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aero and automotive engines and engineers

This web-site, which only started at the beginning of 2000, will, it is hoped, act as one where information and histories about UK aero and automotive engines and engineers from the 1920's to 1970's can be deposited as well as retrieved.  A major addition of historical importance is the full official law report of the late 1946 trial between Bentley Motors (1931) Ltd  v  Lagonda Ltd and W. O. Bentley.   This site is best viewed using Microsoft Internet Explorer 5.  



The originator of this site, Richard Hodgson, has given talks on certain historical aspects of aero and automotive engineering matters on both sides of the Atlantic, including several to the Bristol, Coventry and Derby branches of the Rolls-Royce Heritage Trust.  He wrote the obituary of W. H. "Pat" Lindsey that appeared in "The Times" [of London] on Tuesday 20th June 2000.  He took his first degree in electrical and electronic engineering and is an intellectual property and e-business law barrister.  Finding little on the Internet concerning, in particular, UK aero-engines and aero-engineers, he decided to start this site as a place where information might be found and requests for information posted.  "Wolfhound" was the name an proposed Armstrong Siddeley piston aero-engine.

He has long had a special interest in the late Stewart S. Tresilian (1904 - 1962).   Tresilian, whose Christian names names were not spelt Stuart, worked on both the car and aero-engine sides of Rolls-Royce (1927 - 1936);  on cars at Lagonda (1936 - 1938) where W. O. Bentley appointed him chief designer (especially for the Lagonda V12 project);  and at Templewood Engineering (1938 - 1939).  Projects at Templewood included an all-aluminium (in fact, "all" light alloy) car with rubber [sic] suspension and a 4 bearing 4 cylinder aluminium sleeve-valve engine.  After a spell at Armstrong Siddeley (see below), Tresilian was the USAAF - RAF engine co-ordinator (1942 - 1945).

He rejoined Rolls-Royce (1945 - 1948) on just the aero-engine side at Hucknall, where he openly ran an unofficial engine design office to the annoyance of Adrian Lombard.  After 1948, when he refused Lord Hives's firm request to return to Derby, he freelanced (at times in a loose partnership with Erling Poppe who had been with - amongst others - Dennis, designed the Sunbeam S7 motor bicycle and then went on to Vernons [the football pools people!] to design a three wheeled car after the partnership came to end), working with BRM and Connaught for a while on racing cars.  He became an assistant chief engineer under Stanley Hooker at Bristol (later Bristol Siddeley) in 1953 working on special projects, including an advanced flying car for the military, consulting for Rover and Coventry Climax, and an all-aluminium ohc high output 4.5 litre V8 car engine in late 1959.  He was still as Bristol Siddeley at the time of his early death in May 1962.   He was the UK patentee of the three or more valve per cylinder form engine where the stroke is about 75% of the bore and of the sliding-tube de Dion axle.  Tresilian was also a sometime racing driver who, in his Bugatti type 35, had some success.  He later drove a type 55.

Though not generally known, he was appointed Armstrong Siddeley's chief engineer in 1939 on the basis of his work at Rolls-Royce, Lagonda and Templewood.  He was just 35 at the time.  Armstrong Siddeley were one of the four major UK aero-engine manufacturers.  The others were Bristol, Napier and Rolls-Royce.  His time at Armstrong Siddeley Motors ("ASM"), which also made well-known cars, was quite remarkable and has been the subject of a lengthy talk about the last ASM Dog Engines and another detailed talk about the beginning of gas turbine work at ASM, both given by Richard Hodgson.   Tresilian, who almost immediately agreed to the cancellation of the large Boarhound radial aero-engine project,  tried to make a go of the highly problematic Mark II Deerhound 1500hp (nominal) 21 cylinder radial aero-engine, as well as offering - in late 1939 [sic] - whatever assistance was required to Frank Whittle's Power Jets company.  His eventual Deerhound part re-design, the Mark III 1800hp (nominal), was a "near miss", coming too late.  Only a GA sketch exists of what is believed to be Tresilian's proposed Deerhound Mark IV, designed, ab initio, in power-plant form.

Matters came to a head at ASM in mid-January 1942 when Tresilian gave his backing to (a) close co-operation with Metropolitan Vickers over the MV - RAE F2 axial turbo-jet [sic] project, (b) further investigations into the gas turbine proposals of T. P. de Paravicini which included UDF - unducted fan - designs [sic], and lastly, (c) a little time to the gas-turbine proposals of one Heppner - see below.  With the benefit of hindsight, the UDF proposals have recently been described by Brian Slatter, de Paravicini's bright post-graduate student, as being unworkable.  Instead, the Board of the parent company, Hawker Siddeley, and Dr. Rowell, by then the company's General Manager, wished to back the flat-out development of complex contra-rotating contra-flow and eventually unworkable gas-turbine designs [the various ASH, not ASX, proposals including a 1943 11,000lb fan unit!] of Fritz A. M. Heppner (sometimes spelt Hepner), a German refugee - see also below.

Tresilian refused to back Heppner and was given a very short time to leave.  He told engineers in the Design Office that "he had upset the apple cart and had to go".  Various other senior engineers also "departed" at that time or shortly afterwards, including T. P. de Paravicini (who went to Bristol) and J. B. Bucher (later to be the technical director at Blackburn gas-turbines).  Some years later, Armstrong Siddeley were to take over the advanced Metropolitan Vickers F9 Sapphire axial turbo-jet project, and under W. F. Saxton, W. H. "Pat" Lindsey and their able axial team, develop it somewhat further and turn it into a very successful production job and valuable licence income from Curtiss-Wright as the J.65.  Pat Lindsey, the last Armstrong Siddeley technical director, sadly died on 8th May 2000.  His obituary, written by Richard Hodgson, appeared in "The [London] Times" on Tuesday June 20th 2000.  An extended obituary will appear here in due course.

Tresilian's last piston aero-engine design for Armstrong Siddeley - only on paper, though some single cylinder work may have been done - was called the Wolfhound.  Design work commenced in 1941.  It was an advanced 6 x 4  24 cylinder radial engine of some 2600 to 2800 hp output designed from the beginning in power plant form.   The name was adopted from a discarded pre-Tresilian era 28 cylinder 7 x 4 proposal.

At present, no actual drawings have been located of the 24 cylinder Wolfhound, and many of the known details are contained on single sheet in a Ministry of Aircraft Production ("MAP") file at the Public Record Office in Kew.  The engine appears to have been cancelled in October/November 1941 as, amongst other reasons, it was felt that it would not be ready in time to play any useful war-time role and that the post-war future was only with gas-turbines ("jet engines").   However, MAP does seem to have been impressed by what it saw on paper, and ordered that all drawings and other details be handed over to Rolls-Royce with immediate effect.   The late Sir David Huddie of Rolls-Royce recalled seeing some drawings briefly, but, apart from that, the scent goes very cold.  A patent application for the valve-gear (or maybe just the valves) was classified as top secret and no copy has been found - it is quite possible that the application was not allowed to proceed.

Richard Hodgson gave a talk about Stewart Tresilian at Coventry University to the Rolls-Royce Heritage Trust on Monday 8th January 2001.  Several newly discovered documents were referred to in a session following the talk which will be the subject of note and comment in this site in the future.



List of Articles/Talks and Links presently available 

Aero-engine matters in purple; car matters in dark blue;  both aero-engine and car matters in dark red;  list of external web links in dark green


Information and Articles requested

If you have, or wish to post a request for, any information about any matter connected with aero or automotive engineering and engineers, please do let me know.   Information and requests for information do not have to be related to Armstrong Siddeley or Stewart Tresilian, but should be connected with the wider aims of this site as set up at the top.  Present requests are listed below.

Similarly, if you have an article that you consider might be suitable to post here, again please let me know.  Please note that no payment of any kind can be made and that the article's author retains copyright.  To ensure that the wording is not changed, articles can be requested to be posted in Adobe PDF format.  Articles may well be ones that are too long and/or of too specialist interest for general magazine or even book publication.


Specific Requests for Information, Photographs and Drawings about:
Please click the red REPLY to bring up an e-mail answer box


As already stated, this site has only relatively recently started (5th January 2000) and its originator also has a professional practice to attend to as well, so at times it may not be updated that often and typographical errors are bound to have crept in - notification of which is gratefully received.


2000 Richard Hodgson - may not be reproduced in whole or in part without permission

Fax: + 44 (0)20 7353 0722


The sort of car - in general terms - that Stewart Tresilian (in)famously drove from Slough to Leamington Spa in just over the hour in about 1938!