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).
Performance and top speed of a Bentley car, compiling extracts from various reports.
| Identifier | ExFiles\Box 160\5\ scan0084 | |
| Date | 17th December 1940 | |
| COPY. Sg.{Arthur F. Sidgreaves - MD} re:- Bentley Publicity. Cx.{Major Len W. Cox - Advertising Manager}3/KW.17.12.40. I have received your Sg.{Arthur F. Sidgreaves - MD}6/KW.10.12.40. with enclosure from Rm{William Robotham - Chief Engineer}, which I have carefully studied. Whilst I too was disappointed with the figures published, I do not think we could have expected anything else. In support of this remark I would merely like to remind you and Rm.{William Robotham - Chief Engineer} of what several people have written or said about the performance of this car, and I accordingly give below the following extracts :- Professor Dodds - he wrote in July last : "With regard to maximum speed, I was unable to get the car over 90 m.p.h. despite most favourable conditions. The road I took was wellknown to me, and I had been over it often in my own car. I had an ideal road when I struck it, as there was nothing in sight, and there are no cross-roads. I was still unable to get the car to go more than 90 miles. In my own car I could guarantee to get up to 95." Sclater Booth. - wrote in July 1940 : "The maximum obtained was 90 m.p.h. on the speedometer, which presumably means somewhere about 86 m.p.h. over the ground." My. first Report 10 th. October 1938 reads : Dealing with the performance, I venture to suggest that the engine is not giving off its proper horse-power. If it is, then the performance is not one which we could "put over" to the Public. I found it was quite a difficulty to get the engine up to its 4,500 revs on second gear, and impossible even on third. The best speed on third gear with wind and gradient in favour of the car was 83 on the speedometer, which, allowing for error, is about 80. The car is geared to do 91 on that gear. On the overdrive under the most favourable circumstances the speedometer just struggled up to 90, which I suggest is about 86 true. My feeling is that, if this engine represents the best power output we can get, we shall need to make it about 4 1/2 litres in order to get the performance which I think this car ought to have, and I have in mind that it should at least reach 100 m.p.h. under normally favourable conditions. Another report made by me in May 1940 reads : The speed under normal conditions on the level seems limited to about 90, and it wants favourable circumstances of gradient or wind to get the needle beyond the 90. I still adhere to my original remark when - Continued - | ||