O.S. Max .91 HZ-R 3D Competition Helicopter Engine w/Regulator
This is the O.S. Max .91 HZ-R 3D Competition Helicopter Engine. Based on the multi-time FAI world champion 91HZ helicopter engine, O.S. is taking the 91HZ-R to even higher levels of performance, thanks to the new "on demand" regulator system!
Designed specifically for this engine, this system guarantees the steady fuel supply, needed for the most-demanding of 3D flights with constant, vigorous attitude and throttle changes.
The 91HZ-R also performs well as an F3C powerhouse providing a steady, smooth run and exacting mixture controls.

Unlike the pressure created by a pump or muffler, the regulator ensures that the fuel arrives at the regulator under a constant pressure.
 This means the engine will run exactly the same throughout the entire tank- from full to empty. Additionally, this regulator has been designed so that the mounting position of the system is perfectly in line with the carburetor resulting in consistent engine operation in all attitudes of the model.
Rest assured, 91HZ-R will never be lacking in fuel or lagging in performance!

Specifications:
Displacement: 14.95 cc (0.912 ci)
Bore: 1.091 in (27.7 mm)
Stroke: 0.976 in (24.8 mm)
Practical rpm: 2,000-16,000
Power Output: 3.4 hp @ 15,000 rpm
Weight: 22.05 oz (625 g)

Includes:

    * 61ER Carburetor
    * #8 Glow Plug
    * Check Valve
    * 0.2mm Head Shim (Engine has a 0.1mm head shim installed)
    * (2) 2.6X5 Needle Adjusting Screws