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O.S. Engines

Speed Tuned 91HZ-Rs

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

O.S. Speed Tuned 91HZ-Rs

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.

Displacement: 0.91 in3 (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)

91HZ-R 3C Speed Red
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Add To Wish List Tech Notes Accessories Needed
91HZ-R 3D Speed Black w/Powerboost Pipe
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Add To Wish List Tech Notes Accessories Needed

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