This is a high-performance engine expressly designed for 50 size helicopters. Since engine mounting and muffler mounting bolt patterns are the same as the 50SX-H Hyper, it can be installed in the existing 50 size helicopters. The newly designed 40L carburettor enables independently adjusting idling, hovering and high speed. Close to 60-size power offers a wide power range suitable for sport and 3D flight.