O.S. Engine OSMG1977 91HZ-PS 3D Ring Helicopter Motor  [OSMG1977]

What the O.S. Engine 91HZ-PS Brings to 3D Flight

The O.S. Engine 91HZ-PS 3D Ring is engineered to deliver stable throttle feel and reliable power delivery during demanding 3D routines. Its layout supports predictable performance when pushing aggressive flight envelopes.

Accurate Fuel Delivery Under Load

The updated horizontal regulator teamed with the PD-08 pump maintains a constant fuel feed in steep and inverted attitudes. This keeps engine behaviour steady so pilots can focus on control inputs without fuel surge issues.

Smooth Powerband and Lower Vibration

Careful attention to piston and crank geometry reduces vibration while retaining torque throughout the rpm range. That smoother operation helps with precise cyclic and collective control.

Tight Profile Cooling and Carburettor Heat Management

A narrow heat sink head makes it easier to package the engine inside close fitting cooling shrouds while still shedding heat effectively. The 61B-PII carburettor uses a thermal insulator to limit heat soak and keep the fuel air mix consistent.

The O.S. Engine 91HZ-PS 3D Ring is a practical choice for tuned 3D airframes where steady fuel flow and controlled vibration matter. It fits into competitive setups that require repeatable engine response.