I want to use something like Sullivan Nyrod, or some other cable to pull the flaps down on my 80" Bates Hellcat. I plan to put one high torque servo in the center of the wing, and then run something out to the flaps (two on each side). It would be nice if they had little flex, and are not affected by changes in temperature. What do you use (part numbers would be nice)? Thanks.

Your going against excepted practice and may find it difficult to do. Having said that, Sullivan does make a carbon nyrod now that they claim does not shrink or expand due to heat. The fewer linkages you put in your plane, the happier you will be. Servos are cheap and very reliable.

I like the idea of keeping it simple, but a servo per flap would be four servo's total. I guess this would be ok if I used smaller and lighter servo's. What do you use for servo's for flaps? Is this the method commonly used for flaps on warbirds? The plans call for one large servo in the middle with steel rods and bellcranks going out to the flaps...I WON'T be doing that!

Here is my Holman 80'
I ran one servo to the large flap and a wire between the large and small flap
two servos
use at least hitek 645 those are large flaps
dont go cheap on servos $30 $1000+ airplane