Delta design and build thread

[Tom Harper]

Just can't resist doing another Delta!

Outside of being terribly inefficent they are rugged, compact, easy to transport and really look neat in the air.

Great big Deltas fly best but they are difficult to haul around. I will go for a 6 sq ft area with a span of 55".

Experience shows that a Delta requires a minimum of 150 Watts per pound and 120 Watts per square foot of wing. A Norvel .40 is rated by the manufacturer at 1.4 HP ~1000 Watts. My Dyno tests indicate that Norvel's ratings are pretty good, but I'll derate it by 70% to be safe. So, that's 700W at the prop. With a weight goal of 4 pounds that gives me 175W per pound and 116W per sq ft.

Experience also shows that Deltas want the CG back about 10% of MAC. So the layout is essentially the same as the LD-4 with a Delta wing and the CG moved forward. I'll use the training wheels from LD-5 to avoid the trauma of early hand launches.

[DaveGherardini]

Hello Tom. Looks like another great project you have going there. I was wondering. Considering the types of planes youve built and posted a thread on. Do you have a big lake in your backyard with a Seawind or a Searay tied up to the dock?.. I look forward to checkin this thread from time to time to.

[Tom Harper]

Dave,

Nope, just a lot of desert and archeological sites that need photographing!

[Tom Harper]

Got most of the pieces cut out. Nothing glued yet.

Tapered the pylon to eliminate all of that lateral area in the prop wash.

Six inches of the pylon tabs into the wing and extends to the bottom of the lower fuselage. Think I'll recut the pylon to make it a little higher and to build the 4 deg of up thrust into the base. That's better than mounting the engine at an angle.

[alexcmag]

Your delta will be much more efficient if your motor is not so over the CG line and if you use a proper airfoil, like MH64, MH45, and so on.

[Tom Harper]

Alex,

Thanks for your suggestions.

Forgive me, I did not clearly state my design goals.

My application is aerial photography of archeological sites. These sites are in sandy, rocky areas with a heavy cover of cactus and creosote. Wind is a problem since I fly on mesa tops and near canyons. The model must carry a 13 ounce (camera and mount) payload and position it reliably over the target. It must then land in the creosote with minimum damage.

Conventional models with built up construction lasted one flight and were not repairable. I have found that Foam Board (paper clad foam) is inexpensive and durable. It is easy to repair or replace large sections. These models have a service life of three to six flights. Often the model is damaged when the wing catches a branch on landing. The Delta should be less prone to this problem - extending the service life.

The high thrust line allows me to place the camera out in front. The forward camera pod has easy access through the top hatch.

The design philosophy is driven by camera considerations, cost, transport and durability. Aerodynamic efficiency need only be adequate to keep the thing in the air.

[Tom Harper]

Too cold and windy to fly so made a good building day.

Redesigned the pylon and fitted the engine mount - mounted the ailerons - attached the pylon to the wing.

[biber]

On a delta there is not really the need for any fancy airfoil stuff. Since its AR is well below 5 and the LE sweep is most likely to be above 30°, there isn´t any 2dimensional airflow anyway. So common airfoils tailored for 2D flow aren't suitable, nor does anything more than a flat plate promise further benefits.

Tom, did you once try to get a plane down without major damages using a parachute? Maybe some work building such a rescue system, but could be a solution worth a try.

biber

[Tom Harper]

Biber,

Thanks for the comments.

Once in a while I start down the parachute path. It would take a sizable chute to lower a 4 pound airplane. The chute and it's bay increase weight and complexity. Add this to the fact that I know nothing about parachutes and I drop the idea after a few sketches.

For now I'll have to stick with a 'make em cheap and easy to repair' philosophy.

[Tom Harper]

Had some time today so I added the fuselage bottom, engine mount and stock balsa LEs.

Gotta go up to the big city tomorrow. I can get some poster board, an 8 ounce tank and a 2 1/2" spinner and that about does it. Supposed to rain and snow this week so I may finish this thing.

[Tom Harper]

Some of my CG assumptions were wrong. No big deal - just put the servos in the back.

Blocked in the pylon for strength. Adds some weight but I think it will pay off.

[Tom Harper]

Trimmed and sanded the pylon box. Installed and tested the electronics. Cut the camera bay and put in a bottom plate with a hole in it. Don't think I'll put any glass over the opening. Fit and glued the braces for the training wheels.

The CG miscalculation was a wrong guess on the CG of the bare structure and somwhere I got the idea that the engine weighed 11 oz instead of 15.5.

AUW goal was 64 oz without training wheels. I think it will come in around 70 oz. Acceptable.

[Tom Harper]

Almost done.

Weight with camera a full tank and the training wheels is 5 lbs 4 oz. That's 20 ounces more than I'd hoped but it's still 140 W per pound which should be more than adequate.

Might be able to fly it Tuesday.

[Tom Harper]

Oh yeah, the fins. Gotta add the fins.

[Tom Harper]

It's done. Probably have to get clear of the holidays to fly it.

[bobb15713]

Just an idea, have you ever considered using corrugated plastic sheeting for building? I've used it successfully in several planes, its very durable and cheap. You can search for SPAD on the forums for it.

bob

[Tom Harper]

Bob,

Thank's for the input.

I bought some (coroplast) and checked it out. I'm sure it is better for many applications. It is definitely stronger.

But, I dropped it because it is more expensive and much heavier than foam board. It is more difficult to work with and it does not bond with resin glue.

[Tom Harper]

One other construction detail. The wing is 1/2" thick but the elevons are 3/16".

With the controls in the up position I use a wood rasp to shape the foam to fair it into the elevons. Then the paper and foam are finished with sandpaper. The exposed surface is covered with clear packing tape.

[Sparky Paul]

I bent another forward looking camera yesterday. I won't be doing that anymore. :(

[Tom Harper]

Cringe - I've just started down that path.

How bad was it?

[Sparky Paul]

I'll find out when I see if the "protection clause" I purchased with the camera either fixes it or replaces it.
The plane did a piroutte around the lens on a touch and go... I hate it when that happens!
And the video which was supposed to be on wasn't! I hate it even more when that happens!
I was using a 1GB card specifically so I needed to turn the camera on just before launch, and leave it on.
Looking at what video there was it turned itself on the way to the takeoff point. Drat!

[karakoram]

Alex,

Thanks for your suggestions.

Forgive me, I did not clearly state my design goals.

My application is aerial photography of archeological sites. These sites are in sandy, rocky areas with a heavy cover of cactus and creosote. Wind is a problem since I fly on mesa tops and near canyons. The model must carry a 13 ounce (camera and mount) payload and position it reliably over the target. It must then land in the creosote with minimum damage.

Conventional models with built up construction lasted one flight and were not repairable. I have found that Foam Board (paper clad foam) is inexpensive and durable. It is easy to repair or replace large sections. These models have a service life of three to six flights. Often the model is damaged when the wing catches a branch on landing. The Delta should be less prone to this problem - extending the service life.

The high thrust line allows me to place the camera out in front. The forward camera pod has easy access through the top hatch.

The design philosophy is driven by camera considerations, cost, transport and durability. Aerodynamic efficiency need only be adequate to keep the thing in the air.

I am interested in Deltas as well, but I have a comment--it sounds like a large EPP foam wing would suit your needs better than depron/Fanfold/foamboard

[Tom Harper]

Karakoram,

I assume you are refering to foam core cut with a hot wire. That would make a nice Delta but it would not be fast and cheap. I have some Delta wing cores but I haven't used them because Foam Board has so many advantages:

Foam board is cheap and ready to use.

The paper clad makes it very strong

The paper is coated with a protective finish

It cuts with a razor blade and assembles with carpenter glue

Today was very windy so I stayed home and made another Delta. Started the design about 10 AM and got this far by 5 this afternoon:

[karakoram]

Hi, WHile I am interested in Deltas right now, I was actually referring to EPP flying wings, large enough to carry a camera setup. A Windrider QueenBee comes to mind. A friend of mine has one, and motorized it, and it can carry 2lbs of payload.

I usually fly EPP wings as my favorites, mostly due to crash resistance (we do a lot of combat).

CHris

[Tom Harper]

Thanks - gotta admit that I know nothing about EPP flying wings. Any pictures?

[karakoram]

Most of the wings now made are bouncable EPP. here is the forum

http://www.rcgroups.com/forums/forumdisplay.php?f=211

The queen bee that I refer to is in many threads. Here is but one (has pix and a drop box with a 2 lb payload)

http://www.rcgroups.com/forums/showthread.php?t=360060

[Tom Harper]

Thanks for the pics. That's a lot of airplane!

These two Deltas are a diversion from the design I've been using (LD4). I'm just curious to see if I can make them work in my application. Want to know if I learned anything from previous designs.

Maybe when these are used up I'll look into an elegant wing like the one you propose. Can you buy the cores? Is it glass epoxy or sheet covered?

[karakoram]

The Queen bee is a complete kit, except for motorization (motor mount, and stuff associated with a motor), as it was originally a sloper.

http://www.windrider.com.hk/products/product.cfm?id=9

What makes this plane (and other windrider products) unique is that they are MOLDED EPP instead of the usual hotwire cut EPP.

You cover EPP with colored packing tape, as in the pictures in that thread, or you use iron on. Packing tape is the preferred covering method for most wings. Easy to put on, cheap, lighter than iron on, and easier to repair after combat collisions.

You should not cover EPP with a hard covering like fiberglass or carbon fiber. This defeats the purpose of EPP wich is flexible. Epp is also impervious to 3m77 and 3m90 spray glue (get this at home depot), which is used to make the reinforcing fiber tape and the covering packing tape stick to EPP.

EPS (polystyrene) will melt with the above glues (due to the acetone in these glues), and is not flexible or bounceable like EPP, so we went away from using that stuff a long time ago (first generation wings were made of EPS).

EPS is rigid, and is what people use as cores for balsa sheeted, Fiberglass or Carbon airplanes. It is compatible with epoxy resins.

If you want foam cores, you can go here: http://www.flyingfoam.com/launch.html

They also have a large ready made kit of a flying wing: the mother ship http://www.flyingfoam.com/products.html

[karakoram]

back on Topic: How critical is the airfoil for a Delta?

Lets say I want to make a superfast delta, that can do 100 mph +
Lets say I want to get as close to possible to pylon racers, without going away from a delta.

Is fully symmetrical OK?

Is super thin airfoil OK (ie 7% to 4%) , or will it cause funny handling ?

Is reflex required, like flying wings need ?

[Sparky Paul]

40 years ago, deltas were the thing to have in AMA pylon racing, which dictated wing area. A .19 sized plane had 4 sq. ft. of wing, if memory serves.
48x12 for the usual Hershey bar wing.
Much larger than today's much faster planes.
Dale Nutter's "Sidewinder" was one of the fastest of the deltas in the early 60s'
I don't know what knocked them out of the slot.
Looking at the plans, Nutter used a modest amount of camber, and some reflex.

[karakoram]

forgot to add, I am doing this on electric power. Wing area helps with heavy batts.

using speed 400 size brushless (ie Mega 16/15/4 on a 6x4 prop, @550 watts is typical for me)

[karakoram]

40 years ago, deltas were the thing to have in AMA pylon racing, which dictated wing area. A .19 sized plane had 4 sq. ft. of wing, if memory serves.
48x12 for the usual Hershey bar wing.
Much larger than today's much faster planes.
Dale Nutter's "Sidewinder" was one of the fastest of the deltas in the early 60s'
I don't know what knocked them out of the slot.
Looking at the plans, Nutter used a modest amount of camber, and some reflex.

thank you that helps. I found this 1/3 way down http://www.rcstore.com/rs/general/listproducts5.asp?catid=44&catego=PL

I wonder, however, if more modern airfoils would make the sidewinder (or my own plane) faster ?

[Sparky Paul]

An AXI 2820/10 is approximately equivalent to a good .25 glow motor with the same prop.
In a Sidewinder, with today's light weight equiment instead of 10 channel reeds and Bonner Transmites.. it would be much faster than 100 mph, I'm sure!
Every delta I've made has crashed due to disorientation at distance. Which point is the front is a real problemd when it gets small and is covering ground! :)
I've flown what would be the old rules AMA pylon racer in the .15 size.. 3 sq.ft. of wing with 600 motors, direct and geared. They were pretty fast.
Brushless and Lipos would make them even faster.

[Tom Harper]

First I'll explain the picture. Carl made a left turn into the 10 AM sun. Bummer! When it emerged from the glare it was headed earthward.

Anyway it flys fine. The CG is too far forward. Caution on my part. Experience with Deltas says that's a lot better than too far back. The result was a longer than expected take off run. Once in the air it was extremely sensitive to elevon in roll. Pitch was gentle. Too much throw. The pitch was OK because of the large stability margin.

The high thrust line was OK. The model has a moderate flying speed and a steady climb. Everything worked great until the ground got in it's way!

[Tom Harper]

New front end in progress.

[Tom Harper]

Cut a new camera mount. This one is three pieces that will be RTV'd and taped together in hopes that the whole thing will stay around the camera in a crash. The repair has been easy. But, the wind is back up to the 40-60 mph range. So no flying for a while.

The second model is a scaled down version of the .40 Delta. Four sq ft, uses a Norvel .25. I'll use a lighter camera to keep the CG back where it belongs. Built this one while waiting for the glue to dry on the other one.

[Sparky Paul]

I'd go for a uncrunchable box with the foam inside for the camera, based on what the other one did. :)
Real ply instead of foamboard to keep the camera in the box, and let the foam do the shock absorbing.

[globemaster3c17]

Have you considered making a plane out of coroplast? SPADs are known for their durability and would probably fit your design goals well.

[Tom Harper]

Globemaster,

I bought some coroplast for comparison. It is very strong and can be curved. Definitely and advantage. The problems with it are practical. It is heavier than Foam Board and more expensive (2-3x for both). It is much more difficult the cut and bond than FB and it will not bond with resin glue.

I'll check it out again one of these days but, for now, FB seems to offer the best solution.

Thanks,

Tom

[Tom Harper]

Sparky,

Good plan, but think wrapping the outside of the foam with 2" glass tape will protect it. The FB blows apart on impact probably ejecting the camera. If it can stay inside of the foam rubber package it should just bounce around over the dirt. Kinda like the Mars lander.

In the crash below the camera squirted out bare and was laying under the airplane. It had lot of stuff in front of it that took the shock. The reciever and servos were toast. The camera itself is now in a plywood box so it is protected. My concern is that there is one or more crystals in the electronics. If one of those gets dinged, it's all over.

I'll see if there is enough room for a paper or plywood case around the foam rubber mount.

[Tom Harper]

Ready to go again. The camera mount is out for reinforcement - per above.

Engine is on another model for now.

[karakoram]

I read elsewhere on this forum that others have tried to make flying wings with Coro, but found it was too heavy. Not sure if that is correct, as I have seen really heavy wings fly ok (with enough power).

[HELModels]

Just a thought, but have you considered using 2 part polyurethane foam for your pod? The density is like blue foam but much stronger. You can pour into a mold made from your white foam. To keep it from sticking, cover the mold surface with monokote and light wax. It cures closed cell, so a molded shape wont have the crumbliness that people complain of polyurethane foam. It isnt until you cut into polyurethane foam, that little bits of foam get messy. Mixed exactly, it works.

[Tom Harper]

Electrostorch,

That's sounds like a good approach. I could use a plug for the camera space to avoid cutting. What would be the advantage of using foam?

[Tom Harper]

Karakoram,

Sounds like they came to the same conclusion I did. I can't really find any advantage to coro.

[Chas]

[QUOTE=Sparky Paul]
I don't know what knocked them out of the slot.
/QUOTE]

Rules!

Pete Russel was flying symmetrically aerofoiled deltas of many sizes at that time, and both he and Paul Telco who did a large .61 Vulcan found the CG much better at about half planform height.


C

[HELModels]

Electrostorch,

That's sounds like a good approach. I could use a plug for the camera space to avoid cutting. What would be the advantage of using foam?

What I was thinking was that you have already made a cacoon for your electronics. You could cast an almost indestructible one from the polyurethane foam. You could still use the soft foam for extra cushion.

I've messed around with the 2 part polyurethane a bit. I made a balsa servo box and poured some foam in it, with the servos installed, they have yet to come loose from crashing.

This stuff has a couple of advantages:
1) extremely strong
2) moldable
3) bonds easily to epoxy, resin, balsa, plastic, etc.

[Tom Harper]

Chas,

That's interesting. On a rectangular wing the null point is 25% of the Chord. That places 25% of the area ahead of the null point. On a Delta, 25% of the area is ahead of 1/2 of the base Chord. That makes sense.

[Chas]

Tom
I love to hear modellers talking about "null point", at last we are knowing what we're doing rather than the "balance on the main spar" religion of lore and myth!

I guess with conventional configuration we need a substantial margin of stability, which is why our traditional trimming practice has been to put the CG so far ahead of the AC (or aerodynamic centre, the null point as you say). But with deltas, I think the reflex allows a much closer approach of the two, and especially with tight proportional control we can get these two engaged if not married.

Paul's Vulcan was originally flown with the CG at 33% root chord, and it was leaden in pitch and needed tons of back stick. The engine (a Merco .61, about 650 watts) could hardly cope at this trim.

With 50% CG, to use the pilots own words, the engine "copes admirably with its task. The aircraft lifts easily and flies well with plenty of response to all controls.".

I don't know the weight of the aircraft unfortunately.

Good luck!

Chas

[Tom Harper]

Chas,

Looks neat!

I put a ballast box at the TE so I can rig the CG closer to the 1/2 C point. Mine are flat plate so the only reflex is the fairing from the bottom of the wing panel to the control surface ~5/16".

[Chas]

OK, great; flat plates are symmetrical, and at very low aspect ratios will fly at a wide range of alpha; CP shift should be easily accomodated. With CG right back the smallest of reflex will trim to an acceptable angle of attack.
Modelling has a weird history. Because in the early days everyone flew with "clutching hand", highly cambered aerofoils at very low Re, the myths sprang up about longitudinal stability "Holy Grails", so we had 30% tails, lifting tails, downthrust - all sacred cows (just start a thread saying that downthrust is crapola and you'll see what I mean!!) - it was ages before wind tunnel testing confirmed that even at model sizes and velocities symmetrical sections produced NO pitch change about the AC with variations to alpha. Even in 2006 it still hasn't sunk in.

"Place two 3/16th washers under the rear engine mounting lugs..." :rolleyes:
Cheers

C

[Tom Harper]

Actually this one has 4 degrees of up thrust.

Finished wrapping the camera mount. The camera is in a 1/16" ply box with an inch of foam rubber all around and fiberglass tape on three sides to hold it together in a crash. If it turns out that I should have used a box instead of tape I'll provide ample opportunity for he-hes and I told you sos.

[Mister UHU]

Interesting and unusual design.


As you don't have a smooth runway,
and are surrounded by rough scrub land,
have you considered a helicopter ?


I.C. engine or electric (smoother, less vibrations).
There are even some purpose built camera helis in production,
if your task requires something bigger or higher tech.


Also if you want to stick with a fixed wing aircraft,
have you considered trying the military method
of catching the model with a large strong net,
rather than trying to land it.


Cool project.


Please post some of your in-flight photos,
if you get your system working.

[Tom Harper]

UHU,

Thanks for the comments.

Helicopter would be a great solution but it violates some of my present goals. My goal is a a cheap, simple, inexpensive aircraft. These models cost under $10 to build. The paper clad foam is very easy to repair. I fear maintenance of a heli might be beyond me.

But, zipping across the desert with a fully equiped helicopter would certainly be spectacular.

We've (Carl Moore and I) been successful in getting photographs. Our present project is to identify the path of El Camino Real de Chihuahua in the area called Las Vueltas de Socorro. We are looking for wagon tracks from 1600 thru 1850. Lot's of dirt.

The other design we use is described in the LD4 build thread.

This picture illustrates what we get on a good day:

[Mister UHU]

TOP STUFF !


Good picture, looks like you have got your system to work.


Is it really possible to see a land feature from 150 to 400 years ago ??


So much of the worlds land surface has been altered in the past
century, that you must be in a pretty remote region.


You must have a very well tuned set of eyes to pick out this kind of detail.


As for the helicopter issue ;
TV companies, advert makers, movie makers,
Police forces, armed forces, etc, etc,
have all tried model helicopters for various tasks,
going back several decades.

I am sure you are more technologically able
than some of these users, so if they can
make a heli work, I think you could too.


Some modern RC helis seem to be pretty much Ready To Fly,
but are going to be more expensive than a basic airplane.
And there are the extra costs of gyros, fast servos etc.


And flying a heli and trying to take pictures at the same time,
is going to be more pilot demanding than flying a fixed wing airplane.


As for your choice of aircraft design,
it is quite daring, if I was in your place,
I would have started with a standard / trainer / cargo lifter design,
that was very stable in flight, able to carry a weight load,
have good flight duration, and have short take off and landing
capability.


I suppose once you have found the approximate place
where your area of interest is, doing more detailed surveying
is possible closer to the ground for higher resolution pictures.

But surely the quality of the camera lens is critical
for decent photos, with a SLR being the obvious choice ?


Sorry if I am stating obvious points.


Keep up the good work !


I will try to find the LD4 thread.

[Tom Harper]

Thanks for the comments.

Pressure tracks in the desert last 500 to 1000 years. I takes a long time for the bacteria and things to restore the dry soil. This area was very lush grassland in the 1800s. Late in the century the area was overgrazed by large cattle companies. When the grass was removed the Creosote moved in. So now it is Creosote covered desert.

Creosote will not grow in compacted soil. So it makes a good marker for wagon tracks. No Creosote means possible track.

We find a lot of artifacts from the last 1000 years. The indian structures we see from the air date from around 1100.

I started with an old free flight wing and a custom body. Then moved to a Sr. Telemaster. Good airplanes but they do not meet all of the criteria. The LD4 design is CHEAP (<$10), easy to transport, durable, hand launchable, good in wind and survives landings in Creosote. I can't ask for more.

[Mister UHU]

1000 years !


You must be in a very stable, untroubled part of the world.


Didn't the cattle make anything grow, with all their manure ?


My experience with humans is that they will take anything,
that isn't nailed down or locked up !


Hope you are taking good care of those Indian artifacts,
and they are going to a nice museum and being properly recorded,
or left safely in their original places.


If the land was previously lush grassland,
was this what attracted the Indians to the area,
and did they "hunt / gather" there ?


And did they move because of cattle ranchers,
environmental damage, or other reasons such as disease ???


I found a picture of the Telemaster,
and it seems a very solid design,
but as you pointed out isn't ideal for aerial photos,
because of the nose mounted engine,
fragile construction etc, etc.


Your foam creations are certainly more practical,
but are by no means thoroughbred flying machines.


I am surprised by your short rear fuselage / tail section.


But as your present airplane only just seems to fit
into your car, I suppose if it was any bigger you would
have to separate the thing into pieces.


The commercial military and atmospheric aircraft
seem generally to be motorized gliders,
i.e. high aspect ratio wings and not deltas,
but they are usually much bigger than your planes.


I have been using LiPo batteries,
and brushless outrunner electric motors,
and I can highly recommend them.


If you are using a 15 or 40 sized engine,
these can easily be replaced by electrics.

Which for aerial photography is great,
without the exhaust slime, vibration,
corrosive fuel, noise, starting hassles,
and ability to turn the motor off/on at will
many times, etc.


You seem to be having lots of fun,
I can think of many worse jobs to do !

[Tom Harper]

UHU,

The artifacts stay where they are found. None are removed.

The people who lived here in 1100 were later absorbed by the pueblo people in the 1400s. Their pueblo ruins are also in the area but I haven't photographed any yet. In 1680 there was a pueblo revolt. The Spanish were killed or evicted. Some people (Piro) from here went south with the Spanish. The rest went into the mountains to live with relatives.

The short coupling is not a problem. It just requires a slightly larger stabilizer. Lot's easier to build!

[Sail 'n Soar]

40 years ago, deltas were the thing to have in AMA pylon racing, which dictated wing area. A .19 sized plane had 4 sq. ft. of wing, if memory serves.
48x12 for the usual Hershey bar wing.
Much larger than today's much faster planes.
Dale Nutter's "Sidewinder" was one of the fastest of the deltas in the early 60s'
I don't know what knocked them out of the slot.
Looking at the plans, Nutter used a modest amount of camber, and some reflex.


Sparky, 4 sq ft (576 sq in) was the minimum wing size for a .15 sized AC. The .19 sized AC had something like a 786 sq in min area requirement. The deltas took over the event because they dropped all the added drag of a fuselage and conventional tail assembly. At race speeds induced drag was small compared to profile drag and the larger average Reynolds numbers for the delta's larger cords probably gave them an advantage there, offsetting the slight induce drag penalty, so which configuration had the lower induced drag at a given speed could be debatable. Without fuselage and tail, the delta's probably also had a lower weight advantage, also. A few months back, Model Aviation presented a construction article for an electric version of one of the classic AMA pylon racers.

[Mister UHU]

Hi Tom,

Sorry I am rather ignorant about this part of the world, and its history.

Spain is a hell of a long way from New Mexico.

But from what is visible today, surely it must be difficult to tell how it was created,
by whom, and in what circumstances ?

Taking photographs from hundreds of feet in the air can only identify large features,
while it is DNA, and other microscopic evidence that can valuable too.


Have you settled on your final aircraft design ?
Or are you still developing it and experimenting ?


Happy flying.

[Tom Harper]

UHU,

I am using the Creosote Cruiser design that I posted on the Aerial Photography board. It is performing very well and I posted some photos there.

We are looking for tracks from the El Camino Real. There is plenty of written history so we know the origin of old N-S trackways in this area.

Deltas are fascinating and I think offer some advantages so I will keep building. An advantage of Foam Board is that you can do a lot of experimenting with a small investment in time and money.

[delta400]

Experience shows that a Delta requires a minimum of 150 Watts per pound and 120 Watts per square foot of wing. A Norvel .40 is rated by the manufacturer at 1.4 HP ~1000 Watts. My Dyno tests indicate that Norvel's ratings are pretty good, but I'll derate it by 70% to be safe. So, that's 700W at the prop. With a weight goal of 4 pounds that gives me 175W per pound and 116W per sq ft.

Experience also shows that Deltas want the CG back about 10% of MAC

I would like to say a few words about the statements above.Over the past 4 Yrs. or so,I've designed over 15 different Deltas.My experience has shown that 1:they seem to require about the same power per Lb.as any other aircraft.I've flown with power levels of as little as 80W.per Lb. with good performance.With 100W.,they have excellent performance,and with 125-150W.,they are absolutely a Rocket!2:As for the ballance thing,I've found that 18% of MAC is the best place to start with,and most are nose heavy at that point.Almost all my Deltas fly great at about 20% MAC!Sorry if I misread you,but if your setting your planes up at 10%,yhen no wonder you need so much power and a ton of reflex on the elevons.Also any aircraft with such a foreward CG. would be "terribly inefficient".Just my 2 cents :D

[Tom Harper]

Delta,

Thanks for the comments.

The watts/lb numbers I used were for large models (14sq ft) models that did have 'rocket' like performance. They were flat plate and did not require an unusual amount of up rigging for reflex.

I did find that they required a forward CG. It could be that my calculations are wrong.

The Deltas have been on hold since the weather turned good. Been out getting some AP. I'll use your numbers as starting points for my next flights.

Thanks.

[Mister UHU]

UHU,

I am using the Creosote Cruiser design that I posted on the Aerial Photography board. It is performing very well and I posted some photos there.

We are looking for tracks from the El Camino Real. There is plenty of written history so we know the origin of old N-S trackways in this area.

Deltas are fascinating and I think offer some advantages so I will keep building. An advantage of Foam Board is that you can do a lot of experimenting with a small investment in time and money.



**************************************************


Hi Tom,


Nice name "Creosote Cruiser".


When you say ORIGIN, do you starting point ?,
first route ?, naming ?, usage ?, or what ????


What is the language of the written records,
Spanish, or even native Indian ???


And why were people writing about a road ?,
I am surrounded by roads and I never write about them !


I think deltas are cool !!


They are sleek and fast looking, even when they are parked on the ground.


Yesterday I bought a small Depron delta kit that I am going to thrash around indoors, I am tempted to fit a more powerful motor than it was designed for,
but I think I will delay this, until I have some flight experience with the weaker motor.


I view deltas like agile "sports cars",
while I think aerial photography really needs a "van".


One of the few full-size examples of a weight carrying delta,
was the UK Vulcan nuclear bomber of the 1960s,
but more conventional designs such as the B-52 have out lasted it.


Foam is a great prototyping medium,
fast to build with, cheap, tough, soft to cut,
and doesn't require finishing with tissue & dope etc.

But it is a bit heavy, and doesn't work as easily as balsa.


Yesterday in the model shop, a guy was talking about a in-flight video system, I WANT ONE !, but it will have to wait until I have done some other projects, and spending more money is naughty.

[Chas]

The Vulcan was designed to deliver Britain's "stand-off" nuclear bomb from very high altitude; later tactical developments made them camouflage it for avoiding detection from above (!!) because they expected it to deliver weaponry at extremely low level. It says much for the versatility of the design that it was quite capable of being thrown about hugging the German terrain, although at subsonic speeds this enormous aeroplane could be brought down by an Ivan with a pistol.
Still, the Germans were using Starfighters, sort of delta planform, as allweather low level interdiction aeroplanes about this time; save a buck and lose 200 pilots.
Apparently a standing joke in Germany at this time was:

Q. How do you get your very own Starfighter?
A. Buy a plot of land, and wait.

C

[delta400]

Tom,I went back and re-read my post and found a typo concerning the CG.I stated that 18% was a good starting point and that is wrong!That's where I usually end up before moving to max aft balance pt.The correct starting pt. is 16% MAC.I've gotten so used to balancing these Deltas that I usually start at around 17% and move aft from there,but for starters you should use the 16% figure unless you have a lot of experience trimming them to max comfortable performance.The further aft any plane is balanced,the more aerobatic and efficient it will fly--TO A POINT.Well,you know that,so I'll chime-out here-sorry for the typo.
Good luck&happy flying,Rich K.

[Mister UHU]

The Vulcan was designed to deliver Britain's "stand-off" nuclear bomb from very high altitude; later tactical developments made them camouflage it for avoiding detection from above (!!) because they expected it to deliver weaponry at extremely low level. It says much for the versatility of the design that it was quite capable of being thrown about hugging the German terrain, although at subsonic speeds this enormous aeroplane could be brought down by an Ivan with a pistol.
Still, the Germans were using Starfighters, sort of delta planform, as allweather low level interdiction aeroplanes about this time; save a buck and lose 200 pilots.
Apparently a standing joke in Germany at this time was:

Q. How do you get your very own Starfighter?
A. Buy a plot of land, and wait.

C


**********************************************


When I was a kid I used to admire the Vulcan and its shape,
now with hindsight it seems a bit odd and out of place,
but it was quite a vice-less plane compared to the Starfighter !


As for the dreadful Starfighter and its terrible death toll,
I think it was a result of the corruption and incompetence that was rife during the Cold War.

The makers of the Starfighter, Lockheed, were involved in a big bribery scandal that bought down several high-ranking politicians.

The USAF bought loads of Starfighters, and didn't want to believe that a big military contractor, and the government procurement structure,
could get things so badly wrong.

Pilots were being killed on a virtually weekly basis, but the powers that be refused to admit that there was anything wrong with the plane,
the dead pilots were blamed again and again, which I think was shameful.

The fact that a plane crashing itself and killing its crew was no good as a fighting weapon should the Cold War ever turn "Hot", didn't seem to cross the minds of the bureaucrates, or bother them one bit.


Ah, happy days, eh !


I think the Soviets were also guilty of many technological cock-ups and cover-ups, Chernobyl comes to mind, and the mutant Tu-144 "Concordski"
gracefully falling out of the sky and into the ground at the Paris Airshow.

Models seem very harmless by comparison !

[Sparky Paul]

The Italians didn't have the problems with the F-104 that the Luftwaffe had..
And had F-104s still in service not too long ago.
The Luftwaffe destruction rate wasn't due to the airplane's peculariarties so much as to the way it was being used.
http://www.fencecheck.com/forums/index.php/topic,2080.0.html

[Chas]

Yes Sparky that's what we're saying. The Starfighter was designed to get up high (like, HIHH!!) - Fast - and shoot down a bomber or two. Never low-level sorties. The English Electric Lightning was the same, but fared better with its greater wing area at low level (and the RAF never attempted to use it as an MRCA anyway).

The Italians - well, they are used to Ferraris. :D

Chas

[Mister UHU]

Yes Sparky that's what we're saying. The Starfighter was designed to get up high (like, HIHH!!) - Fast - and shoot down a bomber or two. Never low-level sorties. The English Electric Lightning was the same, but fared better with its greater wing area at low level (and the RAF never attempted to use it as an MRCA anyway).

The Italians - well, they are used to Ferraris. :D

Chas


************************************************


I don't really want to get into a big discussion about the Starfighter.

It was designed about 50 years ago, for a strange political situation that existed at the time.

Tom Harper started this thread to discuss his delta, and his AP project.
I would prefer it if he OKed this warplane diversion before I proceed further down this path.



As for the previous comments about the Starfighter : ---


If I wanted to be a smart-ass I would remark that obviously if you are thousands of feet in the air you are less likely to hit the ground !

The Germans had Porsches, (and BMWs, and Mercs) !


The battlefield is an unpredictable place, there are many examples of weapons systems being used in ways that their designers never expected.

As an airplane that could likely get damaged in combat, it would have been good design practice if the Starfighter had a greater safety margin, to aid its survival and continued fighting capability.

Just as the British SA-80 rifle is unreliable, and the antique AK-47 is a much more effective fighting tool.

Sports equipment is often the same, its no good having a fast racing car, if it keeps on breaking down, and won't get you to the finish of the race.

An aircraft should be easy to fly, it should become a natural extention of the pilot. In combat there is enough going on to keep the crew busy without having to worry about the airplane too.

In WW1 and WW2 many of the aircrew were kids with little training or experience, it is unrealistic to expect combat crew to be as capable as test pilots.

The famous tests at the Miramar "Top Gun" school proved that an expert pilot in a lesser plane can beat a novice in a state-of-the-art plane.

It isn't just about having the latest technology,
its about the usability and usefulness of the equipment.


Tom please comment.

[Tom Harper]

'fraid you're way out of my league. The closest I ever got to a fighter was maintenance on F-100 simulators - analog computer.

[Chas]

UHU, Kind of a rambling post..I can't make much of it.

All we're saying, and this was specifically to highlight the handling qualities of delta planform aircraft like the Vulcan or Starfighter, is that they rack up the drag to dangerous levels when thrown about at low level. The Vulcan got away with it because it was HUGE and the loading was low; the Starfighter was much closer to the ragged edge and bit very hard when pressed into a role for which it was never designed.

The concept and design, not to mention the execution, of the Starfighter was absolutely brilliant. A formidable aeroplane; a World Record holder; a potent adversary, within its design brief.

C

[Mister UHU]

I guess Tom doesn't mind this side-ways diversion too much ?


Sorry if I wasn't very clear.


The Cold War, and the "Military Industrial Complex", are very emotive topics for me.

Having had past encounters with government suits,
I have very little time or respect for most of them.


I don't think the problems with the Starfighter were limited to its high wing loading,
I think that there were some fundamental design mistakes made.

I totally disagree with you about the Starfighter being in any way "brilliant".

I think any good performance was most likely due to its engine thrust.

The graves of the many dead pilots speak far more eloquently than I will ever be able to.


As a somewhat contemporary plane, also sort of delta-ish, I much preferred the Phantom.
It provided years of service in many different climatic conditions, and in many different roles including marine use.
A solid, reliable, work-horse, that wasn't tempermental or a prima-donna.

A much better example of good design in my opinion.

Go on Chas, shoot that lot down, if you can !

[Chas]

No shooting from me mon ami! :)

The Starfighter was brilliant for what is was designed for - high altitude interception. That was it.

It went up like a rocket, delivered a missile or two against the Bears, and was able to belt back down to re-arm and get back up for another shot. It held World records for Altitude, Speed, Rate of Climb, etc.

If the aircraft is then pressed into a low-altitude role - well no wonder some limitations showed up. The Phantom was very versatile, again simply because of its lower wing-loading vis-a-vis the Starfighter, and was able to dogfight with MiGs or hug the NATO terrain with equal capability. I guess the Lightning was somewhere between the two in its flexibility.

Apart from the high wingloading, itself only a problem in low-level manouvering regimes, what aspects of the Starfighter do you think were deficient?

I'm with you on the suits! ;)

Chas

[Sparky Paul]

The F-104 was termed an "airfield perimeter defense" plane. Without external tanks its endurance was pathetic.
In the few instances it engaged in air-to-air combat, it lost, both in the Indian-Pakistan war and Vietnam.
OTOH, the MiG-17 and -21 did superbly.. when the USAF and USN first encountered these, the Migs would usually win.
When the US got ahold of a MiG-17 and began disimilar air combat training, the US pilots -always- lost in their first encounters.
Only by exploiting the superior aspects of the US fighters,... mainly by keeping out of the regions where the MiGs were good.. below 475 knots, could the US pilot control the engagement. The -17 having cable controls lost manuverability above 475 knots, and was poor in the vertical.
The -21 could turn, but lose too much energy turning.. and its gunsight was extremely poor..
Here's a site which has some interesting stuff on this...
http://area51specialprojects.com/havedrill/Project_Have_Doughnut_Tactical_files/fullscreen.htm
http://area51specialprojects.com/havedrill/Project_Have_Drill_Tactical_files/fullscreen.htm

[HELModels]

the US pilot control the engagement.

Doesnt matter what the arena, got to play your own game, not the opponent's. When your game is a winning one, you stick to it.

Tom,
How is your protective cacoon working? I used that "nasty" 2 part foam stuff again on my project and crashed again. Everything is still intact.

[Chas]

Hmmm...there is this....

In June of 1958, English Electric test pilot Roland Beaumont test flew an F-104A. He was quite critical of the Starfighter. He found the aircraft to have inadequate directional damping, evidenced by a persistent low-amplitude short-period oscillation throughout most of the flight regime. The use of a thin, highly-loaded wing had a severe adverse effect on the turning maneuverability. There were excessive break-out forces of the power-controlled ailerons. At high angles of attack, the high-set stabilator would tend to stall in the wing downwash, and a departure into a flat spin was often the result. Recovery from such a flat spin was usually possible only if there was sufficient height so that increased engine power could be applied to accelerate the aircraft back into controlled flight. Beaumont found that subsonic handling properties were unpleasant and particularly dangerous in take-off and landing configuration and were not compatible with bad weather operation. He predicted that the F-104 was likely to suffer a high accident rate in operation.


C

[biber]

Maybe I missed something, but there is no delta wing on the F-104, right?
I just see a very low AR.

biber

[Sparky Paul]

Doesnt matter what the arena, got to play your own game, not the opponent's. When your game is a winning one, you stick to it.

...
.
Yes! Don't take the other man's bet.. and don't fight his fight!

[Mister UHU]

Hmmm...there is this....

The use of a thin, highly-loaded wing had a severe adverse effect on the turning maneuverability.

There were excessive break-out forces of the power-controlled ailerons.

At high angles of attack, the high-set stabilator would tend to stall in the wing downwash, and a departure into a flat spin was often the result.
Recovery from such a flat spin was usually possible only if there was sufficient height so that increased engine power could be applied to accelerate the aircraft back into controlled flight.

Beaumont found that subsonic handling properties were unpleasant and particularly dangerous in take-off and landing configuration and were not compatible with bad weather operation. He predicted that the F-104 was likely to suffer a high accident rate in operation.


C


I'm not an expert on the Starfighter, and I don't want to become one.

Yesterday I did some background browsing on the web, and the general concensus was that the Starfighter was manageable if flown in a straight line, but hated turning corners, which is a bit of a problem if you are trying to dogfight !!

Also, if stalled it was a pig to try to recover.

To add insult to injury, the early planes had a downward facing ejection seat (I'm not making this up !), because with upwards ejection there was a danger of the pilot hitting the tailplane.

The Starfighter was relatively cheap compared to other fighters of the period, so appealled to countries with tighter government purse strings. Add to this the "effective" sales tactics of Lockheed, and its export sales become more understandable.

But with all the many modifications necessary to make it more usable, added to the costs of ownership, the Starfighter was much less of a bargain.

The nicknames given to the Starfighter (sometimes by its pilots) are a testament to its violent flying characteristics : ---

THE WIDOW MAKER
THE FLYING COFFIN
THE WICKED ONE


The Phantom also got some world records.
During the 1950s, and 1960s, aeronautical technology was changing so fast that new world records were being set nearly every month.
Any new plane that wasn't breaking records wasn't an advance on the state-of-the-art, and therefore would stand much less chance of military success.

The total cost of ownership must include the costs of pilot training.

The more sophisticated the airplane the more pilot training that is needed.

This is one of the reasons why the early MIGs were so effective,
basic flight controls that a farmer's son could easily master.
And why a basic airplane is more suited to third world operation.

Nowadays the Hawk is a popular choice for less developed countries, it isn't state-of-the-art but for its users it is at a basic enough level to be effective.

In modelling rubber bands are still used to hold planes together,
not very high tech, but still very effective.

[Chas]

Well, that was a quote from the Lightning pilot, and who am I to disagree with that?

Starfighter was originally a lightweight alternative to the Thuds, but by the time it came into service the front line squadrons didn't want it and they passed it over, where the interdiction roles came in. Just looking at it you could tell it weren't no dogfighter.

C

[Mister UHU]

Just looking at it you could tell it weren't no dogfighter.

C


A common phase describing the Starfighter was,
"man on a missile".

Which I think is quite accurate.

In the previous posting I was a bit inaccurate,
I wrote if a plane wasn't breaking records it was unlikely to be militarily successful. When I really should have written,
the development of a new design, is much more likely to be funded and bought by a major superpower like America, if it is capable of breaking records.


The links supplied by SPARKY PAUL show US military combat flight tests from around 1968, and show just how deadly the early MIGs could be.

Despite its high speed and fast rate of climb, the Starfighter wasn't able to easily defeat these planes.

For a really innovative piece of aeronautical engineering the UK Harrier is hard to beat.

[Chas]

For a really innovative piece of aeronautical engineering the UK Harrier is hard to beat.


In every sense of the term UHU! A first class piece of kit and it shows what the Brits can do.

Interestingly, vis-a-vis the Starfighter, the USMC have had a zillion crashes tryng to fly the Harrier! :eek:

Apparently tactics for Starfighter pilots against MiGs were very much like those of any outclassed dogfighter (eg the P40 against the Zero) - use your height and speed, zoom in for a quick rataratattat, and get out and back up high again if you can. Don't mix with 'em!

(Not that I'll ever get the chance)
Cheers
C

[Mister UHU]

In every sense of the term UHU! C


I'm not sure what you mean ?
I have taken my forum-name from a glue company that sponsored a kids model glider competition years ago.


I don't know about the USMC crashes.
The Brits have crashed a few, but not that many.
The Harrier proved more successful in combat in the Falklands than expected.

I think the UK Harrier pilots are very carefully selected.
Maybe even having helicopter experience ?????

I know the Americans have re-designed some of their Harriers,
and I can't understand why. Why buy something to change it ?


Some of the latest US fighters are VTOL.
They are only about 40 years behind the Brits !!!!

[Chas]

"Hard to beat". That's the Harrier (as the Fuerza found out).

I still have a precious tube of UHU Hart; still great for ABS hulls and 25 years old!

Chas

[Mister UHU]

I still have a precious tube of UHU Hart; still great for ABS hulls and 25 years old!

Chas


Yes that's the firm.

25 year old glue sounds very dodgey, surely it must have gone solid by now ?

I thought UHU Hart was their Balsa glue,
I didn't know it worked for ABS.

But I always thought ABS was a bit cheap and fragile.
As an RC car part it usually got broken pretty fast.

Do you like my forum-name ?

Maybe not very glamourous ??

[Chas]

Forum name is great, although my understanding is that Rolls Royce (of the Silver Wraith, Silver Cloud, etc) were deterred from selling a Silver Mist in Germany. :eek:

My Hart is still beating strong, although my missus was confined to her basement cell for using some to mend some pottery. Incredibly, it still works fine. Smells of balsa cement - luvverly!

I don't like ABS myself, which I guess is why my glue has lasted so long! I bought it for a Graupner "Marina" boat, decades ago, and now there are better ABS adhesives anyway, but some jobs really call for the slow set-up and slight shrinkage creep of the Hart (eg., mending tissue tears). Almost all gone now though!

Cheers
Chas

[Mister UHU]

Thanks I'm glad you like the name.

I don't understand the RR reference.

Did you know that RR (cars only, not jet engines etc) was bought by BMW of Germany,
so I guess their naming policy will probably get very teutonic with code numbers etc ??

Amazing pre-historic glue still working !!

Yes, bad missus, not only did she use some of your precious glue,
she tried to stick pottery with balsa glue and not special CA china glue !

I saw the "Marina" in the glossy Graupner catalogues that I used to buy every time I went to Germany in the 1970s.
Looked a nice well kitted cabin cruiser.

I was more into high speed racing boat designs,
but because the only batteries available at that time were NiCads the boats tended to be very heavy,
(and the batteries expensive) and the speed controllers very crude,
eg resistors or servo switches, modern electronics are a big advance.

Aerial photography / deltas / modelling science are somewhat more technical than a Graupner "Marina".

[Chas]

Yes until recently I had a "Bob's Motor Board", a spiral type pc board pattern that clipped over the servo to switch in various resistances - great boat heater! I could never bring myself to use it, even then.
I still have the Marina too! Nice boat - it's as technical as you want to make it. It was designed with modelling science, and the modellers of those days would be more likely to knock up a home-made receiver circuit than those putting silicon chip cameras into their parkflyers today. But whatever, it's all great progress.

Happy gluing! Chas

[Mister UHU]

Happy gluing!


Thanks, recently I have been trying a bunch of glues,
eg various CAs etc, and quite a few don't perform as well as claimed on the product labels, and some smell really horrible !
But if you use high tech plastics, and want high performance glues, you have to accept some industrial strength chemistry.

I don't think I ever saw anyone use a homemade receiver,
I guess the nearest was a guy at my old car club that made his own ESC,
but these were far from "home made", in fact they were made to a professional standard, and were of world class quality. Most of the top racers used them (unfortunately to beat me !), but in car racing the results depend a lot on spending money on the latest equipment.


Glad you still have the Marina, I think Graupner would be very happy.
In 2005 they celebrated their 75th anniversary, they are now into their 3rd generation of Graupner at the helm, very solid business.

Why didn't you use the boat heater ??
Did you find a better ESC to use ?

[Mister UHU]

ALL CLEAR !

Hey Tom I think its safe to post again.

Looks like me and Chas have bored everybody else away !!

[Tom Harper]

I've been working on other projects. The two Deltas are finished and waiting for a good flying day. Should do it soon.