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BMW based in Munich, were manufacturing
Pratt and Whitney radials under license in the 1930's and used this experience
to develop its own twin row engine. Despite this, it can be considered an
original design incorporating fuel injection and other German features.
It is distinctly different from the
American engines and incorporated MW50 fuel injection, initially methanol-water.
Later engines also had a gear-driven two stage supercharger. The boost could, in
emergency, push the engine output from 1,600 h.p. to around 2,100 h.p. Radial
engines were uncommon in successful European fighter aircraft until the BMW 801
was used in the Focke-Wulf Fw 190, with armored oil tank and powerful cooler
gear in the cowled nose section and multi-stack ejector exhaust.
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The BMW 801D-2 was fed by methanol-water injection.
Most revolutionary however, was the hydraulic-electric 'brain' unit,
operated by a single control which was the pilot's throttle lever. It
automatically adjusted fuel flow, mixture strength, propeller pitch
setting and ignition timing. It also cut in a second stage of the
supercharger at the correct altitude. The pilot could, if required,
manually set the propeller pitch without altering any of the other
settings. |
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A remarkably compact installation, adequate cylinder
cooling was obtained using pressure baffling augmented by a magnesium alloy fan
geared to turn at 1.72 times engine RPM (3 times propeller speed). An oil tank
and cooler are positioned in the nose bowl and are armor plated. The engine
mount ring is a sealed unit of square cross-section and also acts as a hydraulic
fluid reservoir. Additional streamlining was achieved by the introduction of
drag-inducing cowl flaps.
The Focke-Wulf
Fw-190 ranks with the Supermarine
Spitfire,
Vought Corsair
and North American
Mustang as one of the best fighters of World War II. This
would not have been possible without the powerful BMW 801 engine.
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Aircraft
