I forgot to mention one important point about incidence. I am referring to everything on "zero" with a fully symmetrical airfoil. Symmetrical airfoils require angle of attack to generate varying degrees of lift while semi-symmetrical airfoils require incidence to counteract lift while the model flies in SLF.
A trainer model is a perfect example of this. With a flat bottom wing the plane can only be trimmed for SLF at a particular throttle setting. Adding or decreasing power past that point and your throttle, in essence, becomes an elevator. I'm sure you all understand this but I am just using it as an extreme example. I don't know of any biplane that use flat bottom wings except maybe the old "Big John" or "Lazy Ace" style bipes and they are in no comparison to a F3A bipe but while studying "aerodynamics 101" the rules of flight are consistent, only the parameters of the airframe are different.
The perfect airframe setup for "0-0-0" is a plane that the wing and stab are on the exact same centerline as the engine. Any deviation from this platform will result in the need to tweak the flying surfaces. A nice straight arrow will fly perfectly straight but put a Z- bend in one and see what happens. Same goes for an airplane. Once you start moving things away from the centerline of flight things change dramatically.
Look at todays modern single wing aerobatic aircraft. They are the epitome of advanced aerobatic design BUT who can pass up the appeal of a biplane. I know I can't!
Please keep in mind that the comments I am making refer to aerobatics only.
Scale models , along with other types of specialized flight, is a whole different ball game.
I hope you guys don't think I am getting too far off topic considering the OP was directed at F3A biplanes but the OP said
any input was welcome. I'm going back down to my building board now. This is an interesting forum and hopefully it will
not end up in another hair balled argument like so many others.
Last edited by Speedy-Gonzales; 03-09-2014 at 11:38 AM.