Originally Posted by
Falkwulf
Hello all I have a few questions for this group both are about props, I have a FA-91 going on the front of a Ultra Sport 60 what prop do I need to run for it the book says a 11x11 for the .91 4 stroke but isnt that too small for th3 .91 and if so what prop should I run, also I have a RCFW F6F-5 Hellcat and am planning on running a Saito 125 on it but what three blade prop will i need to spin I was looking at a 16x10 or the 16x8. and last one of the squadron mates is building a TF GE P-51 what is the biggest 4 blade prop can he spin on the 125.
According to this
STATIC THRUST CALCULATOR, that (APC?) prop would be turning 11,000 RPM static @ 1.5HP. You would already be @ redline on the ground. The engine will over rev once the prop unloads when airspeed increases.
A 12 X 11 will bring RPM down to about 9800 on the ground & still generate almost 6# of thrust.
I recently converted an FA125 to CDI & on GI (hlow ignition) it would not sustain WOT W/a 16 X 8 prop. It would get too hot & backfire, spitting the prop loose. W/GI 15 X 8 or 14 X 10 is about max.