German two-stroke aircraft engine
The Hirth F-33 is a single cylinder, two stroke, carburetted aircraft engine designed for use on ultralight aircraft, including powered paragliders and ultralight trikes. the engine is noted for its extremely light base weight of . It is manufactured by Hirth of Germany.
Development.
The F-33 was intended to fill the niche previously occupied by the now out-of-production Rotax 277. The F-33 uses free air cooling, dual capacitor discharge ignition and reed valve induction, with a single Bing 34mm slide or optional diaphragm type carburetor. The cylinder walls are electrochemically coated with Nikasil. Standard starting is recoil start. A belt reduction drive system, fuel injection, tuned exhaust and electric start are optional.
The engine runs on a 50:1 pre-mix of unleaded 93 octane auto fuel and oil. Recommended time between overhauls is 1000 hours.
The F-33 produces at 5200 rpm and at 6500 rpm.
Specifications (F-33).
"Data from" Recreational Power Engineering
General characteristics
Components
Performance
References.
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