Allison V-3420
The Allison V-3420 was a large experimental W-configuration American piston aircraft engine, designed in 1937.
History
In 1937, at the behest of the United States Army Air Corps, the Allison Engine Company agreed to design and build a large-displacement high-power aircraft engine. The resulting V-3420 was essentially a pair of 12-cylinder Allison V-1710 engines mated to a common crankcase with a 30° angle between the inner cylinder banks. The crankshafts of the two V-1710 engines were geared together to drive a common propeller shaft. Most V-3420 parts were interchangeable with those for V-1710-E and -F engines.
The V-3420 had a power-to-weight ratio of 1.6 kW/kg or 1 hp/lb, excellent for its time. It was envisioned as a powerful yet compact engine for several advanced Air Force projects of the day, including the Douglas XB-19, the Boeing XB-39 Superfortress, the Lockheed XP-58 Chain Lightning, and the General Motors P-75 Eagle. As none of these designs reached full-scale production, only about 150 V-3420s were built.
Variants
- V-3420-A16R (-11)[1]
- V-3420-A16L (-13)[1]
- left hand rotation of propeller, single-stage supercharger with single-stage turbocharger and intercooler
- V-3420-A18R (-17)[1]
- V-3420-A24[1]
- Supercharger ratio 7.2:1
- V-3420-B (-23)[1]
- Similar to the -A but with mechanically driven supercharger in two variable speed stages.
Specifications (V-3420-A18R (-17))
Data from Aircraft Engines of the world 1946[1]
General characteristics
- Type: 24-cylinder turbosupercharged double-"Vee" liquid-cooled piston engine
- Bore: 5.5 in (139.7 mm)
- Stroke: 6 in (152.4 mm)
- Displacement: 3,420 in3 (56 L)
- Length: 97.7 in (2,482 mm)
- Width: 60.0 in (1,421 mm)
- Height: 38.7 in (863 mm)
- Dry weight: 2,655 lb (1,204 kg)
Components
- Valvetrain: Single overhead camshaft per 6-cylinder block, two intake and two exhaust valves per cylinder, sodium-cooled exhaust valves.
- Supercharger: Single-speed one-stage gear-driven supercharger
- Turbocharger: General Electric turbocharger with intercooler
- Fuel system: Bendix-Stromberg PR-58B3 three-barrel injection-type downdraught with automatic mixture control.
- Fuel type: 100/130 Octane
- Oil system: Pressure fed at 60-70 psi (4.2 - 4.9 kg/m²)
- Cooling system: Liquid-cooled with a mixture of 70% water and 30% ethylene glycol, pressurized.
Performance
- Take-off
- 2,600 hp (1,940 kW) at 3,000 rpm at 46.0 inHg / +8.0Lb boost for 15 minutes
- Military
- 2,600 hp (1,940 kW) at 3,000 rpm at 25,000 ft (7,625 m) for 15 minutes
- Normal
- 2,100 hp (1,565 kW) at 2,600 rpm at 25,000 ft (7,625 m) maximum continuous power
- Max. Cruising
- 1,575 hp (1,175 kW) at 2,300 rpm at 25,000 ft (7,625 m)
See also
- Related development
- Comparable engines
- Related lists
References
- Notes
- 1 2 3 4 5 6 Wilkinson, Paul H. (1946). Aircraft Engines of the World. London: Sir Isaac Pitman & Sons Ltd.
- Bibliography
- Bridgman, Leonard. Jane's All the World's Aircraft 1945-46. Hammersmith, London: HarperCollinsPublishers (1994 reprint). ISBN 000 470831-8
- Wilkinson, Paul H. (1946). Aircraft Engines of the World. London: Sir isaac Pitman & Sons Ltd.
