Pizza Box X 2 ???
11-26-2002, 11:04 PM
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Pizza Box X 2 ???
Hey, check this out!
I built a Pizza Box, with two wings. They are 24" wide, side to side, and 20" long, front to back, with a 4" stagger making the total size 24" X 24".
The wings are 2 1/2" apart.
The elevons are hinged at 4" on the bottom wing only.
The CG is 6 3/4" from the LE of the top wing.
TT.42GP engine. 4oz fuel tank. Full size radio and servos, with a HS-81 on throttle.
Ok, it does fly but it has some problems.
It likes to climb and it likes to roll over inverted, alot.
Is that because the CG is to far back or should the stagger of the wings be changed.
I tried to move the CG closer the front but that is as close as I could get it without making longer motor mounts to get the engine out front more.
The engine mount is about 1/2" above the bottom wing.
Any thoughts or ideas?
Tim
I built a Pizza Box, with two wings. They are 24" wide, side to side, and 20" long, front to back, with a 4" stagger making the total size 24" X 24".
The wings are 2 1/2" apart.
The elevons are hinged at 4" on the bottom wing only.
The CG is 6 3/4" from the LE of the top wing.
TT.42GP engine. 4oz fuel tank. Full size radio and servos, with a HS-81 on throttle.
Ok, it does fly but it has some problems.
It likes to climb and it likes to roll over inverted, alot.
Is that because the CG is to far back or should the stagger of the wings be changed.
I tried to move the CG closer the front but that is as close as I could get it without making longer motor mounts to get the engine out front more.
The engine mount is about 1/2" above the bottom wing.
Any thoughts or ideas?
Tim
11-27-2002, 12:34 AM
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Pizza Box X 2 ???
I'll leave the CoG question for the PBF experts but it sure seems too far back to me..... But it's only a few percent compared to the 5 1/2 back on a stock'er.
BUT...... 4 inch separation on a 24 inch wing is not going to work worth a hoot. The air is just going to be way too confused in that small gap. In fact with the stagger you're looping over might just be due to the slot effect you've got going.
If you want to try a bipe what about increasing the gap to about 10 or so inches (12 would probably be better) and use a pylon'y thing to mount the engine right in the middle between the two wings. Couple all 4 tail surfaces together so you, in effect, have thrust vectoring and that puppy would do really crazy stuff. Use some really wide end plates as interplane struts, like 10 or 12 inches, and it'll knife edge until the cows come home.
Hmmmmmmm.............. Aw, I suppose I should finish my stock PBF first before I try something like this.........
BUT...... 4 inch separation on a 24 inch wing is not going to work worth a hoot. The air is just going to be way too confused in that small gap. In fact with the stagger you're looping over might just be due to the slot effect you've got going.
If you want to try a bipe what about increasing the gap to about 10 or so inches (12 would probably be better) and use a pylon'y thing to mount the engine right in the middle between the two wings. Couple all 4 tail surfaces together so you, in effect, have thrust vectoring and that puppy would do really crazy stuff. Use some really wide end plates as interplane struts, like 10 or 12 inches, and it'll knife edge until the cows come home.
Hmmmmmmm.............. Aw, I suppose I should finish my stock PBF first before I try something like this.........
