ORIGINAL: tripower222
ORIGINAL: Hossfly
The climb/descent of an airplane with a change in airspeed is simply an increase/decrease in the production of ''lift'' by the main wing in traditional convergent airflow. A lifting stab will not totally change that. It can help some but not adequately to rule out any change with aircraft velocity changes.
There is much more but not needed here.
The airfoil on the stab, if calculated properly it can become proportional, and lift the tail to change AOA compensating for for added wing lift at higher airspeeds. Thats fact and it is done on real aircraft.
The lift or negative lift is also there to compensate for center of lift changes (with airspeed) on swept back wings full size aircraft..
ORIGINAL: Hossfly
It does to a degree, However with any change in airspeed the lift of a lifting surface is increased by 1/2 of the square of the airspeed (airspeed being the actual flow of air molecules over the surface, known as Indicated Airspeed, NOT True Airspeed, Groundspeed, and/or Calibrated Airspeed) However the surfaces being different the change in lift-force produced with a change in airspeed is NOT directionally proportional.
Your formula has to be for a particular airfoil at a specific AOA. At 0 deg. AOA the lift on a symetrical airfoil wont change at all with air speed, and it will gain proportionally with increased AOA ultill stall.
Would you please explain just what provides the FORCE to move that symmetrical wing into an AOA to produce the lift force needed to move and/or sustain the Sym. non-lifting airfoil into the AOA to obtain a desired result? IMO it is the horizontal stabilizer, be it a conventional stabilizer/elevator function or a slab. Pilot adjusts elevator/slab which loads wing into position to obtain desired result.
The stab lift force is changed to move and/or maintain the wing into the desired position of the pilot's request via the control system.
An airfoiled stab, if symmetrical, acts just like a wing. Something has to move it into a position to become zero-loaded or it will continue to guide/load the wing into a constantly varying load position. An airfoiled stab, such as a Clark-Y will provide lift, just like a wing, by the square of the airspeed. Only by moving that stab into its zero lift position will the force be neutralized, and that neutral position will change with a change of airspeed.
In 1:1 scale, some light airplanes, a flat slab can bare the structural load (except some of the 3D Arfs which cannot. BTDT [:@] ) In larger airplanes a symmetrical airfoiled stab is more structurally effective, plus the form drag is considerably less.
Still, except for racing events and Scale fidelity to outline, I can see no reason to worry about the need to try to maintain the one-trim-fits-all subject in toy airplanes. It doesn't happen in 1:1 scale and it ain't gonna happen in RC.
BTW, the FF model. Very overpowered. Lifting stab provided help in keeping the aircraft from looping as the lift on the stab provided same as down-elevator, during climb portion. Far aft CG kept things proper during glide. I won a number of trophies in '60s and early '70s in FF.
The late Hal deBolt was a model designer of the first degree. In the '60s, early '70s, there was a pylon event for Formula 2 Pylon Racing. Hal used a flat stab, but set at a positive incidence. Of course the stab actually sets the true incidence line so aerodynamically the flat stab was the real zero. It did work fairly well in reducing the trim problem when one really was going fast.
Back in those days, a pylon Racer actually got to fly straight and level between the pylons. Never happens now so all is purely academic.
And to all: The Beginner seldom goes to the advanced Aerodynamics forum. IMO, they need to learn that there is more to aviation than banging sticks like a computer game. This kind of discussion at least provides an opportunity to become better informed.