ORIGINAL: selnekav
in other words is there any diffrence of P-Facor affect between normal and inverted flight ? if P-Factor force is linear to the prop rpm then i whould think using rudder to throttle mix will be much more affective then a constant right thrust angle that will be affective only at high rpm am i missing here something ?
P-Factor is a mini effect.
The main effect is caused by the spiralling air stream. ....not at idle throttle though. For the spiralling air stream to be a major problem the model must be in acceleration mode or at least trying to accelerate while another factor (gravity) is keeping it from accelerating. That's why models veer to the left when they are accelerating on ground or when climbing vertically up or turning a corner. When speed is reached, the effect is lessened.
At idle, the spiral stream is much smaller hence the effect is less. One of the main reasons pattern models should always be accelerated slowly
Air moved when the prop is at full rpms has a surprising amount of mass. It's this mass of air that causes the various unwanted effects. Dean Pappas and I have been discussing this phenomenon off and on for a couple years now. Dean wrote a good summary in the latest Model Aviation issue.
Rudder to throttle mix may be effective for some fliers but isn't for everyone....the effect is nonlinear and dependent on model speed. But is easy to do.
Engine offset is still a better solution for many fliers because the result is more linear, dependent on engine thrust rather than model speed. The best solution is to design a model that needs no offsets at all, but that's beyond this discussion. Jet jockeys are laughing!!!
MattK