Reynald's number
Good reasoning on span effects, pretty bad on flaps.
--------------- Also in playing with model flaps - I found that flaps do not increase lift - just change AOA.
If the flaps can actually increase usable area -then lift will increase -------------
Flaps are best evaluated in a wind tunnel. The problem is that deploying flaps also usually causes a big pitching moment and the airplane has to be retrimed to fly level. A simple test is using RealFlight. Some models pitch nose down with flaps and some pitch nose up. (not too scientific but an indicator).
In the wind tunnel looking at a Lift Coefficient vs angle of attack (CL vs alpha) the basic curve goes through the 0-0 axis intersection point. Increasing alpha causes the angle of attack to go up. Deploying flaps will offset the curve upward by the increase in lift of the flap. The pitching moment curve will show a big shift. If you look at the curves that I added to the end of the airfloiled stab discussion it will indicate a trend. A deployed flap will look like the +tail deflection on the CL vs alpha curve. Note though there are no nonlinear effects given. Too hard.
----------The wing that has has the best CL --may be a lousy setup for a model - ------------
Depends on what you want the model to do. Not a good general statement
------------------- EXAMPLE:
To get best CL- you need a wing with a fairly long span (relative to chord)
N/Y?
Let's go with Yes
IF- you attempt very tight -skidding turns with this wing -at low speeds -- the inboard panel will see less air flow than the outboard panel.
N/Y?
Again, assume Yes (turning radius , difference effect.)
A very low aspect ratio wing , tho really not as good for max CL number ,
will tolerate this tight turn much better
N/Y?
I say yes -
I tested this theory - by flying stuff ranging from the Klemm trainer design (old German design) to some goofy stuff with more chord than span. ---------------
Well look at the equations and save a lot of test flying :-) AC is the aero center of each panel.
The distance the ACs travel in a turn .........
Distance Inboard AC travels = RIac = 2 * Radiusin * pi
Distance Outboard AC travels = ROac = 2 * Radiusout * pi
Where Radiusin is the radius from the center of the circle to the inboard AC
and Radiusout is the radius from the center of the circle to the outboard AC
Velocity of ACs (rough approximation) in a turn .........
VInAC = RIac / circletime
VOutAC = ROac / circletime
The lift on the Wing ACs in a turn .......
LiftInAC = CLIn * 1/2 * rho * VInAC * VInAC
LiftOutAC = CLOut * 1/2 * rho * VOutAC * VOutAC
If CLOut = CLIn = CL then the difference in lift between the inboard and outboard wing is
LiftInAC = CL * 1/2 * rho * VInAC * VInAC
LiftOutAC = CL * 1/2 * rho * VOutAC * VOutAC
or another was of lookiing at it is
LiftInAC ~ VInAC * VInAC
LiftOutAC ~ VOutAC * VOutAC
DeltaLift = LiftOutAC - LiftInAC
DeltaLift = 1/2 * rho * CL * ( VOutAC * VOutAC * - VInAC * VInAC )
=( rho * CL / ( 2 * circletime * circletime ) ) *
( ROac * ROac - RIac * RIac )
or
DeltaLift ~ CL/ circletime * circletime * ( ROac * ROac - RIac * RIac )
So you have the differences in lift between the outboard and inboard panels proportional to the differences in squares of the distances from the center of the circle to the aero centers of the wings, proportional to the Lift coefficient of the wing and inversely proportional to the square of the time to make one circle.
What does it mean if I haven't goofed the math. The greater the span the greater the differences in the wing lift from side to side. The faster the turn the greater the differences. The greater the CL the greater the differences.
For the same airplane speed and radius level turn your low aspect ratio wing will show less response in roll (where the difference in CL will show up first) than a higher aspect ratio.