Designed primarily for the 3D flight and dramatic aerobatic
manouevres.. Compared to the old 'Hyper' the new 91HZ-PS offers improved
hovering stability as well as power at high speed to meet the further
sophisticated 3D competition manouevres.
A new design piston and crankshaft reduces vibration to provide
further, stable torque over the entire RPM range. The rectangular
heatsink head is completely included in the cooling shroud for better
cooling. The black alumite finish with O.S. and 91HZ-PS logo impart a
distinctive image.
A Thermo insulator is installed on the carburetor mounting spigot and
helps shut out engine heat to the carburettor, which in turn ensures a
stable fuel/air mixture
The 91HZ-PS is equipped with a new, bigger capacity PD-08 pump and
matched 61B-P carburettor plus integral regulator, which assures a
consistent fuel supply irrespective of violent changes in model
attitude.
Combined with O.S. pump system, internal parts improvements same as the
91HZ contribute to stable power output and smoother higher engine
performance.
Specification
Displacement: 0.91 cu in (15 cc)
Bore: 1.091 in (27.7 mm)
Stroke: 0.976 in (24.8 mm)
Output: 3.5 ps @ 15,000 rpm
Practical rpm range: 2,000–16,000
Weight w/o muffler: 22.39 oz (635 g)