Freewing concept

[tbass]

RC Gang,
Has anyone tried to absorb and model the "freewing " concept..?
Go to www.freewing.com to see the drone freewing idea if not familiar with
freewing. I can't seem to get my ming wrapped around the concept. Intriguing. Let's talk.
Tom Bassett WM2M

[Langenase]

Just finished of download all the information from the site you indicated. I didn't knew this concept but seems interesting for applications on RC models. I think that the Manta as it was built and tested in 1992-1994 would be adequated for easy of construction. Reading ready for tonight, you'll be guilty for robbing me my sleeping time!

Thanks
Jose Antonio

[Tom Harper]

tbass,

Interesting link. Seems like a lot of effort.

From the link:

"Thus it automatically adjusts to changes in the relative wind (e.g. gusts) just as weathervanes do."

I ain't gonna touch that!

[Sparky Paul]

tbass,

Interesting link. Seems like a lot of effort.

From the link:

"Thus it automatically adjusts to changes in the relative wind (e.g. gusts) just as weathervanes do."

I ain't gonna touch that!
.
Why not? :)
Just bolt your freewing to the roof of the barn and..............

[Tom Harper]

Or perhaps the door hinges.


tbass,

Forgive the inside humor.

I think the thing is neat. I'll have to look at the description again. What problem do they solve?

[Tom Harper]

Looked at the whole thing and it is definitely novel. The vectored thrust scheme looks more interesting than the bouncing wing idea.

Would vectored thrust be a productive approach to the ultimate slow speed model.

For an AP model that needs short take off and very low flying speed would it be reasonable to mount the engine at the CG and inclined at a positive 50 degree thrust angle?

Kind of a semi-heli.

[markdrela]

The Freewing system is effective in tail-sitter VTOLs which need to rotate to transition to horizontal flight. Example:
http://www.aurora.aero/GE50/index.html

[Jim_Marconnet]

Like Tom Harper said.

These two concepts are very interesting, individually and collectively. So.....

I'm hoping to see someone do something with one or both of them in R/C planes. But I have no idea what makes sense to try.

[Langenase]

Hi to you all

I'm making some sketches, but am in doubt about the following points:

1) "......A single jackscrew acts against a control horn on this torque tube to motor the booms (i.e. fuselage trim tabs) "up and down" during flight......"
Could a single standard servo (HS-422) accomplish this task or do we need another system? I cannot accurately figure how much torque do I need...
2) Do you think that from the mechanical point of view the all-moving cross-connected booms are a better solution than the Manta fixed central section with elevons and twin rudders?
3) High aspect wings or low aspect wings?
4) Vertical fins and squared stabs or V fins at about 110º?
5) Another question is the type of airfoil, from the images on the web it seems that the folks of Freewing employ something vaguely ressembling what appears in the drawing, with very small control surfaces, NACA65019? Wortmann family? Autostable?....airfoil itself has to have a strong positive pitching moment at trim. Help wanted.

I think that it should be easy to make a simple Depron version in the range of the 1200mm (47") WS, AUW around 20 ounces. Freewing could consist of a single CFT 6mm dia. acting as spar, bushed at the center body. Motor, maybe a Mega 16/15/3 geared 3.3:1 (lots of power to hover) fitted with a folding 9x7"/10x6", 45 mm cone, batt 3S2P 2000 mAh 20C, ESC Jeti Adv Plus 40...Unfortunately I'm away from home because of work, and for the moment cannot begin a new build, just make drawings and calculations....and dreams :)

[Langenase]

Visit:

http://www.freewing.net/movie_folder/movie_large.html

and take a look! :) :)

And here is the guidance system...FF9, laptop and joystick! :eek:

[Jim_Marconnet]

Visit:

http://www.freewing.net/movie_folder/movie_large.html


That's the best video I've seen on their products. It clearly shows the equipment and the angles between the various parts, something that had eluded me before seeing this video.

Has anyone contacted them about a R/C (kit?) version?

[feihu]

Here is a photo of a free wing using a canard to control the wing angle in flight. It was part of a study by NASA back in the '70s as a Gust Alleviation system, plus other factors associated with a free wing.
The model was a 60 size "Falcon" kit modified for the project.
And yes, you can see the wing flapping up and down in trubulence while the fuselage apparently remained stable. Scales on the fuselage and on the canard booms allowed visual readings of wing and canard angles in flight from the back of a truck. The model exibited good pitch and roll response, was aerobatic, and would not stall.
Fun Project!
feihu

[Jim_Marconnet]

Here is a photo of a free wing using a canard to control the wing angle in flight.....

Thanks for sharing the very informative photo. Now that we know how it can be done simply, the sky is not the limit!

I've been eyeing my Easy Star noticing how the two wing halves are connected together with a carbon tube that runs thru the fuselage. The canard they used is the "missing link" on how to modify an Easy Star to be unstallable. Looks like a project for a new ES kit instead of to one that already works! :D

[NeilDude]

This is really exciting. NOW I see the amazing potential of RC modelling. New aviation technologies can be demonstrated in a very responsive way.

Freewing has all the hallmarks of a great new design-it is simple. That Burt Rutan is a shareholder speaks volumes.

[Langenase]

Here is a photo of a free wing using a canard to control the wing angle in flight. It was part of a study by NASA back in the '70s as a Gust Alleviation system, plus other factors associated with a free wing......... feihu
Hi Feihu
Nice photo you sent. I cannot find any info at Nasa Langley Repository nor at Nasa Central. Could you please give me some information about DFRC 77-060 in order to make a more accurate search?
Thanks
Jose

[feihu]

Jose:

Go to www.nasa.gov/centers/dryden/home/index.html
Look for the Search Box and enter TM-72853

TM-72853 is a Technical Memorandum entitled "Flight tests of a radio-controlled airplane model with a free-wing, free canard configuration".

feihu

[Mister UHU]

Looks a bit like the Rutan SpaceShipOne thing,
even though the function is a bit different.

Apart from the claims,
do the Freewing aircraft really have practical advantages over normal ?

The NASA work was 30 years ago,
I would have thought if it was going to catch on it would have done so by now.

[feihu]

Mister UHU:

A couple of contractor studied were done using the free wing concept applied to a single engine Cessna. While the study concluded the concept could be operational, the technical gain would not be worth the R & D effort.

feihu

[Mister UHU]

Mister UHU:

the technical gain would not be worth the R & D effort.

feihu

This is what I suspected.

No "killer app" that absolutely needs this solution.

[Troy]

Mister UHU:

A couple of contractor studied were done using the free wing concept applied to a single engine Cessna. While the study concluded the concept could be operational, the technical gain would not be worth the R & D effort.

feihu

This is what was said about the Cessna:
For example, in the 1980s NASA sponsored an investigation to devise a technology to mitigate turbulence. The researchers began with a Cessna and conceived an active gust-damping system. On a long boom protruding from the nose of the vehicle there were sensing vanes. The researchers decided to install special servos on all the control surfaces, and even added some control surfaces that were altogether new. The idea was that the vanes would enter turbulence before the airplane itself, the quality of the gusts would be analyzed by onboard computers, and directions sent to all the control surfaces. The intent was, essentially, to dive down into upward gusts, up into downward gusts, etc., thus improving ride quality in bumpy air.

Did this system work? Sure. For this they paid a price of cost, complexity, safety, weight, reliability, and maintainability. How does a similar Cessna-size pivoting wing fare? At least as well, according to NASA CR-1523 of 1970.

Out of my own curiosity, I'm wondering if the aileron inputs are traditional and directly roll the plane or if they induce a pitching of the half-wing, in turn changing angle of attack and that rolls the plane..??

[feihu]

Troy:

I seem to recall, but don't remember for sure, that the control system was elevons as opposed to ailerons, and the modified flaps were used for gust-alleviation; and the elevators were used to trim the fuselage in flight.

feihu

[Langenase]

Jose:
Go to www.nasa.gov/centers/dryden/home/index.html
Look for the Search Box and enter TM-72853........feihu

Many thanks for your quick response. I did'nt look for it at Nasa Dryden, my fault!.
Bye :)

[Langenase]

Out of my own curiosity, I'm wondering if the aileron inputs are traditional and directly roll the plane or if they induce a pitching of the half-wing, in turn changing angle of attack and that rolls the plane..??
The practical applications that I've seen of the freewing concept (UAVs) use ailerons (elevons, ailevators?) for both roll and wing AoA control. Pitch control is made changing the attitude of the body (thrust vectorization) by means of aft control surfaces (sort of elevators but not acting as elevators, just trimmers). Some have rudder/s, others don't have. My project include rudders and elevators/trimmers in case you want to fly as a normal fixed body aircraft with free wings.

[Tony65x55]

I've been back and forth in my head on this one and I can't see what advantage the freewing concept has over a properly trimmed canard configuration besides thrust vectoring. As a canard enters a gust, the canard responds first by lifting the nose causing a increase in the AoA of the main wing and restoring equilibrium. Anyone who has spent much time with canards knows they are very good at dampening AoA changes. Can someone explain this to me?

Tony

[Langenase]

I've been back and forth in my head on this one and I can't see what advantage the freewing concept has over a properly trimmed canard configuration besides thrust vectoring. As a canard enters a gust, the canard responds first by lifting the nose causing a increase in the AoA of the main wing and restoring equilibrium. Anyone who has spent much time with canards knows they are very good at dampening AoA changes. Can someone explain this to me?

Tony
Well, I think the main advantage of the free-wing lies in his gust-alleviation capacity and hence the increased commodity (?) (apologies for my poor english) for the passengers, a canard in a wind gust should react very firmly. For me the main interest of this concept lies in the ease of vectorizing the thrust thus permitting STOL (almost VTOL!) capacities for an aeromodel :)
Jose

[Jim_Marconnet]

I have seen the recent discussions on the point of all this.

I personally hope to come up with a STOL and ustallable plane. If that's not possible, then I probably won't persue it further.

[Mister UHU]

[QUOTE=Troy]


the quality of the gusts would be analyzed by onboard computers,
and directions sent to all the control surfaces.


Did this system work? Sure.

For this they paid a price of
cost, complexity, safety, weight, reliability, and maintainability.

[QUOTE]

Not really suitable for small cheap home-built models $$$$$

[Langenase]

Not really suitable for small cheap home-built models $$$$$

But you're talking of another system!