I should receive my Spot On 50 tommorow. I already received my new YS FZ63s to power this plane. I hope this will be a potent combination for my first pattern plane. I will post pictures and answer questions to the best of my ability. Any help or suggestions are always welcome.

I would like some suggestions on the correct prop for this motor. I plan to use a 3-Blade prop, probably a 13-6 or similar.

Ive recently built a WM Spot On 50 -

Ive used a Saito 100 as power plant turning an APC 14x8 prop.

This combination moved the plane quiet nicely on uplines without losing momentum. And also provided nice prop braking on downlines.

Also I needed about 50gr of lead to the tail to balance the plane.

With YS63 you may even able to move the tank to near CG without affecting CG.

YS63 being nearly as powerful as a 91Surpass on smaller props, using APC 13x7 or 13x8 would pull the airframe nicely.

Bear in mind a 12 inch prop would struggle to pull the airframe on uplines IMO. (but could be used for basic sportsman class)

One more thing; you can stick a suitable long tristock to be used as air brake at the end of rudder for further downline braking.