rainedave

My Feedback: (1)

I've been wanting to design a 1/2A bipe for a TD or AME .061 for a while. I haven't gotten too far yet. I basically took the SS taper wing and scaled it down. One version I swept back and I thought this could be the top wing. Or, both wings could be straight or swept. I want to use the same moments and tail areas of the SS because I really enjoy flying them as they are. I've arrived at a span of about 21 1/4" which seems about right. The root chord is 4.375" and the tips have a 3" chord. That gives a total area of 158 Sq." for both wings, which, again, seems about right. I'm open to suggestions since I've never designed a bipe before.

David

Mr67Stang

Funny you should bring this up. I was concidering ordering another SS kit from you with an extra wing kit for this very purpose. Thinking I wouls Clip the wings such that the lower wing would be 2 inches shorter span than the top wing something like 24in top and 22 in bottom. But what do I know

combatpigg

My Feedback: (3)

RD, since bipes this size won't have much more than 10 inches of unsupported span anywhere, the wings can be built lighter. Thin the wings down somewhat. 4 ailerons is the only way to go. To keep the combined MAC [of the 2 wings] at the same point as your monoplane, the lower wing will need to move back a little. Increase the tail feather area, give it a manly rudder. My Goldberg bipe has most everything set at 0-0-0, except the O.S. 1.20 needs right thrust, a 1/2A engine swinging a 6x3 won't. Sounds like a great way to start your building season!

Remby

My Feedback: (3)

Yep, Bipes are cool. Bipe Flyer should be able to add a bit of input, havent see him post in a while.

Had a All Star, and it was 34(?)" span, straight cord wings. That had a .15 on her, I would think around 26-27" span would fly well on a .049.

Keep us posted..

rainedave

My Feedback: (1)

Thanks everyone. Yep, cp, I goofed on the wing airfoils; I scaled the ribs, but not the sheeting thickness which made the wings thicker than I wanted. They were originally 11% at the root and 13% at the tips. I'll need to thin the rib patterns a bit more. May be I should even go down to 9% transitioning to 11% since I'll have two wings. I'm sure there's some formula, but, would two 9% wings approximate one 18% thick wing in terms of drag? It's probably not that simple.

The SS's tail is over-sized as it is, which is probably why Joe's does such quick snaps.

The next thing to do is study up on the best distance between the wings and amount of stagger. I was also thinking of going 0-0-0-0.

Thanks, more to come.

David

flyinrog

My Feedback: (1)

Raindaive, as usual I have more kits than time,,, I have a simple series ultimate bipe if your interested in building one,,,I also have plans for the 1/2a bipe that Bipe drew up it you'd like a set I can get a copy made....Rog

combatpigg

My Feedback: (3)

RD, consider your vertical CG and keep the thrust line centered between the wings, also. I disregarded this during a scratch build and came away with a bipe that flys great right-side-up and is impossible to fly inverted.......it snaps out of every attempt to fly upside-down. For stagger and spacing, just look at some popular designs, I think rule of thumb is the law with nothing etched in stone.

OzMo

My Feedback: (3)

A center pylon for the top wing, like a Parakeet, would allow the deck construction to remain basically unchanged. It could have a fin shape.