O.S. Engine OSMG1975 91HZ High-Performance F3C Engine  [OSMG1975]

Competition-Focused Power with the O.S. Engine 91HZ

The O.S. Engine 91HZ is a competition-focused helicopter engine refined from the 91SZ-H platform, prioritising steady performance and practical serviceability. Its updates aim to simplify setup while maintaining power for demanding sequences.

Thermal Management for Consistent Output

A slim heat sink head gives flexibility for tight cowling fits and helps channel air through common shrouds. The dual heat sink approach on head and crankcase helps control operating temperatures so power stays predictable under load.

Stable Carburetion and In-Flight Tweaks

The supplied 61B carburetor improves mixture stability. An insulating ring stops crankcase heat from upsetting carburetor settings and multiple O-rings reduce the chance of air leaks. The in-flight needle adjustment arm lets pilots refine mixture without interrupting practice or competition runs.

Ideal for competitive flyers and advanced hobbyists, the 91HZ combines manageable installation dimensions with tunable controls to help maintain consistent performance in the field.