O.S. Speed Tuned 91HZ-Rs

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O.S.^® Speed Tuned 91HZ-Rs

Features

91HZ-R 3C Speed: A carburetor intake bore maximized to 11.2 mm and cylinder exhaust timing advanced to 170° combine to produce extreme horsepower for faster flight speeds and more stable hovering.

91HZ-R 3D Speed: With the carburetor inlet enlarged to 11.2 mm and exhaust port timing set at 160°, the 91HZ-R 3D offers incredibly stable mid-torque power for awesome 3D flight.

O.S. Speed Tuned 91HZ-R 3C Speed w/PowerBoost Pipe

91HZ-R 3D Speed w/PowerBoost Pipe: All the features of the 91HZ-R 3D, plus a PowerBoost pipe for precision performance from high RPM maneuvering to idling and hovering.

The first speed-tuned aircraft engines from O.S.

O.S. introduces the Speed Tuned 91HZ-R 3C and 91HZ-R 3D, exceptional heli engines for F3C and 3D competition. Both share many great features, not the least of which is the “On Demand” Regulator System, which delivers fuel consistently to the carb regardless of the heli’s attitude or the pilot’s flying style!

Featuring designed combustion chambers, shaped to match the big bore carburetors and advanced exhaust cylinder timing.

Lightweight, machined heatsink heads.

Crankshaft counter weight has been modified to reduce vibration at high rpm.

Anodized crankcases offer better heat dissipation.

“On Demand” Regulator System guarantees a steady fuel supply to the carb at any attitude, on a full or empty tank and during the most abrupt throttle changes.

Specifications

Displacement: 0.91 inł (14.9 cc)
Output: 3.6 hp @ 15,500 RPM
RPM Range: 2,000-16,500
Weight (w/o Muffler): 21.2 oz (603 g)

Requirements: 10-30% nitromethane fuel with 18% (min.) lubricant content. Lubricants may be either castor, synthetic or castor/synthetic blend, Field equipment, Muffler (depending on heli)