Hand proping the 3 cylinder radial is not difficult, it is a bit strange until you get used to it because one blade will be in a natural position, (depending where prop is mounted to hub, clock position), next blade will be low and third blade will be high, then back to natural position. If it is out of comfort range adjust prop in hub, clock position. It is not hard to prop but if it is not at idle make sure it is very firmly tied down and tied in such manner as tail cannot raise up when it starts. The torque this engine has if started above low idle is unreal and it can eat you up. If hand proping and it is difficult to start, requiring advancing throttle, make sure you check to voltage going to system.