FFFFW-Fan Fold Foam Flying Wing

[earthsciteach]

Here's a pic of what's left of wing #1 and the start of wing #2. Wing #1 has already been cannibalized by a friend of my sons' from the 'hood who is building the mini-glider in the top of the pic.

Bicyclemonkey-don't get me started on Airfield 800 mm's. I bought the Spitfire. What a frustrating airplane! So many minor issues that add up to foam carnage. It does look nice, though.

 

[jetpackninja]

Teach-
There are a couple different builders around here that take different but similar approaches to the same end.
Both of these guys sell kits, one uses 3 mil laminate on the wing surfaces and a carbon spar across the wing halves near the CG. The other one uses a 3/8 or 1/4 in spruce spar in a similar fashion but laminates the wing with lightweight colored packing tape. Both of these guys sell EPP combat planes and have achieved a very durable design.
crashtesthobby.com
extremewing.com

Well, FlyingMonkey....
I had a GREAT time flying the wing yesterday. But, bravado and gravity got the best of me, as they usually do. What appeared to be a repairable crash turned into, "I'll just start over."

I have started on Rev 2 of my flying wing. It is going to be carved out of a 2" thick block of very inferior foam. I spent a bit of time this evening trying to envision the final product from said block of foam. I also spent a good bit of time trying to remember how to fix the x and y axes to the same scale in excel so that I can print out the airfoil to scale in order to make a template for hot wire cutting. I haven't resolved either.

Once I figure out how to carve it out of the foam, I'll look into how I can give it a strong exoskeleton without adding too much weight. Glassing doesn't seem to work out well on this scale. I really should stop playing around and just build a real airplane. Stupid lack of money.

 

[earthsciteach]

Thanks, JPNinja. I have enough wood veneer to cover the wing. It will be beautiful if I go that route, but that will make me hesitant to slam into opponents. I am considering some lightweight options to cover the foam-random orientation fiberglass cloth and a thin coat of foam safe urethane, or simply covering in packaging tape.

I'm taking my time with this one. I know the airfoil profile I am using. Just need to make a couple of templates. After putting this much effort into it, I doubt it will be a combat wing.

 

[FlyingMonkey]

You're over thinking it, teach...

There's a few plans online for a folded flat foam wing, that has a full airfoil. They then use the spray expanding foam in the leading edge section, making it tough as nails, but still light.

It's a mean combat wing.

 

[jetpackninja]

Fred- was that you that posted about using dryer sheets and some kind of bonder (can't remember what) as a reinforcement material? Sound interesting. Do you have a link or two?

It's a mean combat wing.

Hahahaha- I'm DEFINITELY gonna have to find a way to make you back that statement UP!

 

[FlyingMonkey]

Yes, water based polyurethane.

I've seen pantyhose used as well.

 

[earthsciteach]

Yeah, I know I'm overthinking this. Its turned into more of an experimentation of methods and materials at this point!

 

[colorex]

WARNING! Off Topic!

Spoiler!

HAPPY 500th Thread!

 

[bubsteve]

they do fly well!!bubsteve

 

[earthsciteach]

Nice wings, Bub. Those things are just too damned fun!

I archived my last wing in the round file. Now, I'm making one out of 1" XPS from Lowes. It will have a blunt nose, sort of like a cow ray. The wingspan is 30". Max wing chord is 10". I plan on powering it with a 1200 kva motor swinging a GWS 9x5 prop.

That leads to a question. In combat, all other things being equal, would it be better to have top end speed, or lower end torque?

 

[jetpackninja]

When we fly combat what we attempt to do is fly in a large oval at low speeds. A lot of the flying gets done in a glide or half throttle. The technique that we use to get the most hits is to fly in almost formation, then when you are behind him, hit the throttle and try to hit him as you pass. Harder than it looks or sounds. Top end speed isn't what you really want or need. Good acceleration is what you are after.
We use the fc2812 emax motors a lot for this size plane with a 7x6 prop. $6 when HobbyKing has them in stock...

 

[ananas1301]

When we fly combat what we attempt to do is fly in a large oval at low speeds. A lot of the flying gets done in a glide or half throttle. The technique that we use to get the most hits is to fly in almost formation, then when you are behind him, hit the throttle and try to hit him as you pass. Harder than it looks or sounds. Top end speed isn't what you really want or need. Good acceleration is what you are after.
We use the fc2812 emax motors a lot for this size plane with a 7x6 prop. $6 when HobbyKing has them in stock...

Exactly! So rather more torque then end speed. Also on combat always keep in mind to have more then one wing. As a combat beginner you will see how good the others are and how hard it is to get someone down.

 

[F16V1PER]

Here's my first flying wing! Total build time was about 2 hours. Its a testament to the old adage, "If you have a big enough engine, you can make a barn door fly." My "plans" are at the nose-serious back of the envelope stuff!

The whole thing is pretty much encased with a packaging tape exoskeleton. aileron hinges are just packaging tape on top and bottom. Airfoil shape is almost non-existent.

I have 3 flights on it. The cg was too far back on the first one, so it flitted around like a butterfly until the inertia from the prop spun the nut off the threaded shaft. It then fell to Earth like a leaf. No harm done!

The second flight got off to a good start, but I over corrected on launch and hit the ground slightly nose down. It pitched the battery off.

On the third flight, I moved the battery slightly back and she flew like a twitchy fighter! Until, she threw the battery off and fell to the ground like a leaf. Fourth flight is coming up. I've taped the battery solidly down with layers of tape (sure, I have velcro, but why waste it?).

This wing is my combat fighter. She needs an adversary!

View attachment 753 View attachment 754

How well do you think this will work for FPV?

 

[earthsciteach]

I think a larger fan fold wing would be fine for fpv. You would need to be sure to have spars for support. I'd make a true airfoil instead of a flat K-F type. I'm working on a wing carved from 1" XPS foam. I've covered it in laminate (the kind from a laminating machine). I intend to use it as a combat wing, but I think a slightly larger one would be great for fpv.

 

[jetpackninja]

teach- what is xps foam? Expanded polystyrene?
look at planes from ExtremeWing.com and CrashTestHobby.com
The Extremewing uses spruce spars and reinforced tape
The Crashtesthobby planes use carbon fiber spars on the smaller wings and fiberglass rods on the larger wings

I did a variation of the fiberglass with a curve in the spar. The fiberglass is very flexible, to use it effectively you need to have one in the same location on the top and on the bottom of the wing.

 

[earthsciteach]

Yep, at least I THINK its XPS. I used the 1" rigid foam insulation board from Lowes. I'll attach a pic. Currently, I am working out placement of "stuff" for a decent cg. Looks like I'll have to cut the motor inboard a bit.

I did check out crashtesthobby. Very cool stuff on there. I'll also check out the other link you posted. Thanks!

Oh-The Mig is my newest plane-Sky Angel 50mm.

 

[earthsciteach]

I maidened the combat wing today. It is a ROCKET! She is definitely pitchy, but flies great! And she is fast! I taped 6 defunct AA batteries to the nose to get the cg right. I'll post an onboard vid tomorrow. She is a pleasure to fly!