O.S. .91 HZ-R 3D Speed Competition 3D Helicopter Engine w/61G Carburetor

91HZ-R 3D Speed Features:

• Designed for all-out, aggressive 3D competition.
• Offers incredibly stable mid-range torque for awesome 3D flight
• Carburetor inlet enlarged to 11.2 mm
• Exhaust port timing set at 165°
• Combustion chamber shaped to match the big bore carburetor and advanced exhaust cylinder timing
• Demand Regulator System (DRS) guarantees a steady fuel supply to the carb at any attitude, on a full or empty tank and during the most abrupt throttle changes
• Lightweight, machined cooling head
• Crankshaft counter weight has been modified to reduce vibration at high RPM
• Black anodized crankcase offers better heat dissipation