Guys,

Hope someone can help me!?

I have a Miss Wind 50 with a Hacker A50-16S and Hacker X70SB ESC which has developed a problem.

If I advance the throttle slowly, the motor starts with a really harsh almost bang like noise but then spins freely and quietly. Advancing the throttle has the motor running nice and quietly and smoothly until about half power when it starts to harden and get louder. Advancing to full throttle, the motor sounds like a petrol engine and is down on power. It also empties my lipo pack in about 2mins instead of 8mins [X(]

Nothing is loose, prop is balanced. It just started happening a couple of flights ago.

Any ideas?!??! If I remove the motor and turn it by hand it feels fine.

Thanks,
Mark