I used Pro Lynkx from Digitech Turbines: http://shop.digitech-turbines.com/pr...r9vc4vsdo1qr41

Drop in set that's good for grass operation, has possibly the best brakes I have come across, have a look, only problem is they cost more than the airframe, but then the airframe is very cheap and needs a lot of work to make it airworthy with a turbine.

Mike