ORIGINAL: Jet_Plane
rmh,
No doubt drag under certain circumstances can change the way a plane flies, spoilers, air brakes, drag rudders, etc are all example, as are the drag producing 'fences/spoilers' you see on indoor models. However the drag produced by slight elevator defection is a very small force and as the elevator is usually near the centre line of the plane that tiny drag has no significant effect on the pitch of the plane. Consider the fact that for a typical airfoil lift force is about 50 times greater than drag then you start to appreciate that drag plays a much smaller part than lift in the forces generated by an unstalled airfoil.
I know you have in the past expressed the theory that the tail of a plane controls mainly by drag but you are alone on this one and would need to come up with some pretty solid evidence to convince most people.
in any case i dont think this is relevant to the OP's problem because he didn't say that one model had more elevator deflection than the other.
Steve
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Perhaps you have have a better answer -
The elevator is often not near the center of the center line (Ttail is an extreme example)
My noting that drag can be used as a control device is easy to prove using split control surfaces.
I have done it, as I am certain, have others.
On speed designs -it is easy to reduce the tailplane size -thinking that only small pitch changes are required
If you plot drag from front to rear on the design - the drag becomes smallest at the tail.
small changes here are important
On a racing car (straight line speed) - IF you run slightly lower air pressure in one rear tire - the car will pull to that side
In this case- difference in rolling resistance and or traction.
I am not trying to convince others - I really have no interest in that .
I simply relate what I have tried and observed.
As for the elevator deflection being the same with a difference in incidence and no change in CG?
That simply won't happen.