From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
The evolution and high-speed testing of the 'Corniche' Bentley, including challenges with tyre durability.
| Identifier | ExFiles\Box 160\5\ scan0352 | |
| Date | 14th October 1941 guessed | |
| THE EVOLUTION OF THE “CORNICHE” BENTLEY—continued from page 398 set to work to redesign the appearance and convert the body into a commodious four-door saloon, with plenty of luggage-room. The result of his efforts was what the company’s engineers considered to be a very good-looking motor car, and a wind-tunnel model was made. The drag tests were most encouraging since, in spite of the increased body dimensions, the wind resistance figure was exceedingly low. A full-size car was built and confirmed the wind-tunnel tests. Since it had been decided to put the car on the market as a definite model, no liberties could be taken with the power plant at all. Nevertheless, the car in full touring trim, with a driver and passenger, lapped Brooklands at 109½ miles per hour. The car was then taken to France and the continent, where every new Rolls-Royce chassis has been subjected to a run of at least 15,000 miles of high-speed continental motoring. As this car was intended to be especially suitable for the new motor roads, a considerable amount of this run was carried out on the auto-bahnen and autostrada. The major problem which immediately presented itself was that of tyre life. It was almost impossible to get a standard tyre to last more than a few miles if the car was driven flat out. Another disconcerting result was that, if one indulged in a short spurt of speed and then came back to 90 m.p.h., the tyre never got over its high-speed treatment and, if these speed spurts were repeated, it was found that the tyre burst after exactly the same number of miles as would have been the case if the same distance had been covered continuously. With the assistance of the tyre companies, we at once started to do the necessary development work to get a tyre to suit these extreme conditions, and were well on the way to success at the outbreak of war. Unfortunately, even our experienced test drivers took some time to get accustomed to the very high maximum speeds, and the first “ Corniche ” was completely smashed up just before the war started. This was the only example in existence, and it will, therefore, be some time after the war before anyone can once again handle one of these rather surprising vehicles. It seems improbable that there will be any basic difficulty in accustoming the average Bentley driver to speeds of between 100 and 110 m.p.h. on auto-bahnen specifically built for the purpose. The danger lies in such speeds being used without discretion on normal roads. One other point is worth emphasising. Speeds of 100 m.p.h. are frequently claimed for conventional standard touring-cars. Such speeds are very rarely attained. In reviewing the march of progress, it is interesting to remember that the Rolls-Royce “ Phantom I ” had a top speed in still air of something less than 70 m.p.h., and its engine dimensions were 50 per cent. bigger than those of the existing Bentley. There is no doubt that this streamline Bentley is the forerunner of a new breed of motor-car built to take advantage of the changing road-conditions. | ||