BMW IIIa
BMW IIIa | |
---|---|
The Smithsonian National Air and Space Museum's preserved BMW IIIa, shown with quick-change propeller hub | |
Type | Inline engine
|
Manufacturer | BMW |
First run | 1917 |
Major applications | Fokker D.VII |
BMW IIIa was an
Design and development
On 20 May 1917,
The military authorities were responsible for the fact that the first BMW product was designated with a III instead of an I. As early as 1915, the
The engine was successful, but the real breakthrough came in 1917, when Friz integrated a basically simple throttle butterfly into the twin-barrel "high-altitude carburettor", enabling the engine to develop its full power high above the ground. Burning a special high
German and British horsepower ratings apparently differed. Postwar British tests put the rating of the BMW IIIa at 230 hp. This corresponds to British ratings of the Mercedes DIIIa engine being rated by the British as 180 hp (German rating of 170 hp) and the DIIIau at 200 hp (German-180 hp). This discrepancy may explain the significant difference in performance of the BMW IIIa equipped Fokker D.VIIF both against Mercedes powered D.VII's and their Allied opponents. The standard German Pferdstärke
The ability to gain power at higher altitudes was why this engine had unique superiority in air combat. It was primarily used in the Fokker D VII and in the Junkers Ju A 20 and
There can be no doubt that the BMW engine was the absolute highlight in power unit development towards the end of the war. The only bad thing was that it came too late.[1]
About 700 engines were built by BMW, however, a large demand for the new BMW IIIa aircraft engine in
On September 13, 1919,
Applications
- Aero A.18
- Aero A.26
- Aero Ae 04
- Avia BH-3
- Fokker C.I
- Fokker D.VII
- Dobi-III
- Junkers D.I
- Junkers F.13
- Letov Š-3
- LFG Roland D.XV
- LFG Roland D.XVII
- TNCA Serie E
Specifications (BMW IIIa)
Data from Smithsonian NASM BMW IIIa specifications
General characteristics
- Type: 6-cylinder, inline, water-cooled, piston engine
- Bore: 150 mm (5.9 in)
- Stroke: 180 mm (7.1 in)
- Displacement: 19.085 L (1,165 cu in)
- Length: 170.2 cm (67.01 in)
- Width: 50.8 cm (20 in)
- Height: 105.4 cm (41 in)
- Dry weight: 293 kg (646 lb)
Components
- Valvetrain: SOHC (single overhead camshaft)
- Fuel system: Two-barrel altitude compensating (to 2 km) carburetor
- Cooling system: Water-cooled
Performance
- Power output: 134 kW (180 hp) at 1,410 rpm
- Compression ratio: 6.4:1
See also
References
- ISBN 1-84119-470-0