With considerable interest have I read the article “Restoration of the Decade” in the June 1970 issue of your magnificent publication.
My own preoccupation with old engines lays in another field since I have dedicated many years of earnest research to the history of the piston aero engine. Most of the outstanding aero engines have been designed as you also know, by men related to the motor car industry, yet the aero engine is not a car engine not even a glorified one.
As a result, I’m sorry to say, aeroplane enthusiasts regard the engine as another accessory of the plane, worth a few lines in a general description, but the automobile historians, who should be more interested, stop short as soon as one of the engines, on which they usually are very well documented, becomes extrapolated for aeroplane use, apparently reluctant to enter a field outside their scope.
As a result, the aero engine, although the most brilliant member of the internal combustion engine family, has had its history somewhat neglected.
Now to the point: Mercedes No. VI (page 620) should also be the famous car that was used by the Rolls-Royce designers as basis for their first aero engine. This first 6-cylinder Rolls-Royce was quickly enlarged to a V-12 which later became famous as the “Eagle”. Rolls-Royce will be the last to deny the Mercedes ancestry of their aircraft engines but in aero engine technology, construction is more important than invention and possible ancestries of any given successful engine really are of little matter except for patriotic reasons.
Your sentence “possibly being driven to Derby” must refer to the claim by W. O. Bentley as related in Harald Penrose’s “British Aviation 1915-1919” (Putnam t969). There one finds that “Bentley and Briggs found a 1913 (?) Mercedes in a London Showroom (Long Acre?), then drove it to the Rolls-Royce factory at Derby where they convinced Ernest Hives (Lord Hives) that it had the type of cylinder construction required for aero engines, but that aluminium pistons should be used instead of cast-iron. Henry Royce’s technical assistants, A. G. Elliott and Maurice Olley, accepted these proposals and initiated preliminary design of a prototype 12 cylinder engine of 175 HP” (page 227).This would be simple if another and earlier publication (Frederick Henry Royce by G. Geoffrey Smith) had not told us a different story, here it goes: “Reverting to the (Mercedes) Grand Prix car of 1914, it was obvious that time had not permitted the return of this car (one of the race cars rushed over by the Mercedes Company to their London Showrooms) to Germany, and a diligent search resulted in its being found hidden in a cellar. The car was dispatched to the works at Derby, where Royce had the power output carefully tested … It was then dismantled, its features-examined, and careful drawings and records taken. Afterwards it was reassembled and tested, until breakdown occurred, to ascertain its weakest parts. Using the design as a basis, he built a similar engine … ” etc.
One wonders what is the real truth of those versions. And one wonders still more how and when a car, or engine that had been tested until breakdown occurred, was put together again so that it could be sold in 1919?
Of course the two stories could be made to coincide, it was perhaps Bentley who found it hidden in a cellar and then drove it to Derby? If you know more about that episode I will be happy to hear it.
HUGO T. BYTTEBIER – Buenos Aires
[See also references to Mercedes cars and Rolls-Royce aero engines in back issues of Motor Sport – Ed.]