Green D.4
| D.4 | |
|---|---|
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| Type | 4-cylinder water-cooled inline upright piston engine |
| National origin | United Kingdom |
| Manufacturer | Green Engine Co. Ltd, London |
| Designed by | Gustavus Green |
| First run | 1909 |
| Developed from | Green C.4 |
The Green D.4 was a four-cylinder watercooled inline piston engine produced by the Green Engine Co in the UK in 1909. It produced about 60 hp (45 kW) and played an important role in the development of British aviation before World War I.
The Green D.4 was a natural development of the Green C.4, a 30-35 hp engine used by some early aviators in the UK, such as Roe and the Short Brothers. It was an inline, water-cooled 4-cylinder piston engine with characteristic Green features: cast-steel single-piece cylinders and cylinder heads, two valves per cylinder driven by an overhead camshaft, white metal crankshaft bearings and copper water jackets, rubber-sealed to allow for differential expansion.
Increases in bore and stroke gave the D.4 more than twice the swept volume of the C.4 and roughly doubled its power. The cast-steel cylinders, individually machined inside and out, were mounted separately onto a flat-sided aluminium crankcase. They were fastened down by long bolts between them, which reached into the crankcase to support the four inner crankshaft bearings. The main bearings were in the crankcase ends, and the ball race was designed to allow either pusher or tractor operation. A flywheel was fitted to the output shaft. Thin cylindrical copper water jackets surrounded the cylinders almost to their base, where a rubber ring, located by a circumferential groove in the cylinder, provided a sliding water seal that allowed for the differential thermal contraction of copper and steel. Cooling water was fed to these jackets by an engine-driven pump via a horizontal tube on the low right side of the engine, assuming a tractor orientation, and fed to the radiator by another tube on the top left.
A single jet Zenith carburettor with a remote float chamber fed a double branched inlet manifold on the right; the plugs, also set in the cylinder walls, were on the same side, below and angled to the inlets. The exhaust ports were on the left side, angled forwards. A crankshaft driven Bosch magneto at the rear provided the plugs' high voltage supply. The overhead camshaft was also driven from the crankshaft via worm gears and a vertical shaft at the rear of the engine. The camshaft operated the valves by rockers with rollers on their camshaft ends and adjusting screws at the other.
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Wikipedia