OS Graupner Wankel Rotary Engine, 4.90cc Type 1

Today we run OS Graupner Wankel Rotary Engine, 4.90cc capacity, Type 1.

In summary: an easy starter, extremely responsive to the throttle, near zero vibration, enthusiastic exhaust note but not loud, emits an effective smoke screen (25% castor oil in the fuel mix) & sucks the fuel down like there's no tomorrow. Max RPM 14,534 rpm on an APC 9x6 prop & idled at about 4,600 rpm with that characteristic lumpy barking sound that Wankels make. I have seen higher RPM for the engine on other Youtube videos however those engines were run on higher nitro content & much thinner oil / lower ratios which will quickly wear out the rotor tip seals.

The engine came to me slightly used (eight flights I'm told) & appears to be in near excellent condition, apart from the hole drilled in the front of the muffler. Previous owner had the engine mounted as a pusher & concerned about the exhaust gases being inhibited by the forward flight of the aircraft - a simple silicon exhaust deflector would have done the job. Moan .....

OS Wankel engine reviews:

http://modelenginenews.org/drj/os_wan...

An earlier version:

http://sceptreflight.net/Model%20Engi...

• #sports
• #os_wankel_graupner_nsu_rotary_engine_rotor_nitro_methane_methanol_castor_oil