3D and F3C Helicopter Pilots—Get Ready for Power and Speed

Following the popularity of the 91HZ-R with On-Demand Regulator, O.S. has now taken high-performance, high-speed helicopter engines to the next stage of evolution. Introducing the 91HZ-R Speed Engines—based on the 91HZ-R, factory-tuned at the O.S./Japan facilities and guaranteed to blow you away!

The 3C version is designed expressly for F3C competition with its controlled, precise maneuvers in mind. For pilots who prefer aggressive, stick-bashing 3D flight competition, O.S. offers a 3D version.

Features found in both versions include:

  • Lightweight, machined heatsink head
  • Big-bore carburetors best suited for the intended use (F3C or 3D)
  • Best precision advanced exhaust cylinder timing (for F3C or 3D)
  • Newly designed combustion chambers, shaped to match the big bore carburetors and advanced exhaust cylinder timing
  • Lightweight, forged steel crankshaft counterweight to lower vibration for higher speeds
  • Improved back plate shape, to accommodate Futaba’s BPS-1 RPM Sensor and increase primary pressure for greater stability.

OSMG1980 91HZ-R 3C Speed Engine (red):
Achieve faster flight speeds and improved hovering stability. In order to get the greatest power from this engine, the carburetor intake bore is maximized to 11.6 mm. To match the large bore intake, the cylinder exhaust timing has been advanced to 170 degrees. This all contributes to extreme horsepower with high speeds for stable hovering.

OSMG1981 91HZ-R 3D Speed Engine (black):
Pilots who slam the sticks will be very impressed with the 3D version. This engine develops all the high performance required for stable horsepower at any attitude. The big bore carburetor is specially designed to develop stable horsepower at 70~80% throttle which is widely used in 3D flight. The matched cylinder exhaust timing has been advanced to 165 degrees.

OSMG1982 91HZ-R 3D Speed Engine (black) with PowerBoost Pipe:
For pilots eager to get every advantage, you have the option of the 3D version with the included PowerBoost pipe from O.S.—designed specifically for the 91HZ-R Speed 3D version.

#OSMG1980 91HZ-R 3C Speed (red) Street: $499.99
#OSMG1981 91HZ-R 3D Speed (black) Street: $499.99
#OSMG1982 91HZ-R 3D Speed (blk) w/Pipe Street: $699.99
#OSMG2881 PowerBoost Pipe 91 Street: $219.99

Vendor Information
Great Planes
P.O. Box 9021
Champaign, IL 61821
Phone: 800-637-7660

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