aero and automotive engines and engineers
Some details of the 1941 Armstrong Siddeley 24 cylinder Wolfhound aero-engine project
by Richard Hodgson.
Cylinder and head generally similar to the Deerhound Mk.111, but scaled up;
Piston similar to the latest Deerhound Mk.111, but an additional 10mm longer;
Direct air cooling of exhaust valve guide by air ducts within the head itself;
2800 rpm engine speed - higher than previous practice to help with detonation;
Head to barrel had been a weak link on the Deerhound Mk.111. If required, integral barrel and head in aluminium alloy, if possible cast and with pre-fabricated fins - as requested for the MK.111 in 1940, but never sanctioned [by the Board!];
Contra-rotating air screw;
Mounting by cantilever suspension picking up from the rear cylinder heads braced by the camshaft covers. Engine designed ab initio in power plant form;
Initial power output 2600-2800hp;
Designed with the possibility of a two-stage supercharger to be designed by W. H. ("Pat") Lindsey [who, sadly, died on 8th May 2000];
There was something very unusual about the eventual poppet valve and spring arrangement, but the form is still unknown - the answer may be in a classified patent application, if any copy still exists.
The discarded earlier Wolfhound 28 cylinder (7 x 4) proposal of Colonel Fell was criticised in 1940 on the grounds of several estimated severe major periods in the running range by Tresilian and J. B. Bucher when they were first considering the design of a engine in the 2500hp range. Part of the aim was to increase cooling space between the cylinder banks. Pressure was put on the Ministry by Bristol and Rolls-Royce to cancel the Wolfhound project during Summer/Autumn 1941. There is some evidence to suggest that the Ministry had [slight] regrets about the cancellation in 1943.
As a matter of record, the only former ASM engineer that I spoke to who immediately recalled the 1941 Wolfhound being a 24 cylinder design was the late John Densham, who had never worked on the project! The late Pat Lindsey told the author in the early 1990's that he knew nothing about the details of the project save for being asked by Tresilian whether he could design a two-stage supercharger for a "new engine" at relatively short notice if required. The answer was yes! (though he was never to be asked to design it). From other Public Record Office papers and a set of papers recently discovered by Patrick Hassle at Bristol, it is possible that much of the early 24 cylinder Wolfhound design work was carried out as a Bucher and Tresilian "private" project.
© 1993, 1994, 2000, Richard Hodgson - may not be reproduced in whole or in part without permission
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