I'm working on electrifying an Ultra Sport 60. And I want to make sure I get the power system correct.

I looked at the plans last night and they specified 3 glow engine/prop combinations.

1. (4-stroke) OS MAX FS-91 with 11x11 prop
2. (4-stroke) OS MAX FS-70 with 11x9 prop
3. (2-stroke) OS MAX .61 SF with 11x8 prop


I *think* I've come up with some combinations that will work.

I guess my first question is....

What RPM can I expect these motors to spin these props? At half throttle? At wide open?

The reason I ask this comes from one overruling requirement. I am using stock landing gear, so I have the same prop clearance as I would if I were flying glow.

So, to my reasoning... If I have to spin the same diameter props, I must spin them at the same speeds to get the same performance.

My goal is to have an electric plane the flies the same as a stock built/powered glow version.

I'm not interesting in uber performance setups (tuned pipes, larger motors, etc.)

I hope that makes sense...

I hope someone out there has these motor/props and has some measurements with a tach....

Thanks in advance...