|Mercedes D.IVa at the Deutsches Museum. The prominent black piping is the inlet manifold from the carburetor|
|Type||Inline piston engine|
|Manufacturer||Daimler Motoren Gesellschaft (DMG)|
Design and development
The D.IVa replaced the failed Mercedes D.IV inline eight-cylinder engine. The D.IVa was primarily used to power bombers and large reconnaissance aircraft. Unlike most German designs, the D.IVa was relatively advanced, including four valves per cylinder powered by an overhead cam, also used on the earlier two-valve per cylinder D.I through D.IIIa powerplants.
Designed specifically to be installed in the fuselage, the engine featured a number of design elements intended to reduce its width. For instance, the carburetor was placed behind the engine, feeding fuel to the cylinders via a long tubular intake manifold. This had the disadvantage of poor fuel distribution. Two versions of the engine were produced in mirror copies, running in opposite directions.
Engines on display
- A Mercedes D.IVa recently restored by the Museum's Friends ASSN. is on public display at the Museo Nacional de Aeronautica (MORON-Argentina).
- Type: 6-cylinder, inline piston engine
- Bore: 160 mm (6.30 in)
- Stroke: 180 mm (7.09 in)
- Displacement: 21.72 L (1,324.92 cu in)
- Length: 1,168.4 mm (46 in) approx.
- Height: 1,968.5 mm (77.5 in)
- Dry weight: 498.50 kg (1,099 lb)
- Valvetrain: Shaft driven SOHC operating twin exhaust and inlet valves with a half compression setting for starting
- Fuel system: Twin jet Mercedes carburettor with automatic mixture control
- Fuel type: Gasoline
- Oil system: Forced feed to bearings and camshaft
- Cooling system: Water-cooled
- Reduction gear: Direct drive, left-hand tractor
- Power output: 187.92 kW (252 hp) at 1,400 rpm
- Compression ratio: 4.94:1
- Fuel consumption: 125 pints per hour
- Specific fuel consumption: 0.415 l/kW/hour (0.545 pt/hp/hour)
- Oil consumption: 0.0297 l/kW/hour (0.0391 pt/hp/hour)
- Power-to-weight ratio: 0.377 kW/kg (0.229 hp/lb)
- Bmep: 741.19 kPa (107.5 psi)
- Related lists
- Gunston 1989, p.101.
- Jane's 1993, p. 299
- Figures were derived from a British bench test of a captured engine.
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