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).
Comparing braking and acceleration figures for a Phantom against other vehicles.
| Identifier | ExFiles\Box 69\4\ scan0307 | |
| Date | 14th December 1925 | |
| R.R. 493A (50 H) (D.D. 31, 12-6-25) J.H.D. EXPERIMENTAL REPORT. -2- Expl. No. REF:Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}/LG1412125 The braking figures are very interesting. The results for the Phantom seem remarkably consistent, but they are some 20% better than anything which we have obtained. Neglecting the figure of 21 ft. from 30 m.p.h. for the Vauxhall, which is palpably absurd, there seems little to choose with regard to efficiency apart from effectiveness of operation, between the two sets of brakes. We consider we shall have to make some tests on maximum braking efficiency apart from our usual tests with no wheels locked, to see if we can substantiate some of the astonishing results which we have recently been given, notably those of Mr. R.{Sir Henry Royce} Minchin's car. It should be noted, however, that the Dunlop Co. have also taken a large number of scientifically accurate braking tests and state that a retardation exceeding 20 ft/sec2 is very exceptional. With regard to the indirect gear acceleration figures, we consider that it is quite useless to compare the Phantom with any sports car, while it is equipped with its present type of gear change. As we demonstrated on Brooklands, see (Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}/LG8.7.25), a large amount of time is lost changing up due to no vigorous stop being fitted as is usually the case on these ultra-sports cars. In any case, as the Vauxhall cannot be accelerated from below 20 m.p.h. on top gear we should expect it to gain something on the indirect gears. contd :- | ||