this might seem like a stupid question but is it possible to build a bi-flying wing, and has it being done before. i dont know a great deal about aerodynamics but get the feeling something like this would just tumble in the air

Do you mean two wings set up like a byplane ,but like a flying wing? If so , I don't see why not if set up right.

It has been done in a full-scale aircraft: see http://www.ctie.monash.edu.au/hargrave/dunne.html

There is an Aeromodeller plan for a Dunne wing fee flight model.

thats the kind of thing i meant, like a bipe with no tail maybe a bit more modern. would it work as a slope soar or would the top of one wing and the bottom of the other be in dirty air. can anyone think of any advantages or disadvantages to this setup

was thinking maybe 2X zagi style fixed together

That would be a drag farm. It will work, but poorly.

It would definetly work best as a powered model. Any biplane format generates more drag for the area than the same area monoplane.

I don't know about electrics, but there are glow powered flying wing bipes. Here are a couple by Claude Vest in Indiana. All he flies are flying wings.

Here's a link to a photo of the Easy Riser biplane hang glider/ultralight that was popular in the late 70's. It was designed by Larry Mauro and the kits were sold through his company, UFM. I built one while in college and flew it a few times as a Hang Glider. After a nasty crash while "ground skimming" it I sold it and bought a more conventional rogallo wing glider that I flew for many years.

Jim



[link]http://www.delta-club-82.com/bible/photo.php?id_aile=701&langue=en[/link]

There was a bridge engineer glider pilot, whose name I can't remember, who figured out how to brace the wings of a biplane against eachother. Otto (o#o) Lilienthal apparently didn't get the news in time to save his life. Since then, biplanes have been much lighter than similar monoplanes. For models, though, the lower Reynolds number is a big disadvantage, and the drag of the wires and struts is always a big disadvantage at high speed.
Since Germany didn't finish any aircraft carriers and even biplanes are a lot faster than torpedo boats, the Ferry Swordfish had a fine record in WWII, being better at flight deck landings and takeoffs than a monoplane.