Chrysler A57 multibank
| Chrysler A57 Multibank | |
|---|---|
 | |
| Overview | |
| Manufacturer | Chrysler |
| Layout | |
| Configuration | Multibank |
| Displacement | 1,253 cu in (20.5 L) |
| Cylinder bore | 3.4375 in (87 mm) |
| Piston stroke | 4.5 in (114 mm) |
| Compression ratio | 6.2:1 |
| Combustion | |
| Fuel system | Naturally aspirated (i.e., unsupercharged), Carter TD-1 carburetors[1] |
| Fuel type | Gasoline |
| Cooling system | Liquid |
| Output | |
| Power output | 370 hp (276 kW) @ 2400 rpm |
Created in 1941 as America entered World War II, the A57 Multibank engine was born out of the necessity for a rear-mounted tank engine to be developed and produced, in the shortest time possible, for use in both the 109 examples built of the M3A4 Medium Tank, and the 7,499 examples built of the M4A4 variant of its successor, the M4 Medium tank, each of which had lengthened hulls to accommodate them.
In order to use existing tooling, five Chrysler 250.6 cu in (4.1 L) (bore 3.4375 in or 87 mm, stroke 4.5 in or 114 mm)[1] L-head inline six cylinder engines were arranged around a central shaft, producing a unique 30-cylinder 21-litre (1,253 cu in)[1] engine in a relatively compact but heavy package. The crankshafts were fitted with gears, which drove a sun gear arrangement.[2] With iron block and head,[1] it featured Carter TD-1 carburetors[1] and 6.2:1 compression ratio,[1] for an output of 370 hp (280 kW) at 2400 rpm.[1] It necessitated a longer hull (same as the M4A6),[3] becoming the M4A4;[3] most of these were supplied to Allied countries under Lend-Lease.[3]
In the February 1944 issue of the magazine Popular Science, an advertisement by Chrysler claimed the A57 could still move the tank it was fitted in even if 12 out of its 30 cylinders were knocked out.[4]
The M4A4 was largely supplied to the British, the US preferring the M4A3 with the more conventional Ford GAA V8 engine (when an alternative to the original R-975 air-cooled radial engine was used), and restricting their M4A4s to overseas use. Of course, in wartime, all M4 Medium tanks were used overseas, other than those reserved for training in the United States.[5]
Museum display
The engine was preserved at the Walter P. Chrysler Museum in America[6] and at the Imperial War Museum Duxford in the United Kingdom.[7]
References
- ^ a b c d e f g Berndt, Thomas (1993). Standard Catalog of U.S. Military Vehicles. Krause Publications. p. 193. ISBN 0-87341-223-0.
- ^ Berndt, p.190.
- ^ a b c Berndt, p.192.
- ^ Popular Science, February 1944, p.7. https://books.google.com/books?id=oiUDAAAAMBAJ&printsec=frontcover&source=gbs_summary_r&cad=0_0#PPP1,M1
- ^ Fletcher The Universal Tank, p 70
- ^ "Walter P. Chrysler Museum closing today", Autoblog, December 31, 2012
- ^ John Christopher (2014), Sherman M4 Medium Tank the War Machine, Amberley Publishing Limited, p. 28, ISBN 1445638762
External links
- The Chrysler A57 Multi-Bank Engine - An amazing engine by Julian Edgar of AutoSpeed.
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