Can anyone suggest a prop size for this engine? I lost the manual and looked online and couldn't find anything. I run 11x5 or 10x6 on my other .46's, would that be ok for this engine? I have a tach also but I don't know what an acceptable WOT rpm is with this engine. Any help is appreciated. This engine is on a small Cap 232 if that changes anything. Thanks.

11-5 would be a good starting point. This should give you approx 60mph in a clean airframe. Acceptable RPM will be around 300 RPM below max.

11x5 is an excellent starting point. you might even try a 12x4.5 i think apc makes them. i like to prop for thrust rathar than speed on aerobatic planes. an authoritative climb out is what you want!

-matt

Thanks guys. I'll give that a try.

Just prop it like a 46FX, the SF is a great engine!

I would try an 11x5 for sport or 12x4 for 3D, all the way down to a 9x8 on a speedy ship--

Enjoy!

First questions are always what are you going to put it in and what kind of flying do you want to do? You've answered the first.

A solid enough & reliable engine, the SF isn't as powerful as the current generation of leading sport .46 engines. A 10x7 APC would be a good choice for it in that CAP, though she'll slip along quite quickly. Alternatively, an 11x5 as others have suggested will also work well.

Either will sustain sufficiently through manoeuvres, though a different technique is required of each. The 10x7 will fly the CAP faster, but requires superior energy management in converting speed to height (vertical). The 11x5 requires less finesse, making better use of that engine's torque to haul the airframe around under sustained load. Buy one of each, try them and decide which best suits your preferred flying style.

I like APC 11-5 props on 46 size engines. Gives enough speed and pulls hard wehen you need it! [8D]

Thanks everyone. I'll start with the 11x5 and see how that does and adjust accordingly.