As new flat Boxer engines the 1100 RS/ GS/ have been introduced years ago into the quantity production. It is now time to let this technological top performance of the engine building fly.

As a result of our experiences with The Boxer-engines as aircraft engines since 1988, according to the state of the art we realized our ideas about a modern, high-performance propeller drive.

For ultralight planes this drive has been certified since 4/98. It runs with very few vibration, is quiet, extremely economical and strong.

The Highlights: Enormous power weight (to 0,77 kg/hp)

Extremely economical consumption (225 g/kW/h)

Processorcontrolled injection

Non-polluting due to regulated 3-way catalytic converter

Height compensation by crusher gage sensor

Continuous duty depending on motor 43 - 74 kW (70 - 100 hp)






R 1,1 RS

1085 ccm


66 kW/90PS/7200 min-1

R1,15 RS

1130 ccm


70 kW/95PS/7250 min-1

R 1,1 S

1085 ccm


72 kW/99PS/7500 min-1





Consumption: 7 - 10l unleaded at 75 %

Cooling system: 65% oil - 35 % air

Four-valve-technology: separate oil cooling (50 l/h)

for the outlet valve

Ignition system: Motronic (characteristic control) with emergency running control in case of breakdown of sensors

Ignition release mechanism: 2 independent Hall generators controlled by the crankshaft

Mixture control: characteristic controlled injection system with sensors for rotational speed, oil temperature, throttle control position, air temperature, air pressure and lambda probe

3 bar pressure system in the injection system to avoid vapor lock

Environmental compatibility: 3-way catalytic converter, HC-reduction about 85%; NOx-reduction about 80%


Helical, with hardened and grinded gearwheels. Gear reduction: (2,46; 2,75; 3,05, 3,46 :1 possible)

Springless, one-piece centrifugal automatic-clutch (rotational speed of action 2800 1/min)

Rotational oscillation damper (absorbes rotational oscillations of approx. +/- 10°)

Total weight when ready for take off including exhaust system, gear and coolant: approx. 80 kg

No other two-cylinder four-stroke engine has - caused by the pistons working in an opposite manner - a so perfect mass balancing so that the flat engine works without much vibrations even without weight increasing compensation shafts. The mass balancing gets more optimal at higher rotational speed. For the lower speed range the unfavorable traction combination of the degree of non-uniformity of the engine and the moment of inertia of the propeller is decoupled by a centrifugal clutch.

A rotary oscillation damper prevents resonances between engine, gear and propeller.