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O.S. Engines


O.S. 55HZ-R DRS Ringed .55 Helicopter Engine

O.S. 55HZ-R DRS Ringed .55 Helicopter Engine

Regular price $516.79 CAD
Regular price $645.99 CAD Sale price $516.79 CAD
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This is the O.S. .55 HZ-R DRS Ringed Competition Helicopter Engine. The maneuvers in F3C competitions increase the level of performance these days not speak of 3D flight. This means the pilots demand more performance on its power source: engines. O.S. Engines has responded to the market demand on the cutting edge, which is always changing. The DRS (Demand Regulator System) is the ideal fuel supply system, which uses the primary pressure and improves your flight performance.

The DRS is developed for supplying ideal air-fuel mixture as pilots desire. A fuel tank is pressurized by the pressure from the nipple in the back plate via one-way valve so that the fuel is pumped to the regulator. The regulator picks up the negative pressure created in the venturi and supplies fuel consistently by controlling check valve according to carburetor opening. The carburetor is equipped with two needles to adjust middle and high speed precisely. The cover plate has a mounting hole to set a sensor of Futaba GY-701 governor, which secures more stable flight.


  • DRS system delivers fuel to the regulator under constant pressure for precise fuel delivery throughout the entire tank from full to empty
  • Mounting position of DRS is perfectly in line with the carb for consistent operation in all attitudes of flight
  • Same mounting bolt pattern as the OS 50SX-H Hyper
  • Dual needle 40L-R carburetor allows independent adjustment of idling, hovering and high speed with four arm throttle lever for use with a variety of servo brands
  • HZ Hyper low profile six fin cylinder head

Displacement: 0.55 cu in (8.93 cc)
Bore: 0.91 in (23 mm)
Stroke: 0.85 in (23.5 mm)
Practical rpm: 2,000-20,000
Weight: 15.1 oz (429 g)