Another one -
I've read lots on this thread about whether to use a single aileron servo or a pair. In addition, I've read lots on using a single or a pair of mini servos for flaps.
I've used the single aileron servo setup on the P-47 which I've been flying for about 18 months or so. I'd respectfully suggest that provided it's all assembled correctly there is no reason for it to fail in flight. The only slop will arise from the bellcranks if they are not installed properly and they are able to move in more than one plane. Providing they are secure on their mounting plates they transmit the loads perfectly well. As the pushrods are guided through the ribs of the wing, the potential for buckling is minimal.
As for loads on the aileron servo I think it has to be remembered that these are scale models, not aerobatic or pattern models. The ailerons are small compared to the wing area for a model and a single servo has no trouble moving them. If any pilot is aggressive enough with the ailerons for servo power to become an issue, then the overall heavy-handed flying style will destroy the model sooner or later anyway. Fly it smoothly and scale-like, and you'll find one servo more than up to the job.
Conversely, the flaps are large control surfaces which are intended to move a long way. In addition, the are intended to remain in position for long periods of time (ie lower flaps at low cruising speed and keep them there through the approach, landing and roll out. The flaps require a lot of muscle to hold them down at approach speed, never mind on go-around at full throttle, so the flaps need good quality metal geared standard size servos. A single high-torque servo in the centre section could work, but I'd expect mini servos to struggle holding the flaps for long durations. I can just hear that 'wrong' buzzing noise servos make when they're about to cry
