Schmid's aircraft with it's large fixed wings and very small aft-mounted flapping wings is the same as an ornithopter which has no fixed wings at all, just flapping wings . The method of flight, the airflow during flight etc etc are completely different in each aircraft.

It is really muddying the waters of scientific research intotrue flapping flight. If an aircraft has both large fixed and small flapping wings and then sustains flight, it certainly can't be claimed that it was a successful true flapping wing flight because if the fixed wings were removed, the aircraft wouldn't even lift off the ground. For those of us who are interested in finally succeeding in sustained flapping flight [I realize not everyone is interested in this] a fixed/flapping wing hybrid flight is of no use at all in our research because it tells us nothing about true flapping flight.....we already know that a fixed wing will sustain flight and it would be impossible to separate the data gathered from each wing as they would interact with eachother.

Patricia

[NChronister]

From the earliest use of the word, these machines with flapping propellers and large fixed wings have consistently been referred to as "ornithopters". That is why I say Patricia is trying to change how the term is being used. Now here is the documentation:

In his 1894 book, Progress in Flying Machines, Octave Chanute doesn't even use the word "ornithopter". Perhaps the term hadn't yet seen wide use. However, Chanute saw fit to place this steam-driven model in the flapping-wings chapter of his book, despite its also having fixed wings:

http://invention.psychology.msstate.edu/i/Chanute/library/photos/Prog_Fig14.gif

Chanute apparently recognized that the actual driving means was more important for classification purposes: "The main portion of the weight was to be sustained [sic]by superposed aeroplanes, and hence the machine should perhaps be described under that head, but it is here included under the head of wings, because of the mode of propulsion."

By the 1930s, the word "ornithopter" was being used, and regardless of any definitions that were put into writing, it is clear from the following articles that the actual useage of the term held no restrictions on fixed-wing lift.

http://www.ornithopter.org/archive/AM53.01.jpg

http://www.ornithopter.org/archive/AM46a.jpg

Here are a few more (slightly more recent) where I decided to include the full image instead of just a link:

http://www.ornithopter.org/ornithbelle.jpg

http://www.ornithopter.org/ornithconover.jpg

Patricia's argument seems to imply that a fixed airfoil either supplies a weak, variable lift force only as needed for stability, or supplies a large lift force that clearly serves as a major source of lift. In fact, there is a continuum between these two states. Many designs will not cleanly fall into one category or the other. Patricia has not yet addressed this fact. It is the inability to objectively categorize different models along this continuum which I feel invalidates Patricia's proposed definition of the term "ornithopter".

IS THIS AN ORNITHOPTER?
http://www.ornithopter.org/parham.jpg

I'd like to refer to a typical indoor contest model designed by Reginald Parham in the 1930s. This design was copied by many others, including Lew Gitlow (Flapping Flyer kit formerly produced by Indoor Model Supply) and Roy White (Rara Avis). After the AMA moved to restrict fixed wing area, this became the standard contest design for a little while, until canard biplanes began to dominate.

Parham's design has a cambered stabilizer. By examining the CG (center of gravity) location, we can conclude that the stabilizer must contribute a significant amount of lift. Was Parham trying to add magical free lift to help his ornithopter fly better? I don't think that is likely. I think it is more likely that he wanted a longer motor stick in order to boost flight times. When you lengthen the motor stick, the weight inevitably shifts onto the stabilizer. This would not obviously be seen as "an airplane with a flapping propeller". Yet this type of model is not a true ornithopter according to Patricia.

Hargrave, Schmid, and others who have used particularly large fixed wings, probably did so NOT in an effort to get FREE LIFT. These were smart people who knew that wings would also add DRAG to their aircraft. Rather, there were other PRACTICAL reasons for the size of the fixed wings. Generally this is done when you don't have enough gear reduction to flap larger wings.

Any flapping wing has its greatest vertical motion at the outer end. At the hinge point, there is no vertical motion relative to the ornithopter body. The inner part of the wing has a much smaller vertical motion than the outer part, and it functions pretty much like a fixed wing. So even if you eliminate all "fixed" lifting area from your ornithopter, the machine will still derive MOST of its lift by that same principle. The only way to avoid this would be to plunge the entire wing straight up and down (rather than hinging at the shoulder) and that is decidedly un-bird-like.

[Patricia J B]

This is an exerpt from the book ' Flying Machines: Construction And Operation ' by W.J Jackman and Thomas H Russell published in 1912. The introductory chapter was written by Octave Chanute who also gave assistance with the other chapters in the book [ The authors state that this was the last aviation related activity that Chanute did before he died in 1910 ]

Here's the exerpt:
quote:
".....CHAPTER IV.

VARIOUS FORMS OF FLYING MACHINES.

There are three distinct and radically different forms
of flying machines. These are:

Aeroplanes, helicopters and ornithopers.

Of these the aeroplane takes precedence and is used
almost exclusively by successful aviators, the helicopters
and ornithopers having been tried and found lacking in
some vital features, while at the same time in some
respects the helicopter has advantages not found in the
aeroplane.

What the Helicopter Is.

The helicopter gets its name from being fitted with
vertical propellers or helices (see illustration) by the
action of which the machine is raised directly from the
ground into the air. This does away with the necessity
for getting the machine under a gliding headway before
it floats, as is the case with the aeroplane, and consequently
the helicopter can be handled in a much smaller
space than is required for an aeroplane. This, in many
instances, is an important advantage, but it is the only
one the helicopter possesses, and is more than overcome
by its drawbacks. The most serious of these is that the
helicopter is deficient in sustaining capacity, and requires
too much motive power.

Form of the Ornithopter.

The ornithopter has hinged planes which work like
the wings of a bird. At first thought this would seem
to be the correct principle, and most of the early experimenters
conducted their operations on this line. It
is now generally understood, however, that the bird in
soaring is in reality an aeroplane, its extended wings
serving to sustain, as well as propel, the body. At any
rate the ornithoper has not been successful in aviation,
and has been interesting mainly as an ingenious toy.
Attempts to construct it on a scale that would permit
of its use by man in actual aerial flights have been far
from encouraging.

Three Kinds of Aeroplanes.

There are three forms of aeroplanes, with all of which
more or less success has been attained. These are:

The monoplane, a one-surfaced plane, like that used
by Bleriot.

The biplane, a two-surfaced plane, now used by the
Wrights, Curtiss, Farman, and others.

The triplane, a three-surfaced plane This form is
but little used, its only prominent advocate at present
being Elle Lavimer, a Danish experimenter, who has not
thus far accomplished much....."
End quote.

Patricia

[Patricia J B]

I have researched many of the early orni patents, some of which have the defintion as part of their introduction, I will look them up and post the links here.

Patricia


A couple of early orni patents which describe the term 'ornithopter'.

[Tweener]

Interesting reading. :D ;) Here's little about the design idea. I have no doubt whatsoever that Nathan will consider it an ornithopter, but I was taking the high road by suggesting the oscillopter designation. Front canard with rear flappers and a different flapping arrangement to isolate the oscillation effect from the fuselage. After I saw Patricia's in-cockpit test run video of the Toronto ornithopter, I realized that something should be done about that violent bouncing since the few aircraft I've taken the controls of ([Cessna 172/182 and Aeronca Champ] while flying with certified pilot instructors) have had very touchy control input. Good for precise control, but bad for trying to control while you're being slammed up and down.

[Patricia J B]

Here's one more exerpt from an early patent showing the common usage of the word ornithopter: Then I'll get back to discussing current orni's !
[The typo's were in the original patent as presented in the online 'espacenet' European patent website]

QUOTE:
EUROPEAN PATENT OFFICE

Description of GB146648


PATENT SPECIFICATION

iA Application Date: Apr, 15, 1919,No. 9629/19. L, Complete Left: Oct. 8, 1919.

Complete Accepted: July 15, 1920, PRlOYISIONAL SPECIFICATION.

Improvements in or relating to Ornithopter Flying Machines.

I, HENRY SEC'ET.xr Dixox, of 11, Woodgrange Atvenue, Ealing Common, in the County of MIiddlesex, Engineer, do hereby declare the nature of this invention to be as follows: This invention relates to flying' machines of the ornithopter type in which hinged wings are moved up and down around their hinges so as to exert. the necessary lifting power. The improvemients are especially designed for a machine of this type adapted to be worked by man power.

According to this invention the two wings, which are hinged together at the centre so as to be free to move up and down around the central hinge, are contnected itogether by resilient means which resist the tendency to fold the wings in the upward direction and tend to, bring the wings normally into approximately the horizontal position or slightly tilted
END QUOTE

Cheers,
Patricia

[Patricia J B]

Interesting reading. :D ;) Here's little about the design idea. I have no doubt whatsoever that Nathan will consider it an ornithopter, but I was taking the high road by suggesting the oscillopter designation. Front canard with rear flappers and a different flapping arrangement to isolate the oscillation effect from the fuselage. After I saw Patricia's in-cockpit test run video of the Toronto ornithopter, I realized that something should be done about that violent bouncing since the few aircraft I've taken the controls of ([Cessna 172/182 and Aeronca Champ] while flying with certified pilot instructors) have had very touchy control input. Good for precise control, but bad for trying to control while you're being slammed up and down.

Yes, you've zeroed in on one of the major problems of manned orni's ! Pitching and heaving of the fuselage does make it very difficult to control. I've always said that it's perfectly possible to build a manned orni that is capable of sustained flight but that can't be flown because the pilot can't control it while being tossed around like a cork on the ocean.

We have to work on ways to minimize either pitch and heave itself or ways to prevent that pitch and heave from reaching the pilot.

Cheers,
Patricia

[chadtgreen]

CNN posted a relevant article on this today.

Flying like a bird at 5,000ft, the winged wonder
http://www.dailymail.co.uk/pages/live/articles/technology/technology.html?in_article_id=425452&in_page_id=1965

Yves Rossy's website is www.jet-man.com.

[Tweener]

CNN posted a relevant article on this today.

Flying like a bird at 5,000ft, the winged wonder
http://www.dailymail.co.uk/pages/live/articles/technology/technology.html?in_article_id=425452&in_page_id=1965

Yves Rossy's website is www.jet-man.com.It's interesting, but definitely not anywhere near an ornithopter and really has no relevance to this forum or thread. The only way that can be likened to "flying like a bird" is the freedom from a fuselage. I don't think I've ever seen a bird with miniature jet turbines strapped to it's wings.

[NChronister]

The definition from the 1912 Jackman an Russell book, "The ornithopter has hinged planes which work like the wings of a bird." does not seem to exclude a contribution from fixed wings. The phrase "like the wings of a bird" is totally open to interpretation.

Patricia, could you point out where there is a general ornithopter definition in those patents? I did see something about the wings producing both lift and thrust, but it seemed to be saying that was the goal of the "present invention" rather than a characteristic of all ornithopters.

Does anyone know of the term "ornithopter" having been used prior to 1912?

[NChronister]

This guy HENRY SEC'ET seems to think that his ornithopter will produce lift directly by pushing the wings down against the air. Some ornithopters use a one-way valve or other mechanism so that the wing can push directly down against the air, and then rise unimpeded to begin another cycle. Remember the car with the pulsating umbrella on top?

Most ornithopters rely on forward motion to provide most of the lift. In this case the machine must still "push down" in order to overcome the torque exerted on the wing by the lifting force. But how much of the lift is actually due to flapping, as opposed to the aeroplane effect?

Recently I measured the static thrust of a Cybird. (Static means that the body is not moving, only the wings.) The Cybird weighs 7.2 ounces and it produces 5.2 ounces of static thrust -- or static lift if the Cybird is pointing straight up. Normally the Cybird flies with its body inclined at a slight angle, about 15 degrees. The amount of lift due to flapping equals the sine of the body angle times the static thrust exerted along the body axis. Therefore, the lift due to flapping is 1.35 ounces:

sin(15°)*5.2 ounces = 1.3 ounces

Being more generous, if we assume a body angle of 20 degrees then the lift due to flapping would be 1.8 ounces.

In conclusion, less than 1/4 of the Cybird's lift comes directly from flapping. The remaining portion must come from the aeroplane effect: flapping thrust accelerates the Cybird to some velocity where the forward motion of the model causes the wings to produce additional lift. The additional lift due to forward motion would be produced largely in the basal region of the wing where the vertical motion is minimal. It would also occur in the outer part of the wing by enhancement of downstroke lift and reduction of upstroke downforce due to modification of the local airflow relative to the wing.

Therefore I suggest it is a good idea to avoid confusing two concepts:

1. lift being produced by a flapping wing, and
2. lift being produced by the flapping of a wing.

They are not the same thing.

Further, since most of the lift of an ornithopter wing (at least in the Cybird example) is due to the aeroplane effect, I don't see why anyone should care whether the aeroplane surface is incorporated in the flapping structure or arranged separately.

[Patricia J B]

The definition from the 1912 Jackman an Russell book, "The ornithopter has hinged planes which work like the wings of a bird." does not seem to exclude a contribution from fixed wings. The phrase "like the wings of a bird" is totally open to interpretation.

Patricia, could you point out where there is a general ornithopter definition in those patents? I did see something about the wings producing both lift and thrust, but it seemed to be saying that was the goal of the "present invention" rather than a characteristic of all ornithopters.

Does anyone know of the term "ornithopter" having been used prior to 1912?

The Jackman and Russell book does exclude fixed wings from ornithopters in it's first paragrah quote "...VARIOUS FORMS OF FLYING MACHINES.

There are three distinct and radically different forms
of flying machines. These are:...." END QUOTE

and in the ornithopter definition paragrah QUOTE..."Form of the Ornithopter.

The ornithopter has hinged planes which work like
the wings of a bird. " END QUOTE

Their meaning is clear........ornithopter wings, unlike fixed wings are hinged [ie: pivoted] to allow them to flap like a bird........fixed wings are fixed firmly to the fuselage and cannot flap............I really can't see that this is "open to interpretation" at all. The whole point of that chapter was to define and separate the different forms of flying machines because this was at a time when fixed wings were coming to fore and ornithopters were fading out. The authors were taking the time to explain the differences so that they could then explain the advantages of fixed wing.

Re: the patents:
the patents show the meaning and common usage of the term "ornithopter" at the time. In both cases they state that their invention relates to aircraft of the "ornithopter" type and they then go on to describe the flapping of the wings. Neither of those patents includes fixed wings .

Re: Usage of the term 'ornithopter' before 1912.
This is something that I'm quite interested in. I've been looking but so far haven't had any luck.

Patricia

[Patricia J B]

This guy HENRY SEC'ET seems to think that his ornithopter will produce lift directly by pushing the wings down against the air. Some ornithopters use a one-way valve or other mechanism so that the wing can push directly down against the air, and then rise unimpeded to begin another cycle. Remember the car with the pulsating umbrella on top?

Most ornithopters rely on forward motion to provide most of the lift. In this case the machine must still "push down" in order to overcome the torque exerted on the wing by the lifting force. But how much of the lift is actually due to flapping, as opposed to the aeroplane effect?

Recently I measured the static thrust of a Cybird. (Static means that the body is not moving, only the wings.) The Cybird weighs 7.2 ounces and it produces 5.2 ounces of static thrust -- or static lift if the Cybird is pointing straight up. Normally the Cybird flies with its body inclined at a slight angle, about 15 degrees. The amount of lift due to flapping equals the sine of the body angle times the static thrust exerted along the body axis. Therefore, the lift due to flapping is 1.35 ounces:

sin(15°)*5.2 ounces = 1.3 ounces

Being more generous, if we assume a body angle of 20 degrees then the lift due to flapping would be 1.8 ounces.

In conclusion, less than 1/4 of the Cybird's lift comes directly from flapping. The remaining portion must come from the aeroplane effect: flapping thrust accelerates the Cybird to some velocity where the forward motion of the model causes the wings to produce additional lift. The additional lift due to forward motion would be produced largely in the basal region of the wing where the vertical motion is minimal. It would also occur in the outer part of the wing by enhancement of downstroke lift and reduction of upstroke downforce due to modification of the local airflow relative to the wing.

Therefore I suggest it is a good idea to avoid confusing two concepts:

1. lift being produced by a flapping wing, and
2. lift being produced by the flapping of a wing.

They are not the same thing.

Further, since most of the lift of an ornithopter wing (at least in the Cybird example) is due to the aeroplane effect, I don't see why anyone should care whether the aeroplane surface is incorporated in the flapping structure or arranged separately.


An aeronautical engineer recently did a similar but more detailed analysis of Schmid's aircraft using Schmid's own claimed numbers and found that the aircraft could not have flown as claimed.

Nathan, are you claiming incorrectly that the wake pattern and airflow around a flapping wing is the same as that around a fixed wing ??
During the last decade there has been increasing research into flapping wings and the more detailed the analysis becomes , the more we find that a fixed wing is not the same as a flapping wing [I have to laugh at what I've just said ! because this was obvious to the early pioneers.....if it's wings flapped, it was an ornithopter, if it didn't flap, it was a fixed wing aeroplane]....and if it had both fixed and flapping wings, it wasn't a pure aeroplane or ornithopter but something quite different entirely, a mixture of the two...a hybrid in fact. [ if the term 'hybrid is good enough for something as beautiful as a rose then it's good enough for something equally beautiful such as a fixed/flapping wing aircraft.]
Why can't you just accept that this was what the people who invented the word 'ornithopter' intended it to mean ?

[NChronister]

Patricia the referred to analysis of Schmid's ornithopters was completely invalid because as it turns out, the data points he used were from two completely different ornithopters. The first two data points are for the 1942 ornithopter and the third data point was the 1947 modified Grunau Baby IIa. The fact that there were two separate aircraft was not clear from my initial translation but should have been obvious: the photos clearly do not show a Grunau Baby and the weight didn't agree either.

I am making no claims about the airflow around the wing. I am only claiming that if you remove the forward motion, the lift is radically reduced.

In regard to the definition of "ornithopter" we still haven't pinned down exactly WHO first used this term or what they intended it to mean. At most you have shown that SOME people applied the term to aircraft with small fixed wing area -- just as I have shown that OTHER people applied it to aircraft with large fixed wing area. Given that the term has historically been applied to BOTH types of aircraft I think that in itself supports the broader definition.

Before you start with your HYBRID rhetoric, could you please tell me how you propose to draw the line separating "hybrid" from "true" ornithopters? You have been completely unwilling to address the key issue.

[Patricia J B]

Patricia the referred to analysis of Schmid's ornithopters was completely invalid because as it turns out, the data points he used were from two completely different ornithopters. The first two data points are for the 1942 ornithopter and the third data point was the 1947 modified Grunau Baby IIa. The fact that there were two separate aircraft was not clear from my initial translation but should have been obvious: the photos clearly do not show a Grunau Baby and the weight didn't agree either.

I am making no claims about the airflow around the wing. I am only claiming that if you remove the forward motion, the lift is radically reduced.

In regard to the definition of "ornithopter" we still haven't pinned down exactly WHO first used this term or what they intended it to mean. At most you have shown that SOME people applied the term to aircraft with small fixed wing area -- just as I have shown that OTHER people applied it to aircraft with large fixed wing area. Given that the term has historically been applied to BOTH types of aircraft I think that in itself supports the broader definition.

Before you start with your HYBRID rhetoric, could you please tell me how you propose to draw the line separating "hybrid" from "true" ornithopters? You have been completely unwilling to address the key issue.

Nathan,
I have not been unwilling to address anything. Please don't keep trying to turn this into a personal argument. It is a technical debate.

Re: the word 'hybrid'....what would you call something that is a mixture of two other things ? The scientific word is 'hybrid'....again, stop trying to make the word a personal insult, it's simply a scientific term that best describes a flapping/wixed wing aircraft and lets people know that it is not either completely flapping wing or completely fixed wing.

Re: your phrase... quote "HYBRID rhetoric" end quote
Again, stop trying to turn this into a personal argument.

Re: Who first used the term 'ornithopter'
I've proven that it was in use in 1912 and was probably [but unproven yet] in use before that because Octave Chanute who assisted with the previously mentioned book died in 1910. I'm quite interested in finding orni records dated before 1912 and will keep looking.

I've only listed a tiny number of the ornithopter patents that demonstrate the common meaning of the word ornithopter at the time they were filed. I thought that was all that was necessary but I'm perfectly willing to list dozens more if you want.

Re; Your quote:..." At most you have shown that SOME people applied the term to aircraft with small fixed wing area "...end quote

Most [not some] people applied the term to aircraft with no [not small] fixed wing area.


History does not agree with you, Nathan. The records that I've found so far prove this. These records show that very few people have stretched the original meaning in the past and that it is mainly you who is doing so now.

Are you trying to tell us that you think a flapping /fixed wing aircraft is exactly the same as a purely flapping wing aircraft ?

If you took the propeller off a Cessna 150 and replaced it with a small set of flappers , would you then call it an 'ornithopter' ?.....or would you call it a fixed wing Cessna 150 modified with flapper propulsion...a Cessna 150 hybrid.

Why does the word 'Hybrid get you so annoyed ?

Patricia.
Happy New Year Everyone :)

[NChronister]

I fail to see how that was personally insulting. Hybrid is rhetorical in the sense that is pre-assumes that which is under debate. An ornithopter inherently has some amount of fixed lifting surface. Therefore, an ornithopter with fixed lifting surface is not a hybrid. A hybrid would be, for example, an aircraft with a rotating propeller and flapping wings.

A hybrid car is one that is propelled by a gasoline engine and an electric motor. A car that has only a gasoline engine, but also has seats, is not a hybrid car.

Yes, a Cessna 150 with a flapping propeller would be considered an ornithopter. The simple fact that the sole source of propulsion is a flapping foil makes it an ornithopter.

I have tried to explain this dozens of different ways. Let me try one more. Consider the following illustration. This is a top view of an aircraft that is flying from right to left. Suppose the front wing (shown on the left) is a FLAPPING wing, and the rear wing (shown on the right) is a fixed stabilizer. Would you be willing to call this an ornithopter?

[Patricia J B]

I fail to see how that was personally insulting. Rhetoric refers to the persuasive use of language, and in this context I was trying to suggest that the word "hybrid" seems calculated to bias the discussion. I would prefer the word "hybrid" not be used because it pre-supposes that your ornithopter definition is correct. Since that is the vary matter we are debating, I don't feel it is appropriate to use the term "hybrid".



That is exactly what I meant when I said you were trying to turn this into a personal argument. My use of the word 'hybrid' is not 'calculated' to do anything to the discussion. I think of and discuss flapping flight from the viewpoint of scientific research and use the scientific term that best describes [scientifically] what I'm talking about. If we write up a scientific report of the flight of an aircraft that has both flapping and fixed wings and instead of mentioning that fact, we just refer to it as an ornithopter. the people who read that report [thinking that they are reading about a purely flapping wing experiment] are going to draw entirely incorrect conclusions about the performance of what they mistakenly believe is pure flapping flight. If they then are inspired to build one for themselves, the results could be disastrous.

Scientific research demands absolute truth in all descriptions and does not assign personal connotations to technical terms.

An ornithopter does not inherently have fixed lifting surfaces. Even if the wings are pivoted at the root, there is still rotation. The tail is movable too if it has a birdlike tail. The UTIAS orni had a one piece all-moving stabilator. If you want to get right down to minutiae, a bird's body is not fixed either but moves as the muscles move to flap the wings, twists and turns etc. But all this has nothing to do with the term 'ornithopter.'
The definition in the 1912 book shows the common usage of the word .
I think the authors would have been completely stunned at this discussion. The early pioneers were indulging in scientific research and invented terms that accurately described the invention and enabled it to be distinguished from other inventions. The fixed wing advocates quickly named their invention 'aeroplanes' [which was a more accurate description] to inform the world that this was something new [and better they thought] and was not to be confused with the flapping wing ornithopters.

The source of propulsion is not the determining factor as to whether an aircraft is an ornithopter or not. The determining factor is whether the source of propulsion is the same as the source of lift and that source is the flapping wings.
{birds don't have a huge set of fixed wings in addition to their flapping wings}

An aircraft that has both flapping and fixed wings does have 2 different things and most certainly is a hybrid. A flapping wing is not the same as a fixed wing in any way [recent research is only now discovering just how enormously different they are]. You can talk about irrelevant minutiae forever but you can't change that. Neither can you change the original meaning of the word ornithopter. It's there for all to see in the 1912 book and in hundreds of patents, papers, news articles etc for the past 100 years.

Neither History nor Science agrees with you .

[Patricia J B]

I have tried to explain this dozens of different ways. Let me try one more. Consider the following illustration. This is a top view of an aircraft that is flying from right to left. Suppose the front wing (shown on the left) is a FLAPPING wing, and the rear wing (shown on the right) is a fixed stabilizer. Would you be willing to call this an ornithopter?

This illustration didn't appear on my screen until just now [there was nothing after your words "Let me try one more" ]

I'm pondering my answer, will post tomorrow. I'd be interested in hearing what others think too. First though, could you clarify what you mean by the wing at the rear being a fixed stab. Do you mean that it is simply a fixed wing or do you mean that it is a fixed stab' with a movable elevator hinged to it and free to pivot or do you mean that it is a one-piece, all-moving stabilator [ in which case, it's not a fixed wing].
In any case, the stab/elevator is not usually referred to as a rear wing [even though it is, of course, an airfoil ] because it is not there nor is it large enough to provide the sustaining lift, it's function is to provide stability and control.

Re: Use of word 'ornithopter' before 1912.
I enjoy ferreting through old records so I'm interested in this as I said before.
So far, I've discovered quite a few references to 'Mechanical Birds' and 'Artificial Birds' but no references to ornithopters by the people at the time. All the same, we know from the fact that the 1912 book was published in 1912 and was being written before Octave Chanute died in 1910 that the word 'ornithopter' [which is used in the book] must have been in common use before 1910.

[NChronister]

The 1912 definition you posted did not claim that an ornithopter lacks fixed wing area.

Moreover, if a bird's body is not fixed, then neither is any "fixed" wing attached to an ornithopter. There will always be movement in any rigid or semi-rigid airfoil affixed to a body that has oscillating motion.

I'm not sure I see the importance of the "all moving" aspect of the stabilizer. Are you going to claim that any stabilizer on an ornithopter must be "all moving" in order for that aircraft to qualify as an ornithopter?

Either way, let's say the stabilizer is all moving and that it produces a stabilizing force that averages out to be some small percentage of the wing loading of the front/flapping wing. (For example if the front wing has a wing loading of 10 oz/ft^3 then the stabilizer might have a loading of 2 oz/ft^3. Taking into account the smaller size of the stabilizer, the actual stabilizer force would be much less than 1/5 of the total aircraft weight.)

I am assuming that the stabilizer must exert some amount of lift in order to perform its function as a stabilizer. Maybe that is not strictly true, particularly in the case of actively stabilized aircraft, but it certainly seems that real birds have a fairly high stabilizer loading, much higher than what I described above. So is this an ornithopter?

[NChronister]

This is from Aeromodeller Oct 1946.

[Patricia J B]

I'm not sure I see the importance of the "all moving" aspect of the stabilizer. Are you going to claim that any stabilizer on an ornithopter must be "all moving" in order for that aircraft to qualify as an ornithopter?


No I'm not going to claim that, please don't put words in my mouth.

[Patricia J B]

The 1912 definition you posted did not claim that an ornithopter lacks fixed wing area.



The 1912 definition described what an ornithopter is not what it isn't. If a definition has to define what a thing isn't then the definition would be ridiculously long. eg: An ornithopter is a flapping wing aircraft, it is not a fixed wing aircraft, rotary wing aircraft, balloon, dirigible, rocket, jet or a partridge in a pear tree.

[Patricia J B]

This is from Aeromodeller Oct 1946.

This is exactly what I'm objecting to. It seems to be mainly the modellers who are trying to stretch the meaning of ornithopter in order to allow more entries in their competitions.

You mentioned once before that a competition rule is not a definition and that's true but the trouble with that is that the stretched meaning advocates use it as a precedent to try to extend their incorrect meaning from modelling into all of orni history and specifically into manned orni history as you are doing right now with the above post.

[Patricia J B]

I'm not sure I see the importance of the "all moving" aspect of the stabilizer.

I am assuming that the stabilizer must exert some amount of lift in order to perform its function as a stabilizer. Maybe that is not strictly true, particularly in the case of actively stabilized aircraft, but it certainly seems that real birds have a fairly high stabilizer loading, much higher than what I described above. So is this an ornithopter?

I was just curious as to exactly what you meant because you were not using commonly used standard terminology when you referred to a the stab' as a 'rear wing'

Re: stab lift.....yes it would be producing a force called 'lift' but that lift would be acting in a downwards direction in the illustrated aircraft and would not contribute to sustaining the aircraft's weight under normal conditions of flight.

To answer your question:
If the aircraft is as illustrated ie: a flapping wing aircraft that has the same source for propulsion as for the lift to sustain the weight and that single source is the flapping wings and there are no fixed wings to augment sustaining lift [the stab is not a fixed wing and is not there to sustain weight] then yes, it is an ornithopter.......however.....
If you were to say that the wings are fixed and the tail is flapping then it would be obvious that the flapping tail is not capable of producing sustaining lift in addition to propulsion and that the fixed wings would be the lift producers, there would not be a single flapping wing source of both propulsion and lift and it would not be an ornithopter.

[Corbin_Dallas]

Alright, now I feel as though I should be quoting articles/books and getting heated and offended along with you, and the thing is, you guys could argue and reference forever and not get anywhere, and I'll tell you why:

You are BOTH right & Both a little wrong, depending on how/who's looking at it, but it's neither of your faults!! It's mainly due to referencing as you guys seem to like to do, but proves your knowledge isn't just you talking out your ASS(embly) ;) Thing is though, there still to date isn't an abundance of ornithopter information and official classification,definition,etc... Instead what I think the problem is with defining ornithopters (and what's mainly causing conflict between your guys' posts/refrencing ) is that more than likely, since it is hard even nowadays to define and get sufficient amounts of info said in stone, it would've been even more difficult then in the past for folks to do so
(not to mention that there's been some really funny reads for me while reading old science/library/school books, that have "facts" and definitions that have since been found to be wrong, incorrect or otherwise)
Therefore I don't doubt that just as cluelessly they sound while trying to explain on shows today (like the news, DM Discoveries this week, etc...) people writing about and coming up with little competitions for these bird-like flyings things they've seen or heard briefly about, would pass on a lot of incomplete/misleading/lot-left-to-imagination information about these things, which undoubtedly would get around and reach a lot more individuals then and scientific/rock solid info/research would have back then (and now) and in the event that a Scout leader in the sixties/seventies saw/heard about ornithopters in such a way & tinkered with balsa and tissue setups till he got a feasible Freeflying model that had flapping surfaces instead of propeller(s), he then could have very much so thought it to be a wonderful little project for the children in his troop, & we all know if in school/scouts/whatever, that if everyone is working on theirs and trying for their own little designs if allowed, that almost ANYTHING they show the adult the adult is going to say "Good job! That's neat, doin great! Hey everyone look at what _____ did with his ornithopter flyer!" And thus a kid who decided to add fixed wings to his poorly flying orni to see if it would help since he'd built regular balsa gliders before, it would totally be allowed, then everyone sees his and all those kids grow up thinking that an ornithopter is simply any flying craft with flapping wings (no matter the number of fixed wings or probably even propellers) and they would "know" because they "built them when they were little in their _(school,scouts...group)__" :rolleyes:

then they write books, tell people who are looking for info, etc.... and so on!
You see what I'm saying??

[B]JUST STOP ARGUING!! YOU ARE BOTH RIGHT/WRONG, BUT IT DOESN'T MATTER!!! JUST HAVE FUN KNOWING WHAT YOU KNOW, DON'T TRY AND CALL EACHOTHER OUT ON WRONG INFO, BECAUSE BOTH OF YOU GOT YOUR INFO FROM SOMEWHERE, SO IT'S NOT ANYBODY'S FAULT IF THEY WERE MISINFORMED, ESPECIALLY WHEN THE ONLY INFO OUT THERE IS SKETCHY TO BEGIN WITH!!!

-Not All Who Wander Are Lost-

-)v(^'I'I'-

[Patricia J B]

deleted

[NChronister]

Corbin, there is one reason why the definition "matters". It determines who can claim the title of "first ornithopter to fly successfully with a human pilot onboard", which Patricia and I both feel is an important aviation record.

Perhaps, as Corbin suggests, the solution cannot be found in history. Regardless of any historical basis, if a particular definition cannot categorize real aircraft in a meaningful way, then it is not a good definition. Patricia, since I think this is the key issue, I would like to discuss how your ornithopter definition performs in the classification task.

Without trying to reproduce your exact wording, I believe you said an ornithopter has flapping wings and no fixed wings. This leads to the question of whether the stabilizer qualifies as a fixed wing. I feel that a stabilizer IS a type of wing and that it can, at least sometimes, produce positive lift contributing to the support of the aircraft. In order to produce a workable definition, I feel you must do one of the following:

1. Not allow stabilizers, or
2. Not allow stabilizers that produce positive lift, or
3. Require that any stabilizer has a flapping action, or
4. Specify some other criteria for distinguishing between a stabilizer and a fixed wing.

Which one of these options would accurately reflect your idea of what should qualify as an ornithopter? (If you choose #4, please specify criteria.)

[ProfessorJoeVee]

This has been a facinating discussion, and I'm amazed that a few simple questions I asked prompted such a lengthy reply! Still, does anyone know the answers to the questions I posed back in post #8?

[Patricia J B]

Nathan, I'm very glad you edited out the personal comment that you made in your last post [I saw it though,in the email notification to me as did everyone else who is subscribed to this thread so I'm compelled to answer it]. I have not reacted angrily to anything at all, I'm surprised at you for saying something so completely false and for being unable to stick to technical issues. I'll say this just once more, please stop trying to turn this into a personal argument [you are the one who has made all the personal comments up to now] I have repeatedly asked you to stick to technical issues. If you do this again, I will stop discussing this with you, I'm not going to engage in a mudslinging contest.

To get back to a technical discussion. I agree with you that the definition is the key issue. I want to ponder the stabilizer issue so I'll post a reply later today.

[mlbco]

This has been a facinating discussion, and I'm amazed that a few simple questions I asked prompted such a lengthy reply! Still, does anyone know the answers to the questions I posed back in post #8?

ProfessorJoeVee,

I don't believe the FAI has a category for ornithopter world records. The AMA has a category for free flight indoor (rubber powered) ornithopters and I believe the record is on the order of 30 minutes duration. There is no such thing as a "distance flown" record that I'm aware of, just duration.

Most model ornithopters built today use either rubber power (free flight) or electric propulsion (free flight and RC). Designers will often build their own gearbox (easy to do on small models, tricky on bigger designs) and use a high performance brushless motor and Lithium Polymer batteries. If you can purchase an ornithopter kit like the Parkhawk, you can steal the mechanics from it and build your own design. I've successfully used the gearbox from a cordless screwdriver and a brushless 400 sized motor to power a 6 ft span RC ornithopter.

The only man-carrying ornithopter to fly in recent times used a gasoline engine and a custom reduction system. You can check that out at the U Toronto web site:
http://www.ornithopter.ca

Steve Morris

[Patricia J B]

ProfessorJoeVee,

I don't believe the FAI has a category for ornithopter world records.

Steve Morris

I was in touch with the FAI last year and they told me that they don't have an ornithopter category. They also don't certify 'World's Firsts' records. All they do is certify that a given flight took place at a given location, altitude, airspeed etc in a given aircraft. Application has to be made beforehand and the date, official observers etc arranged for....and the flight has to take place on the date arranged or the application becomes void. As to whether it's a 'First' or not is left up to the historians.

Re: Ornithopters.
They told me that I should go ahead with my flight when able :) using the official observers in my country of residence [ the observers that are affiliated with the FAI ] but that there would be no special orni category to file it in. If , in the future, more orni's take to the skies and there is an obvious need they would then go through the long and laborious paperwork required to process a new orni class. Since this would involve using volunteers, it won't be done unless there is a need for it. :(

Cheers,
Patricia

[Patricia J B]

This has been a facinating discussion, and I'm amazed that a few simple questions I asked prompted such a lengthy reply! Still, does anyone know the answers to the questions I posed back in post #8?

Re: orni power sources:

My models:

'Behemoth 4' ......KP00 electric motor.
........................Didel gearbox 20:1 ratio.
....................... Kokam 145 mah LiPoly battery.
........................wingspan: 14" weight: 15 grams

'Behemoth 3".......electric motor and Li Ion battery salvaged
....................... from a toy.
........................homemade gearbox, plastic gears, 19.2:1
........................Wingspan: 27 "
........................Weight: 55 grams

Nightingale N1 test model
..........:............Graupner Speed 700 BB Turbo Motor
......................Homemade multi-stage gearbox using delrin
......................gears with brass hubs from Boston Gear
......................2 packs of six 3000 mah Nicad batteries
.................................Wingspan: 8 feet
.................................Weight: 8 lbs

Nightingale Full-size 'manned' orni
..... MZ34 26 hp, 2 stroke, 1 cylinder engine.
..... homemade 3 stage speed reduction unit added to the
.... one-stage reduction unit that came with the engine.


Other peoples orni's
Spinmaster Toys uses an air motor in their 'Air Hog' orni and I've just seen a recent patent of theirs for a fluid motor in which both the strokes are power strokes.

Cheers,
Patricia

[macboffin]

DeLaurien ornothopter flew succesfully late last year after a two-year project.Pix and videos of the man-carrier and previous glow-motor powered r/c model are on the Net, just put DeLarien ornithopter in Google.

[macboffin]

Info and pictures of the manned ornithopter by Dr.James Delaurier, (Toronto University) at http//www.physorg.com/news73578550.htm
This was probably a World First success!

[Patricia J B]

DeLaurien ornothopter flew succesfully late last year after a two-year project.Pix and videos of the man-carrier and previous glow-motor powered r/c model are on the Net, just put DeLarien ornithopter in Google.

The Delaurier/UTIAS project has been on the go for 30 years not 2 years.
The model flew successfully in 1991. This led to the construction of the full-size manned orni which was completed in 1996. I was the first test pilot. We started testing in late summer 1996 and continued each summer. I did all the testing from the beginning up to and including the first lift-offs. I resigned at the end of 2001 and the new pilot took over.

Cheers,
Patricia

[macboffin]

No doubt that the bouncing up and down bad for the structure, let alone the pilot! Delaurien had a lot of problems with structural failures.
Ever noticed that birds also have their fuselages going up and down, but the "pilot", (the head) goes up and down in opposition, ie flies a straight line? Very noticeable on geese and swans. Any rate, how about paired wings a la Dragonflies ? Front pair up, rear pair down and vice versa.High speed pix show little "fuselage" motion vertically. Structural stresses shared over four wings instead of two, might be a better way to go?

[Tweener]

No doubt that the bouncing up and down bad for the structure, let alone the pilot! Delaurien had a lot of problems with structural failures.
Ever noticed that birds also have their fuselages going up and down, but the "pilot", (the head) goes up and down in opposition, ie flies a straight line? Very noticeable on geese and swans. Any rate, how about paired wings a la Dragonflies ? Front pair up, rear pair down and vice versa.High speed pix show little "fuselage" motion vertically. Structural stresses shared over four wings instead of two, might be a better way to go?Same concern here quite a few posts back. My idea has to do with the wings pivoting at a combined center of gravity and pressure. No oscillation would therefore be transferred to the fuselage.

[Kinkade]

Wow you guys can really split hairs. Forgive me for having a much more pedestrian explanation of what I think the definition sould be.

My own definition of an ornithopter comes to at least myself as being simply self evident. The sole defining element of an ornithopter is the method of lift and propulsion being the FLAPPING wing and at the same time,the absence of any other type of lift or propulsion other than the FLAPPING wing. So to ME at least, the primary mechanism that defines the term "ornithopter" is the wing... not the tail, not the body, not the undercarriage. It's really is that simple.

In one thread Nathan said something to the effect that "we shouldn't really care whether the aeroplane surface is incorporated in the flapping structure or arranged seperately". I totally disagree. The definition becomes null and void if we don't maintain the fundemental aspect of the definition itself! This would be like saying in the game of soccer that "we shouldn't really care if hands are used to transport the ball as well as feet". WRONG. Yes does matter if you want to call the game soccer.
If you want to stretch the definition of what is allowed then you may as well rename the game something else, like RUGBY. Soccer is not rugby and rugby is not soccer although they are similar games.

[Kinkade]

Another example of where one could split hairs but still be completely wrong would be aplying Nathan's same logic to helicopters. If you shouldn't have to care whether the aeroplane surface on an ornithopter is incorporated in the flapping structure or arranged seperately, then let's apply the same logic to helicopters and see what we come up with.....

If the lifting element doesn't have to be coupled to the propelling element then we could simply make a helicopter by separating the engine from the main rotor.....hmm. So we could let the main rotor freewheel and we could put the engine out front or in the rear with a seperate propeller to provide our thrust. The aerodynamic characteristics are maybe slightly different now but hey, we can still make our new "helicopter" take off vertically with a clever run-up of the main rotor and we can also hover ( although temporarily but so what) and we can descend vertically as well. It has a spinning rotor blade and it flies so it looks like a helicopter to me!

WRONG! By stretching the definition you LOSE the definition!
We have now created not a helicopter but an AUTOGYRO and an autogyro AIN'T a helicopter.

So Nathan, if you owned a fine restaurant would you allow Platypus to be served in place of roast duck? Hey, they both have "duck bills" right?

[NChronister]

Sean I think a more correct analogy would be to have a powered rotor, together with fixed wings. That would still be called a helicopter, wouldn't it?

When you talk about an unpowered rotor, the logical equivalent would be *unpowered* flapping wings. I guess like those flapping-wing kites?

The autogyro may be relevant though, because the lift is often divided between fixed wings and the unpowered rotor. I've talked to people about this, and I have been told that the fixed wing on the autogyro isn't controversial. It's something they would like to reduce, for aesthetic reasons, but it is a totally accepted way to improve the stability and handling characteristics of the autogyro. (They still call it an autogyro.)

This discussion has certainly taken on a different dimension from how it played out in the 1990s (when I was on the other side). Back then, NO ONE suggested that an ornithopter should get ALL of its lift from the flapping wings. We were merely debating HOW MUCH lift the flappers should be required to contribute. Now Sean and maybe Patricia are saying that ALL of the lift should come from the flappers. It's really quite unprecedented.

[NChronister]

Sean, since you recently joined the discussion, I want to post this again. This is Reg Parham's design from the 1930s, which had a lifting stabilizer and formed the basis for countless later designs including Lew Gitlow's Flapping Flyer. Are you going to go so far as to say even this is not an ornithopter?

http://www.ornithopter.org/parham.jpg

[Patricia J B]

.

My own definition of an ornithopter comes to at least myself as being simply self evident. The sole defining element of an ornithopter is the method of lift and propulsion being the FLAPPING wing and at the same time,the absence of any other type of lift or propulsion other than the FLAPPING wing. .

Yes !.....and this defining element is stated in the 1912 book [I mention the book only to show the way in which the term 'ornithopter' was used by the some of the most prominent people in aviation at that time ]

[Patricia J B]

This discussion has certainly taken on a different dimension from how it played out in the 1990s (when I was on the other side). Back then, NO ONE suggested that an ornithopter should get ALL of its lift from the flapping wings. We were merely debating HOW MUCH lift the flappers should be required to contribute. Now Sean and maybe Patricia are saying that ALL of the lift should come from the flappers. It's really quite unprecedented.

It's not unprecedented at all. This is stated in the 1912 book and is the meaning of 'ornithopter' that has been used for 100 years. The fact that an ornithopter has only one source for both the lift and propulsion and that one source is the flapping wings is the very spirit and essence of ornithopters.

If someone wants to add fixed wings, jet engines etc then think up a new name for the resulting aircraft as Sean suggests, don't expect us to change the long accepted meaning of the word 'ornithopter'

[NChronister]

First allow me to re-post the 1912 ornithopter definition:

"Form of the Ornithopter.
The ornithopter has hinged planes which work like
the wings of a bird. At first thought this would seem
to be the correct principle, and most of the early experimenters
conducted their operations on this line. It
is now generally understood, however, that the bird in
soaring is in reality an aeroplane, its extended wings
serving to sustain, as well as propel, the body. At any
rate the ornithoper has not been successful in aviation,
and has been interesting mainly as an ingenious toy.
Attempts to construct it on a scale that would permit
of its use by man in actual aerial flights have been far
from encouraging."

I don't see how you get from "hinged planes which work like
the wings of a bird" to having these hinged planes provide all the lift. The phrase "sustain, as well as propel" does appear later in the paragraph, where is it used in reference to soaring (not flapping) flight.

Many sources have defined the ornithopter as getting *most* of its lift from the flapping wings, or the flapping wings being the *main* source of lift, or even the flapping wings providing both lift and thrust, but I really don't know of any precedent for the flappers being the sole source of lift

But I don't want to go off on that historical tangent again. The ideas should be judged on their merits:

1. The "most" definition is flawed because "most" is too vague, too subject to interpretation. If you provide more specific criteria such as a percentage of total lift, then the definition becomes arbitrary.

2. The "all" definition makes no sense because real birds do not get "all" of their lift from the flapping wings.

[mlbco]

FWIW, here is the AMA defnition of a free flight model ornithopter:

17. Ornithopter. For event 210. An ornithopter
model derives its propulsion solely from the flapping
of its wing(s) or parts thereof. If part of a wing is
fixed, the projected area of the flapping part shall not
be less than that of the fixed part, and the fixed
part(s) must not extend ahead of the leading edge or
behind the trailing edge of the flapping parts. If the
model has more than one wing, these restrictions
apply independently to each wing, and the wings
shall be substantially identical in size, shape, relative
areas of fixed and flapping parts, and degree of flapping
motion. The projected area of a flapping part is
to be determined at a position midway between its
extreme positions. No part of the horizontal stabilizing
surface(s) shall be within a horizontal distance of
one-fourth the wingspan from any part of a wing, and
the total projected area of such surfaces shall not
exceed 50 percent of the total wing area. No protuberances
or extensions of the fixed or flapping parts,
which would satisfy the letter of these rules while
violating their spirit or intent are permitted. Takeoff
gear is not required. Twenty (20) seconds will define
an official flight.

[Patricia J B]

The first few paragraphs of George White's patent [in post # 12] state the 'sustain as well as propell' idea clearly.

I don't really want to keep going over the historical aspect either but it really can't be avoided because the term 'ornithopter' was first defined and used 100 or so years ago and it was invented to enable people to distinguish the different types of 'flying machine' being experimented with at the time.

Nowadays, there are many more types of flying machine in use and more are being invented every day. In most cases new names are being invented along with them.....names that more accurately describe their construction and flight characteristics.....there is absolutely no reason for flapping/fixed wing aircraft not to have their own name [a new name which could be divided into all the divisions based on fixed wing area , jet boost, new inventions etc ]... they would then start to develop their own World's Firsts records, competitions etc and scientific research and discoveries would be reported to the world accurately instead of misleadingly as is the case right now. Many people are interested in researching this type of aircraft for it's own sake for it's potential to develop high performing aircraft of the future. They don't call it an ornithopter because that does not describe it scientifically.

[Patricia J B]

FWIW, here is the AMA defnition of a free flight model ornithopter:

17. Ornithopter. For event 210. An ornithopter
model derives its propulsion solely from the flapping
of its wing(s) or parts thereof. If part of a wing is
fixed, the projected area of the flapping part shall not
be less than that of the fixed part, and the fixed
part(s) must not extend ahead of the leading edge or
behind the trailing edge of the flapping parts. If the
model has more than one wing, these restrictions
apply independently to each wing, and the wings
shall be substantially identical in size, shape, relative
areas of fixed and flapping parts, and degree of flapping
motion. The projected area of a flapping part is
to be determined at a position midway between its
extreme positions. No part of the horizontal stabilizing
surface(s) shall be within a horizontal distance of
one-fourth the wingspan from any part of a wing, and
the total projected area of such surfaces shall not
exceed 50 percent of the total wing area. No protuberances
or extensions of the fixed or flapping parts,
which would satisfy the letter of these rules while
violating their spirit or intent are permitted. Takeoff
gear is not required. Twenty (20) seconds will define
an official flight.

That certainly excludes the Schmid aircraft and the UTIAS aircraft in it's current configuration with the auxilliary jet engine.

[NChronister]

George White Patent

Patricia, we are in agreement that the history aspect is a waste of time. Historically there were people in both camps, so it doesn't help to resolve the matter. Having said that, George White's patent clearly indicates that he intended his ornithopter's flapping wings to produce both lift and thrust, but I don't see any indication that he would expect all ornithopters to do the same. I also don't see anything to indicate that the tail would not contribute some lift as well (if perhaps the minority). If I'm overlooking some key text in the patent, could you point this out to me?

AMA Rules

The AMA rule is a perfect example of how arbitrary a definition or contest rule can become when the goal is to regulate the amount of lift contributed by the fixed surfaces. This wording effectively banned models like Ken Johnson's Delta Belle shown earlier. Soon, however, Frank Kieser, Roy White, and others started building canard biplanes which placed most of the load on the forward stabilizer. Bob Mueser, who wrote the rules shown above, later submitted a rules change proposal in order to correct the loophole, but it was rejected by the AMA.

Coinage of New Terms

Patricia said "there is absolutely no reason for flapping/fixed wing aircraft not to have their own name". Let's take this idea and run with it for a second. Ignoring propeller assists, etc., I can conceive of three different categories for flying objects driven by flapping airfoils:

1. All thrust and all lift are provided by the flapping foils.

2. All thrust is provided by the flapping foils, and lift is provided by some combination of flapping foils and fixed wings.

3. All thrust is provided by the flapping foils, and all lift is provided by fixed wings.

As you know, I hesitate to further divide #2 into sub-categories, because I feel it is arbitrary to say, for example, everything over 65.3% is going to be called one thing, and everything under 65.5% is going to be called something else.

If I understand correctly, Patricia's proposal is that category #1 should be called "ornithopters", and we should come up with new names for categories 2 and 3.

Since ornithopters draw their inspiration from bird flight, I think an aircraft designed to be as much as possible like a real bird ought to be considered a true ornithopter. Birds are in Category 2! so shouldn't a Category 2 machine be considered an ornithopter?

I'm not saying that all ornithopters should be exactly like a real bird. If a machine is in Category 1, or if it has a lot of fixed wing area, or if it doesn't have feathers, it's OK to call that an ornithopter too, because these are all efforts in the same direction. We still have a long way to go. Today's ornithopters still don't have feathers, jointed wings, etc. like a real bird, but we have generously called them "ornithopters" because they were inspired by bird flight and approximate the flight of birds as much as we are able to at this point in time.

[Patricia J B]

George White Patent

Patricia, we are in agreement that the history aspect is a waste of time. Historically there were people in both camps, so it doesn't help to resolve the matter.

No, I don't want to nitpick but this is quite important. I don't agree with you that the history aspect is a waste of time. I didn't say it was a waste of time, I said that I don't really want to keep going over it with you. The historical aspect is relevant because the word 'ornithopter ' was first defined approx' 100 years ago and has been used to mean a certain thing ever since by most people. Now you want to stretch the meaning of the word . If we include all the aircraft that you want to be included then there is no point in having the word 'ornithopter' at all. The point of a definition is to describe something accurately so that there is no doubt in anyone's mind as to what it is first of all and secondly to enable it to be distinguished from something else.

In your reply to Corbin you said... quote:
" Corbin, there is one reason why the definition "matters". It determines who can claim the title of "first ornithopter to fly successfully with a human pilot onboard", which Patricia and I both feel is an important aviation record." ... end quote.

I agree with you that this is one reason why the definition matters but it isn't the only reason. Another equally important [perhaps even more important] reason is scientific accuracy. Both researchers and the general public are presently getting a confused idea of current progress in flapping flight research due to the inaccurate reporting of 'successful' flights of an ornithopter in the media and inaccurate claims on the internet. Many people that I know of now think that manned pure flapping flight has been achieved following the reporting of the July 8 flight of the UTIAS aircraft because it was referred to as an 'ornithopter' and most people past and present take that to mean pure flapping wing aircraft. This hinders the progress of flapping flight research, researchers have to know exactly what has already been discovered about flapping flight before they can venture forward into the unknown.

[NChronister]

Accuracy in the Media

Perhaps the UTIAS machine *is* an ornithopter, and in that case the reporting is accurate. :)

Really though, accurate communication depends on the pre-existing notions of the recipient. If UTIAS were to announce "successful ornithopter flight", that would mean different things to different people. Everyone in our field has a different idea of what may constitute an ornithopter. The general public has never heard of one.

That is why UTIAS press releases contain an embedded definition of the term. If people read the UTIAS definition then there should be no misunderstanding about what has taken place. Ironically, though, the ornithopter definition on the UTIAS web site isn't even met by their own machine. That certainly complicates matters.

It really annoys me when I see any kind of misleading information in print. But I'm not sure PUBLIC misinformation will impact the amount of progress that can be made by people in our field. Anyone who is really informed will look beyond the name and consider all different aspects of the design (such as whether it has a jet assist). There is one possible concern though: If the general public thinks the first successful manned ornithopter flight has already taken place, it could be a lot harder to get funding for new projects. (Personally I think the opposite would be true, but I can see why someone might have this concern.)

Another Historical Aside:

The McGraw Hill Encyclopedia of Science and Technology (not sure which edition I photocopied this from) has this to say about ornithopters:

Ornithopter. An aircraft whose wings beat like those of a bird, bat, or insect. Models are recorded as early as 400 BC (Archytas). Since the midnineteenth century some have been flown successfully; a number of machines of person-carrying size have been flown for short distances. The beating surfaces may be nonlifting (this is, propelling only), in which case they are properly called fins, or they may be wings which lift as well as propel."

This was written by none other than James FitzPatrick, not some uninformed journalist but rather a devoted researcher of flapping flight. FitzPatrick even constructed his own manned ornithopter, one that was pretty low on the fixed-wing lift scale. Despite the characteristics of his own design, he opted for a broader definition and chose to include nonlifting flappers.

[Kinkade]

Wow, more long winded debating.... :)

Seeing nothing more than a stalemate taking place here ( or perhaps "quagmire" would be a better term) let me again put forth nothing other than my own opinion about this after thinking about it.

I'm personally not really concerned about the term "ornithopter" loosely covering a broad catagory of flapping wing types of vehicles were it not for the fact that the aviation milestone we have all been waiting for really refers to a machine that flies solely by flapping wings.

As long as the aviation milestone and "world's first ornithopter" award goes only to a "pure" ornithopter then sure, the lexicon could get more lax as other hybrid vehicles are developed later. But again, MY personal issue with the term ornithopter is simply due to this recognition to be given to whoever achieves the true aviation milestone. Giving the recognition of "worlds first ornithopter" to someone who builds a fixed wing machine with flappers in the rear to propel it totally takes away from giving true credit to the one who achieves the aviation milestone. One could probably construct a flapping unit that takes the place of a typical prop drive and mount it to their back and have it propel a parasail, but that would definitely not be an ornithopter.

The aviation milestone that we've all been waiting for is a true ornithopter because the very thing that makes it a milestone is the level of difficulty to make a specific birdlike flapping wing aircraft work! Fixed lifting surfaces have been done. Hang gliders have been done. Props and jets have been done. Canards have been done.
Rotors have been done. Balloons, blimps and dirigibles have been done.
Pure flapping flight is what hasn't been done and that's what deserves the title of "world's first" so until that happens I think a strict traditional definition of the word ornithopter is required.

[Patricia J B]

Wow, more long winded debating.... :)

Seeing nothing more than a stalemate taking place here ( or perhaps "quagmire" would be a better term) let me again put forth nothing other than my own opinion about this after thinking about it.

I'm personally not really concerned about the term "ornithopter" loosely covering a broad catagory of flapping wing types of vehicles were it not for the fact that the aviation milestone we have all been waiting for really refers to a machine that flies solely by flapping wings.

As long as the aviation milestone and "world's first ornithopter" award goes only to a "pure" ornithopter then sure, the lexicon could get more lax as other hybrid vehicles are developed later. But again, MY personal issue with the term ornithopter is simply due to this recognition to be given to whoever achieves the true aviation milestone. Giving the recognition of "worlds first ornithopter" to someone who builds a fixed wing machine with flappers in the rear to propel it totally takes away from giving true credit to the one who achieves the aviation milestone. One could probably construct a flapping unit that takes the place of a typical prop drive and mount it to their back and have it propel a parasail, but that would definitely not be an ornithopter.

The aviation milestone that we've all been waiting for is a true ornithopter because the very thing that makes it a milestone is the level of difficulty to make a specific birdlike flapping wing aircraft work! Fixed lifting surfaces have been done. Hang gliders have been done. Props and jets have been done. Canards have been done.
Rotors have been done. Balloons, blimps and dirigibles have been done.
Pure flapping flight is what hasn't been done and that's what deserves the title of "world's first" so until that happens I think a strict traditional definition of the word ornithopter is required.

I strongly agree, this is exactly my opinion too .
Sean has got right to the crux of the matter in one post !

[Tweener]

Re: Canards. They make more sense than a rear stabilizer. I once saw a Beech/Raytheon Starship pilot quote that it makes no sense to push the tail down when you want to go up. It makes sense to pull the nose up instead. Since the primary function is pitch control and not level-flight lift, I still believe it should be allowed as a control option on any aircraft without changing the "type" of aircraft. After all, the Wright flyer was a canard design and that didn't stop them from calling it an airplane! BTW, watching geese fly, I have to believe that either their head shape contributes some lift, or they have a very tail-heavy design. ;)

[NChronister]

Tweener, that's exactly how I feel about the stabilizer. It makes no sense to push down when you could be pushing up, whether at the front or rear of the aircraft.

Sean's post really gives the illusion of getting right to the core of the matter, but it totally ignores one important fact: A machine does not either HAVE or NOT HAVE fixed wing lift. There is a whole *range* from 0 up to 100%. An ornithopter that operates like a real bird will be well inside that range, not at zero.

A real bird does not have a downforce stabilizer like one of Kinkade's models. A real bird has a rear fixed wing that contributes a significant amount of lift. We shouldn't even call it a stabilizer because the way it is loaded, it actually has a destabilizing effect, which must be compensated by the bird's active stabilization system. If a bird's tail acted as a stabilizer, it would bend upward on approach, to help flair the landing. Instead the tail deflects downward in order to increase the amount of lift force. At the same time, the wings sweep forward in order to maintain stability and further increase the total lift.

To say that the real milestone is to have a machine fly "entirely by flapping wings" also implies that you regard the fixed wing as some kind of driving force, which it is not. An airplane flies SOLELY by the force exerted by its propeller (unless it is getting lift from air currents). The wings are PASSIVE and do not contribute any power to make the airplane fly. An airplane cannot get off the ground with just wings and no propeller. In that sense at least, a tip-flapper like Schmid's DOES FLY solely by the flapping of its wings.

If you are going to insist that the milestone manned flapping-wing aircraft must derive all of its lift from the flapping wings and must therefore have a downforce stabilizer, then you have lost sight of the original goal, which was to fly like a bird. Schmid never lost sight of that goal. He drew his inspiration from bird flight and worked to move his ornithopters closer in the direction of a really bird-like arrangement. His 1942 ornithopter had flappers behind a main fixed wing, but his 1947 ornithopter had flapping outer wing panels, a much more lifelike configuration. (More birdlike anyway. Beetles have a front fixed wing with a flapping wing behind it.)

Sean somehow arrived at the other end of the scale and should be trying to load up the tail to make his designs more efficient and to make them steer more like a real bird. Instead he is saying that an ornithopter should not derive lift from its tail and in that way should not resemble a real bird.

Rather than continue to discuss where the lift comes from, I think perhaps we need to get back to basics. Whatever the design and mode of operation, an ornithopter is a machine inspired by the flight of birds. It doesn't need to have feathers and a beak, and it doesn't need to meet any other specific requirements, as long as it was motivated in some way by the ongoing effort to successively approximate bird flight.

[Patricia J B]

Rather than continue to discuss where the lift comes from, I think perhaps we need to get back to basics. Whatever the design and mode of operation, an ornithopter is a machine inspired by the flight of birds. It doesn't need to have feathers and a beak, and it doesn't need to meet any other specific requirements, as long as it was motivated in some way by the ongoing effort to successively approximate bird flight.

This statement completely misses the point. As Sean said, fixed wings, rotary wings etc have been done. The thing that hasn't been done by Man is pure flapping wing flight and it's the last thing yet to be done because of the high level of difficulty due to it's complexity. The person who achieves this will be the first person to do so .To call a flapping /fixed wing aircraft an ornithopter would deliberately mislead the public into thinking that the milestone had been achieved.


Trying to add lift or thrust devices other than the flapping wings misses the point altogether, does not achieve the milestone and goes against the very essence and spirit of the thing.

[Patricia J B]

Patricia the referred to analysis of Schmid's ornithopters was completely invalid because as it turns out, the data points he used were from two completely different ornithopters. The first two data points are for the 1942 ornithopter and the third data point was the 1947 modified Grunau Baby IIa. The fact that there were two separate aircraft was not clear from my initial translation but should have been obvious: the photos clearly do not show a Grunau Baby and the weight didn't agree either.



Nathan,
Where is the proof of the 2nd aircraft ? This is the only aircraft that you have shown us a photo of and it certainly looks like a modified Grunau Baby to me [the nose section is practically identical etc]. The photo that I've posted below is a Grunau Baby 11b not the 11a but still, you can see the similarity with Schmid's aircraft. EDIT: [the 11b had a longer nose and wider cockpit than the 11a ]

1st photo...Schmid's aircraft.
2nd photo Grunau Baby sailplane.
3rd photo.....another photo of Schmid's aircraft

If Schmid did experiment with an aircraft with flapping wing tips instead of the tail flapper, it sounds very much as if he was gradually eliminating the fixed wing in order to gather more accurate flapping flight data. The airflow from the fixed wing in the photo would have swamped the airflow from the flappers and any measurements would have been an inseperable mixture of the two. I think that Schmid thought of his aircraft as a flying laboratory to test flapping wings not as 'The first manned ornithopter' as you insist on calling it. Had the war not intervened, he would very likely have quickly improved on his design but his experiments were stopped before they were finished. There don't seem to be any records of his continuing after 1947 and there don't seem to be any of his notes etc in existence at all which I find odd for a scientist or engineer. Most designers are continually doodling sketches and writing notes on anything available....hence the famous 'back of an envelope'

I have found a few German patents issued during the war that relate to flapping wings [I think !....if the Google translation into English is accurate] so why was Schmid's design not continued ? ]

All this is interesting but it is not relevant to our present discussion.

Sean really has said it all.
The last aviation milestone is manned pure flapping flight. Historical records prove that most people define ornithopter as a flapping wing aircraft with no fixed wings. There have always been one or two people like Nathan who want to include fixed wings in the definition of ornithopter but the last aviation milestone isn't flight with both fixed and flapping wings, it is flight with flapping wings only. This is a technical fact that can't be changed. Historically, this milestone has always been referred to by most of the world as the flight of an ornithopter. This is both a technical description and the spirit of the thing. Anyone claiming the first manned orni flight will have to describe their aircraft and if it turns out to have fixed wings, they will not only look like a fraud , they will be a fraud.

[David Hipperson]

This is an interesting discussion and the concept of a flapping wing ornithopter to me is fascinating but I wonder at it's practical application even with the most modern of materials. It became obvious during the days of the Kremer prize for man-powered flight that even an efficient glider with a manpowered propeller could only make the most limited of hops until Paul MacCready came along plus the access to even more modern (at the time) materials. The fact that a first rate cyclist could achieve human powered flight proved the possibility but not the practicality. By their very nature the old concept of a man powered ornithopter (i.e run along flapping some sort of wings does not look as if it will work) but some variation on the theme might. Essentially a flapping wing "hang glider" where initial flight comes from slope lift and then additional 'power' is added by the pilot may well do it. However, the idea of a man providing sufficient power to lift his own weight and that of his flying machine is beyond me.
I'll applaud any one who can do it but the the 1+ : 1 power ratio seems to be asking more than the physical capability than anyone I'm aware of.

[Tweener]

This is an interesting discussion and the concept of a flapping wing ornithopter to me is fascinating but I wonder at it's practical application even with the most modern of materials. It became obvious during the days of the Kremer prize for man-powered flight that even an efficient glider with a manpowered propeller could only make the most limited of hops until Paul MacCready came along plus the access to even more modern (at the time) materials. The fact that a first rate cyclist could achieve human powered flight proved the possibility but not the practicality. By their very nature the old concept of a man powered ornithopter (i.e run along flapping some sort of wings does not look as if it will work) but some variation on the theme might. Essentially a flapping wing "hang glider" where initial flight comes from slope lift and then additional 'power' is added by the pilot may well do it. However, the idea of a man providing sufficient power to lift his own weight and that of his flying machine is beyond me.
I'll applaud any one who can do it but the the 1+ : 1 power ratio seems to be asking more than the physical capability than anyone I'm aware of.I believe you've missed the point. No one here expects this to be man (muscle)-powered, but powered by some type of engine. The Big Question that is being debated is whether the flappers only behave as the lifting surface as well as the thrust producing mechanism, or whether other fixed lift producing surfaces may be employed with flappers providing the thrust, and/or how much lift may these surfaces contribute before it is no longer called an ornithopter, but rather a hybrid type aircraft. At this juncture it seems that the only real point of agreement is that using any other method of propulsion as an assist is cheating.

[NChronister]

Historical records prove that most people define ornithopter as a flapping wing aircraft with no fixed wings.
Patricia, that claim was not substantiated by your earlier posts. Moreover, historical records could only show how the term was defined in the past and by certain individuals. Historical sources have no bearing on how most people define it today. You would need to do a poll, and even if you could do such a poll in a scientifically valid way (with random sampling, etc.) it wouldn't have any bearing on how the term *should* be defined, due to the errors of logic that I have repeatedly described.

...the last aviation milestone isn't flight with both fixed and flapping wings, it is flight with flapping wings only.
I can't see why eliminating the fixed-wing lift would be regarded as a "milestone", since it can be achieved through progressive reduction.

Why do you call it "the last" aviation milestone? Wouldn't an even more challenging and more final accomplishment be to use feathered, variable-area wings like a real bird? Then the machine would really deserve to be called an "ornithopter" because of its "bird wings".

Why do you place so much emphasis on the lift share, yet not seem to care whether the "ornithopter" has any other bird-like features like feathers or a variable-area wing?

Adalbert Schmid

Thank you for posting the Schmid and Grunau Baby photos. You can see even here that the cockpit and tail are quite different. Schmid's 1942 ornithopter weighed only 60 kg, whereas a Grunau Baby weighs about 150 kg.

You expressed surprise at the lack of additional Schmid documents. It takes time to locate that sort of information. To say it doesn't exist is a premature conclusion. I first learned of Percival Spencer through a brief, unreferenced description in a book, and it took several years to acquire the documentation that I have now. That was without the difficulties posed by the war, occupation, different country, different language, lack of census records, etc.

Schmid specifically referred to his 1942 machine as the first successful flapping-wing aircraft. Even if you regard the "fully flapping" idea as a greater challenge, or hold it in higher regard due to the fact that it hasn't happened yet, you have to admit that what Schmid did was a very difficult and impressive achievement. That is a simple fact that stands aside from names.

[NChronister]

Here are some more articles about Schmid. As you can see, Schmid was very old, and this likely explains why his work did not continue. (Also there was a ban on sport aviation after the war.) The 1947 aircraft is described in Lange's Typenhandbuch des deutschen Luftfahrttechnik, and in Schmid's letter to Weltluftfahrt. Lange provided the year, which was not given in Weltluftfahrt.

[Patricia J B]

you have to admit that what Schmid did was a very difficult and impressive achievement. That is a simple fact that stands aside from names.

Yes, of course I do, it was an outstanding achievement. I've always said that.

Out of interest, here's another photo of a Grunau Baby [probably a 11b]. You can see the similarities to the Schmid aircraft above. Naturally he would have changed the tail to make room for the flappers [he would have had to move the horizontal stab' aft] and the vertical stab/rudder has been slightly clipped in Schmid's aircraft . The nose sections of both aircraft are the same. In Schmid's aircraft the raised cockpit and wing mount of a Grunau Baby has been shaved off down to the top longeron and the fixed wing re-attached there. Schmid used a Grunau Baby 11a [2a]. I haven't been able to find a photo of a 11a yet. The 11b was far more popular.

Here's some info from the Smithsonian Air And Space Museum.....quote..." ..Schneider continued to refine the airplane and introduced the Baby II A and the definitive II B. The II A introduced a wing of slightly greater span to accommodate spoilers for glidepath control, ailerons with a narrower chord, and for the first time, a canopy and windscreen for the cockpit. When the Baby first appeared, it was accepted wisdom that the pilot should feel as much unimpeded airflow as possible, the better to sense rising and falling currents of air, temperature changes and the like. On the II B, Schneider changed the spoilers to the more powerful Schempp-Hirth, 'parallelogram' configuration and added a wheeled launch dolly that the pilot jettisoned immediately after takeoff. Other versions followed but more Grunau Baby II B gliders were built than all other variants combined. .." end quote:

[Patricia J B]

Here's a doodle showing how A Grunau Baby might have formed the base for Schmid's aircraft.

[Patricia J B]

I can't see why eliminating the fixed-wing lift would be regarded as a "milestone", since it can be achieved through progressive reduction.



If it was that easy, it would have been done years ago. A 'Milestone' is something that hasn't been done yet due to the difficulty of doing it and marks a great leap forward in knowledge and/or technology !

[Patricia J B]

Why do you call it "the last" aviation milestone? Wouldn't an even more challenging and more final accomplishment be to use feathered, variable-area wings like a real bird? Then the machine would really deserve to be called an "ornithopter" because of its "bird wings".



Yes, you're right it's not the 'last' milestone. I thought that as I was posting that message but I didn't bother editing it because I had to take my puppy [who is not yet housetrained] out. Sometimes life pushes technical debate aside ! :)

Using variable area wings with feather-like advantages would [and will] be a great accomplishment but not as great as flapping wings. Flapping wing flight is a different category of flight just as rotary wing is a different category altogether from fixed wing flight. Variable area and feathers are a refinement which might lead to greater performance of any of those wings, they're not a different category of flight.This is why pure flapping flight is regarded as a milestone...it represents a new type of flight . Fixed wings were the milestone in 1903 and that milestone was achieved by the Wrights and others. That was a great leap forward in knowledge at that time. Manned, pure flapping wing flight will mark a huge leap in knowledge and achievement in spite of those who would detract from it.

[Patricia J B]

Schmid specifically referred to his 1942 machine as the first successful flapping-wing aircraft.

Did he call it an ornithopter ?

[Patricia J B]

Patricia, that claim was not substantiated by your earlier posts. Moreover, historical records could only show how the term was defined in the past and by certain individuals. Historical sources have no bearing on how most people define it today. You would need to do a poll, and even if you could do such a poll in a scientifically valid way (with random sampling, etc.) it wouldn't have any bearing on how the term *should* be defined, due to the errors of logic that I have repeatedly described.

You expressed surprise at the lack of additional Schmid documents. It takes time to locate that sort of information. To say it doesn't exist is a premature conclusion. .

Nathan, I have proved it. The records show that the majority of the world used and continues to use the word 'ornithopter' to mean flapping wings only.

The records date from over 100 years ago and continue right up to and including the present time.

There have always been one or two people, like you, who tried to give the word their own definition for various reasons but they have not succeeded and will not succeed in the future.

Re: your comment:
"Historical sources have no bearing on how most people define it today........it wouldn't have any bearing on how the term *should* be defined, due to the errors of logic that I have repeatedly described" ... end quote

I can't believe you said that !
Man has used the word ornithopter in a scientifically accurate way for over 100 years. The definition is crystal clear and has been proven to be well-suited for both technical and general use right up to and including the present day.


Re: Your comment:
"...You expressed surprise at the lack of additional Schmid documents. It takes time to locate that sort of information. To say it doesn't exist is a premature conclusion."...end quote

I didn't say they don't exist !!!, I said " there don't seem to be any notes....."
[which means there may well be notes but we haven't found them yet !!!!]

[Patricia J B]

Nathan, we've discussed technical and historical matters in great detail but there's one thing that we haven't mentioned at all and that is 'The Spirit Of The Thing !'

You seem to be missing the point of it all, in other words, you're missing the spirit of the thing.

Man has always wanted to pursue the unknown and do the thing that hasn't been done. [ that's what milestones are all about]....manned pure flapping flight has not been done . There is enormous excitement brewing as to who will be the first. We have chosen to continue to call our all-flapping wing aircraft 'ornithopters' as has been done for 100 years for many reasons, one of which is to honour those early pioneers.

To try to have fixed wings included in all this is mystifying. As I said before, fixed wings have been done. All-Flapping wings have not been done, pure flapping wing flight is the goal which is causing so much excitement, that's the spirit of the thing. To try to say that an all-flapping wing aircraft actually has fixed surfaces embedded in the body etc etc is completely missing the point.

[Patricia J B]

Quote from Adalbert Schmid:

".......Even today when the flapping wing and fixed wing are divided, the future of development is pure flapping wing flight. I know this path, and I am ready to show the way. There will be no shortage of success. The flapping wings will revolutionize sport aviation.

Yours, Adalbert Schmid "

[NChronister]

Flapping wing flight is a different category of flight just as rotary wing is a different category altogether from fixed wing flight.

I think what I've been getting at is: Yes, flapping wing flight is a distinct category from rotary-wing, but an aircraft like Schmid's or DeLaurier's is in the *same* category as your Nightengale project because you can get from one to the other by *gradually* changing the size or lift share of the fixed surfaces.

http://www.ornithopter.org/scale.gif
Your quote from Schmid shows that you and he were of like mind on this: it's better to reduce the area of the fixed wings when that becomes practicable.

Schmid never used the word "ornithopter" because it was not part of the German language in his time. Does "ornithopter" mean something different from "flapping-wing aircraft"?

You seem to be missing the point of it all, in other words, you're missing the spirit of the thing.

The spirit of the thing is to make something that flies like a bird. Bird's have a lifting body and tail.

Don't build an ornithopter because you want to be the *first*. Build it because you want to build an ornithopter. It doesn't have to be made into some kind of competition.

[Patricia J B]

message deleted

[Patricia J B]

Don't build an ornithopter because you want to be the *first*. Build it because you want to build an ornithopter. It doesn't have to be made into some kind of competition.

Nathan,
Again please stop trying to make this personal by attributing completely false motives to me.
I am building Nightingale because I want to build an ornithopter. As you know , I'm fascinated with flapping flight and would build an orni even if the world already had a thousand other orni's. I'm hoping that Nightingale will test many ideas and contribute to manned flapping flight research.

The 'competition' as you call it hasn't been made by anyone. It is simply the scientific and historical fact that manned pure, flapping wing flight has not yet been achieved and that is what the human race is trying to achieve right now. That is the spirit of the thing and to achieve what has not yet been achieved is the spirit of the human race.

[ProfessorJoeVee]

Back on topic, what do people here in the forum know about research that has gone into the commercial viability of man-powered ornithopter flight? It seems that such a vehicle would have great potential to compete with fossil fuel-powered aircraft.

[Patricia J B]

Back on topic, what do people here in the forum know about research that has gone into the commercial viability of man-powered ornithopter flight? It seems that such a vehicle would have great potential to compete with fossil fuel-powered aircraft.

I don't think there has been much research into the commercial viability. Everyone's concentrating on getting an orni to sustain flight first. Once that is successfully accomplished then, no doubt, the commercial uses will be apparent.
Re: competing with fossil fuel powered engines.
An engine powered orni that uses alternate fuels could successefully compete with fossil fuel powered orni's. It doesn't have to be man-powered to compete.
Due to the difficulty of designing a man-powered orni, I think that sustained flight in an engine powered orni will be achieved first, then alternate fuels will be used and finally someone will succeed in man-powered orni flight but I think that the future commercial users of man-powered orni's will be small, special interest groups eg: Military, Sport Aviation whereas engine-powered [with alternate fuels] orni's will have wide commercial uses.

Cheers,
Patricia

[Kinkade]

I'm sorry Nathan, as much as I have respectfully referred to you as the "gatekeeper" of ornithoptology for so many years, now I think the old Harley Davidson axiom applies to you.....

"If you have to ask, you wouldn't understand".

Or, remember how Crocodile Dundee said:
"That's not a knife......now THAT'S.... a KNIFE!".

Well, I have prediction that when it happens, people around the world will say now THAT'S AN ORNITHOPTER! referring to the REAL THING without fixed surfaces regardless of who or what defines bureaucratically the term ornithopter.

I also predict even with all of my business related issues that I will be the first to do it. I've designed a new machine around Patricia ( i.e. a 92 pound pilot) and you'd be surprised at how small the machine can actually be. It does not have to be as big as the UTIAS machine and smaller equates to less expensive to build too. The machine will be similar in size to a Benson Gyrocopter. 92 pounds is NOT a lot of weight! I'll probably put RC in the full scale machine and fly it by radio first with 92 pounds of dead weight in it, then let Patricia take the controls.

If I get the CNC machines that I'm hoping to get, it will only be a matter of time before I built it. Everyone will see my flying RC prototypes first though and once you see those it will be obvious that the full size design will be a shoe-in. I plan on builiding it in my garage the way a person builds a kit plane, one step at a time as made possible by finances.

[Tres Wright]

Would Patricia have to hold a TX while flying it? ;) I've often thought that it would probably be easier for me to fly a full size plane if they made one that had TX-styled controls :D

[Tweener]

Back on topic, what do people here in the forum know about research that has gone into the commercial viability of man-powered ornithopter flight? It seems that such a vehicle would have great potential to compete with fossil fuel-powered aircraft.Oh, you were originally talking about muscle power! :o I thought you just meant manned. In answer to that question, I don't think anyone in their right (Wright?) mind would even consider it until a working manned engine-powered ornithopter is successfully built and perfected. In a relative way to our fine feathered friends, we're just to weak and heavy. Also, it's their bodies that allow them to fly whereas we have to add even more weight to ourselves in the form of a machine to achieve the same aerodynamic configuration.

[NChronister]

Patricia, I'm sure anyone reading this forum will recognize that that was not intended as a personal attack. I was not faulting you for trying to promote your own project. I was only making a suggestion about how to promote it more effectively, which you can take or leave. Sorry if I failed to distinguish between wanting to be 1st and wanting to do something that has never been done before.

Well, I have prediction that when it happens, people around the world will say now THAT'S AN ORNITHOPTER!

My concern is that just such a thing will happen, not because the new ornithopter is better, or more of a real "ornithopter", but just because people don't know anything about the previous ones. That just wouldn't be fair!

There are some gray areas even between airplanes and helicopters (such as airplanes that can hover). But almost always, it is pretty easy to tell the difference between an airplane and a helicopter. The airplane has a rotating propeller that provides horizontal thrust, whereas the helicopter has a rotor that provides vertical lift. The same dichotomy does not apply to ornithopters. Even if there are no fixed surfaces, the flapping wings are almost always aligned horizontally and produce a horizontal thrust like an airplane propeller.

Real world aircraft have clustered around the horizontal thrust airplane approach and the vertical lift helicopter approach. With flapping wings, there is no clustering at extreme ends of the lift share scale.

...except for the recent abundance of commercial designs with downforce stabilizers. Ironically that is the result of trying to make ornithopters look more like birds. A bird-shaped ornithopter without a bird's active stabilization system needs to have a very forward center of gravity in order to be stable, and therefore it needs the downforce stabilizer that birds don't have.

I've got some more info that I will post separately just to break things up.

[NChronister]

In the past, I haven't given much credence to dictionary definitions because of my assumption that they are written by people outside our field. They might, however, give some indication of what people *outside* our field think about ornithopters. Accordingly, I collected eight different definitions from various dictionaries plus Britannica and World Book encyclopedias.

These are all the ones I could find, not selected in any way. I went to the library and the bookstore, so different editions of the same dictionary could be included. But where I had exact duplicates (#3) I only typed it once.

1. a flying machine using flapping wings to imitate the flight of birds.
2. a machine designed to fly by flapping its wings like a bird.
3. a machine designed to achieve flight by means of flapping wings.
4. a machine shaped like an aircraft that is held aloft and propelled by wing movements.
5. a flying machine that operates using flapping wings. Although the earliest aircraft designs imitated the flapping wings of birds and many prototypes have been flown in the past 100 years, no ornithopter has ever been commercially successful.
6. an aircraft designed to derive its chief support and propulsion from flapping wings.
7. a heavier-than-air craft designed to be propelled through the air by flapping wings.
8. a hypothetical aircraft held aloft and propelled by wing movements.

Three of the definitions mention that ornithopters are intended to imitate the flight of birds. Six refer to flapping wings. Only half of the definitions say anything about lift share.

One definition says that the wings only need to propel.

Another says that the flappings wings must provide *most* of the thrust and lift. This definition would allow DeLaurier's machine to be called an ornithopter.

Two dictionaries (out of eight) used the phrase "held aloft and propelled by wing movements". I'm not sure if "held aloft by wing movements" is the same as "having all lift provided by the flapping wings" but I can see how one might interpret it that way.

And finally, an ornithopter must be "shaped like an aircraft"! :)

Some interesting tidbits:

1. Most of the dictionaries I checked don't even have "ornithopter".
2. Some dictionaries listed the word as obsolete or chiefly historical.
3. Word origin is listed as 1908 or early 20th century and from French ornithoptere in addition to the Greek roots.

At least based on these dictionary definitions, I don't see any concensus at all about the lift share issue.

[Patricia J B]

Patricia, I'm sure anyone reading this forum will recognize that that was not intended as a personal attack. I was not faulting you for trying to promote your own project. I was only making a suggestion about how to promote it more effectively, which you can take or leave. Sorry if I failed to distinguish between wanting to be 1st and wanting to do something that has never been done before.



Nathan,
You simply don't understand. I am not promoting my own project [perhaps you would point out just exactly where I was supposedly promoting my own project.] It was you who mentioned Nightingale not me. I haven't mentioned Nightingale at all. Nightingale has nothing to do with this debate. Once again, I will ask you to stop making personal remarks about me. { Attributing false motives to me IS a personal remark] This is supposed to be a technical debate.

In my experience it is always those who have no technically valid data who descend into personal comments and insinuations.

I will try once more to explain why I am building Nightingale. I have been fascinated with all aspects of flight since I started flying at age 16. In addition to being a pilot, I have always been interested in aircraft design and engineering and the UNKNOWN. It's exciting and completely captivating in addition to being technically fascinating. I am not interested in re-inventing the wheel. So when I discovered orni's, I found my little niche.
Nightingale is being designed to conduct a wide variety of tests ie: explorations into the unknown. I hope to gather a large body of technical data on manned orni's.
I may or may not be first to sustain flight [ and of course I'd like to be first, who wouldn't ? ] but that is irrelevant. Nightingale's testing will go ahead regardless , simply because I'm CURIOUS ABOUT THE UNKNOWN.

This really is the clearest that I can put it Nathan. Anyway, as Sean said "If you have to ask, you wouldn't understand"

You obviously have some agenda of your own.

[Patricia J B]

My concern is that just such a thing will happen, not because the new ornithopter is better, or more of a real "ornithopter", but just because people don't know anything about the previous ones. That just wouldn't be fair!




When an ornithopter sustains flight for the first time, the hybrid fixed/flappers that helped to pave the way will certainly not be forgotten. They are an integral part of the story of manned flapping flight and anyone who claims the title of first must acknowledge them.

[NChronister]

I do have an agenda, which I have clearly stated. It is to ensure that people know about the history of flapping-wing flight so that someone cannot come along and unfairly claim to have been the first at something that was already done. (Obviously whether it was already done depends on the definition, but you know which one I subscribe to and why.)

Additionally, I would like to reverse the public misconceptions about ornithopters. Most people seem to think that flapping-wing flight that exists in nature cannot be duplicated by humanity. Further, a lot of folks seem to have a negative stereotype about anyone who tries to fly by flapping wings. They are perceived as crackpots, partly because of the perceived impossibility of flapping flight and partly because of the high degree of publicity received by past failures.

If we do not call Schmid's or DeLaurier's machine an "ornithopter" then we are acknowledging that no one has ever flown by flapping wings. If we acknowledge that no one has ever flown by flapping wings, then we are confirming the age-old notion that flapping flight is impossible (and that those who attempt it are crackpots). Personally I'd rather affirm that YES we can fly by flapping wings.

That was the essential message of Schmid's letter to Weltluftfahrt: I built this machine that proves we can fly by flapping wings. Now someone please continue to develop this work, take it farther, make it more like a real bird.

If someone increases the flapper lift share, they will have done something quantitatively new, and that is a great step forward in ornithopter research. But I do not believe that is a different category of aircraft worthy of a different name.

[Patricia J B]

Nathan, I think we've discussed this enough don't you ?

History and Science will always acknowledge that Schmid, Delaurier etc were part of the manned flapping flight story and paved the way but there's no getting around the scientific fact that their aircraft were not pure flapping wing aircraft. They themselves admit this and took pains to ensure that no-one thought they were claiming sustained flight of a pure flapping wing aircraft.

As you know, 'Science' has always acknowledged that each new generation of researchers 'stands on the shoulders' of the previous generation and takes what is already known about the subject and extends it into the unknown. Flapping flight research is no different. We are going the next step beyond Schmid and Delaurier.

So you need have no fear that previous experimenters will not be given the credit that they are due.

Flapping flight enthusiasts are no longer considered 'cranks or crackpots'. [ they haven't been considered crackpots for at least 10 years !!] ....UTIAS, DARPA,NASA, Discovery channel TV and the many universities that now have flapping flight programs have enlightened the world in that regard. That battle has been won, Nathan.

[NChronister]

That was a good point about Discovery channel, etc. and it does seem that a lot of progress has been made. I found everything you just wrote almost totally agreeable, and that is nice to see for a change. :) I also think it was a nice gesture to use the phrase "pure flapping wing aircraft" instead of the more contentious term "ornithopter".

There is some potential for confusion around the word "pure" though. I am imagining that the average person will assume "pure flapping wing flight" means "flight like a bird", when in reality you have gone one step further and eliminated the lifting body and tail. Therefore, to make it even more clear what you are talking about, a label such as "aircraft in which the entire supporting surface is flapping" (or in which the flapping surfaces provide all of the lift) would be more precise.

I think I understand now why you want your ornithopter not to have a lifting stabilizer. It poses a particular challenge that is greater than the challenge of an aircraft with fixed and flapping wings, and even though the amount of fixed lift is a continuously variable phenomenon, you have found a natural milepost by bringing it to zero. Zero is a special number, different from 23.7% or 13.5%. I don't think zero moves you into a new category of aircraft, but I can see how it's a natural marker that would make you feel good to achieve.

[Kinkade]

Nathan, I can somewhat see how the fixed wing/stab issues can muddy things with regards to the ornithopter definition, but jet assist has absolutely no excuse or justification. Jet assist aided Delauriers' machines airspeed and airspeed increased its lift to the point that it got off the ground. Delaurier claims the machine needs a bigger wing to fly without jet assist. Could this be the case? Absolutely. But why not just add a bigger engine for flapping since it's also clearly simply a matter of power? Why not flap the wings faster? Would the machine fall apart?

His last test proved the machine was airworthy with enough airspeed but it didn't generate enough airspeed from flapping wings so like I said..."no cigar" and certainly no champayne.

So I think you can dispense with any augmented power supply outside that of the flapping wings when it comes to a definition. That then leaves only your fixed surfaces debate.

Since the jet assist aided airspeed and airspeed aided lift then that's no different than gas bag attached to an early helicopter that couldn't get airborne without it. And if a helicopter can't get off the ground by it's own rotor power it's not really a helicopter is it?

There's another hair splitter for you....is an ornithopter an ornithopter if it doesn't fly? In this case the only difference would be the use of the words "successful" and "unsuccessful". Is an unsuccessful ornithopter still an ornithopter? Or do I really want to ask this question and start a whole 'nuther debate?? :eek:

[Kinkade]

That's fine with me. I'll be happy with the term "pure flapping wing aircraft".

I suppose the word ornithopter also applied to a man jumping off a bridge to his death with wings strapped to his arms! I guess I don't mind being removed from that association.

But you know...the time will come when we all really know what a REAL ornithopter is anyway. :D

[Kinkade]

By the way Nathan, your assertions about positive or negative tail force are actually moot due to experiments I did years ago with the SkyBird. Whether the tail deflects down like you say a real bird tail does, or it deflects upward like a Penaud ornithopter...it has little if any bearing on the engineering apects of the flapping wing. I thought I shared the anomolous aspects of that with you years ago...maybe you have forgotten.

With one of my SkyBirds...I think it was a custom smaller size "Robofalcon", back when I was working in Canada, I could fly the bird normally with the tail pitching up but I could also do the following: with a moderate power setting, push the stick forward to put the bird into a dive which would result in a temporary dive..keep holding the stick all the way forward as if to do an outside loop and lo and behold the bird would accelerate and then start to self stabilize, pull itself out of the dive as its airspeed inscreased, then maintain a horizontal trajectory and fly with the tail visibly pitching DOWN. In this mode the control inputs were reversed so it was very strange to fly but it did fly and it flew quite well. I never quite understood what was taking place aerodynamically during the abrupt tail pitch transition. I have not seen this in my park flyers, only the SkyBird but I bet if you moved the battery far enough to the rear you could pull the same thing off on a Slow Hawk.

But my point is, there was no significant difference in the machine whether it flew tail down, or tail up. Unless that is, if one is splitting hairs. :p

[NChronister]

Sure I'd be willing to say that if there is a second power source that it is not a pure ornithopter. I think the word "pure" makes the most sense in this context, and less sense in the context of whether or not there is a lifting stabilizer.

Sean, I know your birds can have a lifting stabilizer just by shifting the weight back or making some other adjustments. I did some glide tests with your Slow Hawk 1 and found that it would glide with some positive stabilizer lift, which reversed the steering just as you described for the small size robofalcon.

I totally agree that "it has little if any bearing on the engineering aspects of the flapping wing". That is all the more reason why I feel it is not a separate category of aircraft and why it is no less an "ornithopter" for having the tail provide some lift.

And you have just illustrated that a single machine can cross over the boundary between stabilizer lift, and no stabilizer lift, just by what you do with the controls.

Do you think the higher airspeed could be somehow reducing the pitch-down tendency of the bird? Maybe in the downforce mode, the wings are producing a large dynamic thrust in order to overcome the drag of the tail, and when it speeds up, there is less dynamic thrust and therefore the high thrust line no longer causes it to pitch down. I suppose having just the right CG or less body drag would make this switch more likely to occur. Did that robofalcon have a body shell on it?

[Patricia J B]

I think that dive behaviour says good things about the design of your orni's Sean :)

The explanation of that behaviour is not as easy as I first thought. Pushing the stick forward would give down elevator and would reduce the tail down force, possibly even change it to 'up ' force. So the tail would go up, the nose down and the orni would dive if the throttle setting was kept constant.
As the airspeed increased, the force on the tail would also increase [other things being kept equal, a stable aircraft tries to maintain the same angle of attack]......If the stick was held full forward, you would expect that the up tailforce would increase, the airspeed would increase, the dive angle would increase and the aircraft might even tuck under. If the stick was released [ ie: 'stick free'] just after entering the dive and allowed to do what comes 'naturally' , the aircraft would hopefully stabilize at the original AOA that it was trimmed for. If the stick was held in the neutral position after entering the dive, you would get yet another type of behaviour. Test pilots test all 3 and more !

I wonder if, when the orni reached a certain airspeed, the trailing edge of the tail deflected up or down and acted like a trim tab or possibly waved like a flag and caused the tail to lose the 'up force'.....or perhaps the tail was acting as the trailing edge of the wing and increased the wing's camber then as the airspeed increased the lift increased and the CP moved forward causing the orni to stabilize ??
Very interesting, has anyone else got any ideas !

Cheers,
Patricia

[Patricia J B]

Sure I'd be willing to say that if there is a second power source that it is not a pure ornithopter. I think the word "pure" makes the most sense in this context, and less sense in the context of whether or not there is a lifting stabilizer.


I totally agree that "it has little if any bearing on the engineering aspects of the flapping wing". That is all the more reason why I feel it is not a separate category of aircraft and why it is no less an "ornithopter" for having the tail provide some lift.

And you have just illustrated that a single machine can cross over the boundary between stabilizer lift, and no stabilizer lift, just by what you do with the controls.



Nathan, if you had been around at the time of the Wright's and the others , you would have nitpicked them completely out of their achievement ! :(

The problem with allowing hybrids to be called ornithopters is the fact [whether you agree or not] that most of the world thinks of orni's as being all-flapping wing. If the media then reports the successful flight of an orni, the public then thinks that pure flapping wing flight has been achieved and the public will have been misled. Most of the people who have actually done this in the past have been deliberately and fraudulently trying to fool the public into thinking that they have achieved the milestone of pure flapping flight. You are making it very easy for the frauds of the present and the future.

There has to be a method of separating the 2. Up until now, it has been the obvious and clear method of looking to see whether the aircraft has fixed wings, fixed/flapping wings or only flapping wings. Simple !
A fixed/flapping wing aircraft is not the same as an all-flapping wing scientifically or in any other way.

You obviously don't agree with the world's method of categorizing aircraft either !! Aircraft of the heavier than air type are categorized by the type of sustaining wing [ie: the actual surface on which the sustaining lift is produced] FIRST and THEN by the type of engine or thrust producer [if it has an engine].....so we have:

Fixed wing.....piston engine
Fixed wing.....jet engine
Fixed wing.....flapping thruster [Schmid]
Fixed wing.....no engine [glider]
Fixed wing.....rocket engine
Fixed wing.....human-powered

Rotary wing.....piston
Rotary wing.....jet

The above categories are used around the world to indicate that they are 2 different types of flight.

We also have the following [using the same method of categorization]

Flapping wing.....piston
Flapping wing.....other types of engine
Flapping wing.....human-powered

Combinations:

Fixed/flapping wing + jet assist..........UTIAS aircraft
and others throughout history.

These categories indicate the way in which the flight was achieved ie:

Fixed wing.....sustaining wing is fixed rigidly to the fuselage and is pushed or pulled through the air by a thrust producer of some kind and the thrust producer is then defined.

Rotary wing......sustaining wing is rotated at sufficient speed to produce the sustaining lift.....it is fixed to the fuselage by means of a rotating shaft. The means of rotating the shaft is then defined.

Flapping wing......sustaining wing flaps at sufficient speed and correct angle to produce both the sustaining lift and the thrust required. The method of flapping the wing is then defined. The sustaining wing is attached to the fuselage or airframe by means of either a simple or complex pivot or hinge which allows the flapping movement. It is not fixed rigidly as in a fixed wing. It does not rotate like a rotary wing.

To say that pure flapping flight isn't a separate category from the other two or from fixed/ flappers is to deny the obvious.

Schmid didn't achieve pure flapping flight. He wanted to though and he was halfway there when his experimenting stopped. He saw the difference between pure flapping flight and his fixed/flapper. If he had achieved pure flapping flight, I wonder how he would have felt to hear you describe such a wonderful achievement as being the same as a fixed wing/flapping wing combination. People have spent their lives trying to solve this problem [pure flapping flight] and you reduce their work to nothing. You are not helping either orni research or the historical recognition of flapping wing pioneers like Schmid. All you are doing is encouraging the frauds to waste time adding fixed wings and the like in the hopes of getting first orni prize in your competitions or of being recognized as the first manned orni instead of encouraging genuine flapping flight enthusiasts who will spend their time researching and experimenting with pure flapping flight which will lead to greater knowledge and finally.....successful pure flapping flight !

[NChronister]

"The problem with allowing hybrids to be called ornithopters is the fact [whether you agree or not] that most of the world thinks of orni's as being all-flapping wing."

Patricia, you keep saying that, but I have provided all kinds of documentation that shows a lot of people don't think of ornithopters as all-flapping. Probably over half of the old magazine articles in my file show models with some amount of fixed wing area and refer to them as ornithopters. I could scan more articles but I fear I'd be wasting my time since you don't acknowledge the evidence I've already presented.

Plus only 2 out of the 8 dictionary definitions I found were in support of an all-flapping definition. It may be safe to conclude that there has never been any *agreement* about the definition but to say there is concensus in favor of an all-flapping definition is simply unfounded.

"You obviously don't agree with the world's method of categorizing aircraft..."

I've already explained why ornithopters are different so you either didn't follow my argument or can't be convinced by reason.

"If he had achieved pure flapping flight, I wonder how he would have felt to hear you describe such a wonderful achievement as being the same as a fixed wing/flapping wing combination."

I didn't say it was the same. My position is that it should have the same name because the differences are of quantity, not category.

I'm not encouraging "frauds" and I really don't think anyone is interested in Schmid-type ornithopters any more. It is just a matter of historical recognition. But someone may be interested in using a lifting stabilizer just because it makes good design sense. To say it's not an ornithopter in that case is simply absurd.

You have stated that your support for the "no fixed lift" definition is not motivated by your desire to be the first to fly an ornithopter. Tell me, if that is the case, WHY do you want it defined that way, because you have not presented any kind of convincing support for the idea nor can I see any other reason why you would support it.

[NChronister]

Are these helicopters, Patricia?