I've put together a model plane in the form of an angel, and the planform is quite tail heavy (please see pic). I'm trying to balance the plane with a lifting tail prop that makes the "apparent" CG in the place where the CG should be. I've launched the plane twice. The first time it seemed like there wasn't enough forward thrust. The second time the tail rotor didn't have enough thrust and it pitched upwards. (Please see video links). Will this concept work if tweaked properly?
Tryin' to cheat the laws of stability, aren't we?
In both videos it is evident that the plane is unstable in pitch. Adding a lifting prop will not change this, because changes in the angle of attack will not affect this prop's lift force much. Stability is achieved by shifting the center of gravity forward, so that changes in the angle of attack will produce additional forces which create a counteracting pitch moment.
In fact, adding the motor will shift the center of gravity even further back. In some cases this helped because the increased pitch inertia made it easier for the pilot to keep the aircraft under control.
If you need to keep the center of gravity so far backward, add artificial stability with a pitch rate sensor and a microcontroller which deflects the elevator appropriately. There are many pages with Arduino-controlled artificial stability solutions - take your pick!
Maybe. Pitch stability could be the biggest problem. The "tail rotor" will have to vary its thrust according to airspeed in order to match what the wing is doing. Let's say the aircraft is in straight and level flight, with the tail rotor delivering an appropriate amount of thrust. Now if the airspeed increases only slightly, the wings will generate slightly more lift, but because of their position, will create a significant nose-up moment, so the aircraft will pitch up rather abruptly. Of course, only a slight increase in tail rotor thrust will offset it and keep the aircraft in balance. You might want to ditch the traditional tail surface altogether and control the tail rotor via a feedback control system cued by angle of attack. Your flight control input would then adjust the target angle.