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Old Nov 26, 2005, 07:10 PM
Foamy Season is here! MX2#1
pitviper51's Avatar
Elizabethtown, Kentucky
Joined Nov 2005
3,406 Posts
flying wing design

hi everyone
just got a set of epp wing cores not sure what brand. got them in a trade, im issue is that when put together the wing is almost straight, with a little taper on the leading edge, if i put the wing tips on the it like i do on my combat wing mini xe, or any similar, will it still work its kinda gonna be home design im looking to build it for slope light weight, any ideas.....
pv51 will post pics tomarrow
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Old Nov 27, 2005, 12:23 AM
Mr. Innocent's Avatar
Oceanside CA
Joined Dec 2004
4,046 Posts
Put a fin on it! Ditch the winglets, and do a search for "center fin" which should provide you with all the info you need to put one on the wing.
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Old Nov 27, 2005, 02:05 AM
Hello Moto
lockheed martin's Avatar
Auckland, New Zealand
Joined Mar 2005
605 Posts
Sorry but your discription was kinda vague... are you saying that the root chord and tip chord is pretty much the same lengths as you said there is little LE taper?
If so just round the tips with sand-paper and put a fin on the leading edge of the Root chord as Mr. I said.

The reason you dont need the wing tips is because the tip chord of the chores are very long, which means more cleaner flow of air over the tips therefore less turbulence and ultimatly very little tip stall. That is basically what winglets are for, to stop the air from rolling over the edge of smalltip chords cuaseing turbulence and tip stall.

But you still need some form of horizontal stability hence the centre fin/vertical stab.

Hope this helps...

p.s., if possible post a profile of the root and tip airfoil of the cores. You could try traceing an outline onto paper ect. That way we can see if the foil has got camber or washout ect which effects lift and stability ect.!

Ok,

Nick
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Old Nov 27, 2005, 11:55 AM
Foamy Season is here! MX2#1
pitviper51's Avatar
Elizabethtown, Kentucky
Joined Nov 2005
3,406 Posts
pics

heres a few pics, i have a plan to make a small fusealage to extend a few inches forward, and a few back past the te, i will put a vertical fin on thaat part , today im hoping to get the fuse cut out, the guy i got the wings from has used them for powered combat planes with v tail, but im alway up or a design challange, ill keep you updated on the progress
pv51
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Old Nov 27, 2005, 04:42 PM
Hello Moto
lockheed martin's Avatar
Auckland, New Zealand
Joined Mar 2005
605 Posts
arrrr i see what you mean. yer that looks similar to a disign of mine.

If you put a fuse on it, extend it forward of the LE more, but not very far back. Only far back enough so that the fin can be potted into it, like a moth. M60 fuse. The reason im saying this is becuase you wing cores are actually what is known as a 'plank' which is basically a straight TE and a pointed LE like they are. With planks, thier COG needs to be around 1/2 to 2/3 of the root chord back from the LE of the root chord, hence quite a 'rear' COG. What always happens is they become very very tailheavy as the COG goes WAY back, like almost off the plane. You need alot of corecting ballast on the nose to balence which makes the plane heavy.

So by haveing little fuse behind the wing and more infront, youll combat this tendancy of tail heavy planks and will only have to add a little correcting ballast to get COG spot on and will ultimatly come out with a lighter plane

Nick
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Old Nov 27, 2005, 06:02 PM
Foamy Season is here! MX2#1
pitviper51's Avatar
Elizabethtown, Kentucky
Joined Nov 2005
3,406 Posts
progress

got the wing glued up, thanks for the info lockheed, ill post a pic on the fuse once i get it cut out of the pink foam, heres a pic so far, i have monsterous ailerons for this thing should be fun to fly, if it works, also thinking about working rudder, i might try aerotowing with a slowstick haha, alos the histart i dea sounds fun, ill keep you updated thanks again for the info
pv51
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Old Nov 27, 2005, 06:07 PM
Crikey never leave beer behind
steve wenban's Avatar
Mt Annan Sydney Australia
Joined Dec 2003
23,416 Posts
Stick a centre fin in and go for it the section look great for a plank you dont need a draggy fuse take a look at a Red Herring or one of my Spades , yes they are a little
harder to balance but the performance when dialled in more than make up for it IMHO
SteveW.
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Old Nov 27, 2005, 10:15 PM
Foamy Season is here! MX2#1
pitviper51's Avatar
Elizabethtown, Kentucky
Joined Nov 2005
3,406 Posts
cool, i got the servo spots cut out, perfect fit, ill have the fuse cut tomarrow i hope, it wont be to big, just thick enough tto hide the battry pack , how would a working rudder do on one of these wings,, im wonderng if itll make it spin outa control,, wait... thats a trick hahah
more pics to come
mike
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Old Nov 27, 2005, 10:17 PM
Crikey never leave beer behind
steve wenban's Avatar
Mt Annan Sydney Australia
Joined Dec 2003
23,416 Posts
plans

spade and red herring to give you an idea
SteveW
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Old Nov 27, 2005, 10:22 PM
Foamy Season is here! MX2#1
pitviper51's Avatar
Elizabethtown, Kentucky
Joined Nov 2005
3,406 Posts
got the pm, cool pics, and plans, i may have to go that route, i got a ply piece between the wing core to mount the lauch hook, so il have to make a small fuse above the wing, but itll be similar to those design, how well do the fly in light lift??
pv51
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Old Nov 27, 2005, 10:28 PM
Crikey never leave beer behind
steve wenban's Avatar
Mt Annan Sydney Australia
Joined Dec 2003
23,416 Posts
the red herring loves light lift the spade is a med to big air machine
SteveW
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Old Nov 27, 2005, 10:30 PM
Foamy Season is here! MX2#1
pitviper51's Avatar
Elizabethtown, Kentucky
Joined Nov 2005
3,406 Posts
cool thanks, i hope i can get a day with northern wind, then my clubs landfill is great, unfortuneatly the prevaling wind is south southwest, do you know of any videos of the spade or red herring in flight.
pv51
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Old Nov 27, 2005, 10:47 PM
Crikey never leave beer behind
steve wenban's Avatar
Mt Annan Sydney Australia
Joined Dec 2003
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Pm'ed you
SteveW
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Old Nov 27, 2005, 11:07 PM
Hello Moto
lockheed martin's Avatar
Auckland, New Zealand
Joined Mar 2005
605 Posts
Man this is looking cool. How are you planning on attatching the fuse? Are you going to have a profile of the airfoil cut through the middle of the fuse so you can slide the wing through?

Nick

p.s. lol- if you have a digital radio dial the dual rates to 125% on ailiorons, get some speed and push hard left/right on the ailioron stick! you'll get some crazy snap rolls going on, especially with the large control surfaces!!!

Goodluck
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Old Nov 27, 2005, 11:12 PM
Feeling FrSky
surfimp's Avatar
United States, CA, Santa Barbara
Joined Feb 2003
20,091 Posts
I'd definitely go with a center fin as well, and I'd make sure to reflex the elevons. I have no idea what that airfoil is, but a reflexed flying wing airfoil it ain't. So you'll have to add the reflex via the elevons. Assuming you go with something around 1.5-2" wide for the elevons you should have very satisfying roll performance.

Make sure to extend the center fin 3-4" off the back of the plane if possible, and have some of the fin sticking down underneath the wing. Both of these things will add greatly to the yaw stability, in my experience.

Beyond that, having a small pod fuse can reduce the amount of lead you'll have to add to get the CG correct, but as SteveW notes it will add a bit of drag and possibly be an issue for durability (i.e. they love to snap off).

An underslung pod like the Weasel is kind of nice, because it's durable, you can land on it, and it will support your fin. But that's just one solution to the challenge, there are plenty of others. Good luck and have fun!

Steve
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