Biplane wings
 

:DIs the incidence suppose to be the same on the top and bottom wings,it wants to climb

RE: Biplane wings
 

Most of the bipe designs I've seen have the lower wing incidence set higher than the upper so it stalls first.

RE: Biplane wings
 

With my Goldberg Ultimate Bipe the incidence on each wing is 0, I do not know if that is common or not, but that's what it had me set the incidences to.

RE: Biplane wings
 

On both my Acrostar and SE5A the lower wing is set at 0 and the upper is at positive, 3 degrees and 2 degrees respectively. both planes perform well with no climbing tendancies.
Bill

RE: Biplane wings
 

On seven Aeromasters, two 40 sized Phaetons and two Lazy Aces, all required that the upper wing be about 1.5 degrees less incidence than the lower wing in order to fly nicely. Just a minor change made all the difference in the world on how well they flew.

RE: Biplane wings
 

:DThanks for the help guys.Maybe I can get this thing flying

RE: Biplane wings
 

Tree, the climb tendency is not only related to your wing incidence but also to the tail incidence and CG position. You need to first ensure that the wing and stab angles are "in the ballpark" for the type of design and intended style of flight and then work the CG to set the trim as it should be. Overpowering a model with angles that was intended for moderate flying is a good way to have one that wants to climb under full power.

What model design is it and what are some of the specs?

RE: Biplane wings
 

It's a Thunder Tiger 40 i purchased from a friend CG 1/4'' back of main spur top wing It has 36 mag It has no specs. for incidence ,but the top wing has 3deg pos. bottom has 2deg.neg stablizer 0deg.

RE: Biplane wings
 

I set all my fully aerobatic bipe's wing incidence at 0-0, or sometimes about 1/2 degree negative on the upper wing, with zero on the lower wing. Wind tunnel tests conducted in the 1930s by NACA showed that induced drag was minimized by using about one degree or so more positive incidence in the upper wing, although the improvement was barely measureable.

RE: Biplane wings
 

Tree, I suspect there may be a wing rigging setup error with that model. Provided you measured it right a 5 degree difference between the top and bottom is a LOT!

Is [link=http://www.chiefaircraft.com/cgi-bin/rcm/hazel.cgi?action=serve&item=/Models/PowerAirplanes/ThunderTiger/TTTigerBipe40.html]THIS THE MODEL?[/link]

RE: Biplane wings
 

Yes this is the model arf.

RE: Biplane wings
 

On some biplanes were the top wing is farther forward than the bottem wing the top wing should be at a positive angle. If the top wing stalls first the bottom wing still flying will cause the plane to be nose heavy and the plane will be controlable. I have used the sim X-plane to test many bi-plane configurations. All of my 1/2 scale planes have been tested in X-plane. And all have flown great.

RE: Biplane wings
 

tree,
if all the wing incidence suggestions fail to help, try adding 1-2 degrees downthrust. this may help alot, especially if your model tends to climb when power is applied.
/chazM