10 Facts About BMW 801

BMW 801 was originally intended to replace existing radial types in German transport and utility aircraft.

The BMW 801 radial pioneered the use of what would today be designated an engine control unit: its Kommandogerat engine management system took over the operation of several aviation engine management control parameters of the era, allowing proper operation of the engine with just one throttle lever.

The BMW 801 132 was widely used, most notably on the Junkers Ju 52, which it powered for much of that design's lifetime.

BMW 801 139 was originally intended to be used in roles similar to those of the other German radials, namely bombers and transport aircraft, but midway through the program the Focke-Wulf firm's chief designer, Kurt Tank suggested it for use in the Focke-Wulf Fw 190 fighter project.

Tank's solution for the BMW 801 139 was to use an engine-driven fan behind an oversized, flow-through hollow prop-spinner open at the extreme front, blowing air past the engine cylinders, with some of it being drawn through S-shaped ducts over a radiator for oil cooling.

The BMW 801 retained the 139's older-style single-valve intake and exhaust, while most in-line engines of the era had moved to either three or four valves per cylinder, or in British use for their own radials, sleeve valves.

One key advancement for the BMW 801 was the Kommandogerat, a mechanical-hydraulic unit that automatically adjusted engine fuel flow, propeller pitch, supercharger setting, mixture and ignition timing in response to a single throttle lever, dramatically simplifying engine control.

BMW 801 was a radial engine with two rows of seven cylinders.

BMW 801 was cooled by forced air from a magnesium alloy cooling fan, 10-bladed in the initial models, but 12-bladed in most engines.

Design of the BMW 801's cowling was key to its proper cooling, which BMW designed and built themselves and supplied with the engine.