Hello, I want to try a YS .91ST for a speed prop plana. What is the RPM range of this engine? Is it easy to conevrt to prop?
Thanks
Ed

Ed, I'm not sure that engine could be converted to propellor use as it does not have a drive washer and to the best of my knowledge YS did not make a 91 two stroke for airplane use like they did in the 60 and 61 size. It would be interesting to see a 91 two stroke YS on an airplane.

I already sent him an email, but it uses the same collet and drive washer as the 60 (61?) airplane motor.

very good to know. Have you flown this in a plane? What was the performance?

Hi Yak13,

Here are the spare parts list for converting YS91-SR to prop;

Drive Washer Retainer - F9324
Drive Washer - F9323
Tru Turn Prop Nut - TT-0813-A



I converted this engine some time ago, did not take any RPM readings, used this engine with pipe in a 1.77 metre aerobatic model and all I can say is take some bike clips with you!!
Hope this helps.

Sydc