Hi Greg,

I bought a Scorpion HK-4035-400KV 8mm shaft for use in my Curare and on 10S it'll swing an 11x9APC at about 13K static and in the air performs about the same as my old ASP.75 swinging an 11x10APC. For personal reasons I didn't want to go over 12" prop diameter as I don't intend to fly turnaround or 3D with it and with a 10S 4Ah pack the final weight came out about .5kg heavier than a full 16oz tank of fuel, so somwhere in the 8.75lb range.

This was a glow to electic conversion so it's heavy, if I were building one from scratch for electric, there's lots of places to save a bit of weight to to get it back to the 7.5lb range.

I too was looking to replace the Hanno in the Slingshot and hoped this motor would do the business on 8S with a 12"-13" diameter prop but to be honest I'm very disappointed with it from a quality perspective. The sharp edges around the case where the wires come out are chaffing points, it would't be so bad if the wires came out the middle of the hole but when they installed the stator, it's on a bit crooked so the wires are hard up against one side.

I only ran it for about 4 minutes in the Curare because the vibration was shaking the plane to pieces. Right from the first bech test there were bad resonances at certain RPM (bolted to a piece of 16mm thick laminated MDF and secured in a bench vise), which surprise surprise didn't get any better in the plane. A friend bought a similiar but different version of the motor and there were similar vibration issues. When it was running you could see the motor can bending and flexing. I sent mine back for "warranty", received it back and haven't even bothered to run it. It really needs a longer shaft so it can be supported by external bearings at each end. I ran mine front mount with no rear support, his was a back mount one with a bolt on prop adapter and it wasn't any better. I'll get around to machining up a longer shaft so I ca run a rear bearing in the old firewall to support the rear of the motor.

Apart from spinning the prop at the right RPM, and honouring their warranty I can't say anthing good about Scorpion motors, even the hole in the prop adapter is/was too big for the 8mm shaft making it unusable. They're probably really good in a chopper where the only load is a pinion and they can run at some non-resonance RPM. My Scorpion (and my friends) certainly didn't like a gyroscope hanging off one end and certain rpm....

But like anything YMMV...