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).
Vehicle acceleration, engine performance, and braking systems.
| Identifier | ExFiles\Box 21\7\ Scan030 | |
| Date | 23th October 1925 | |
| R.R. 493a (50 H) (D.D. 31, 12-6-25) J.H.D. EXPERIMENTAL REPORT. -5- Expl. No. REF Hs{Lord Ernest Hives - Chair}/Rml/LG/231025 Above 25 m.p.h., the acceleration is very fair. The speedometer was of the Hispano type, and moved at given intervals, in addition we had no opportunity of checking it, it was therefore impossible to get even approximate accelerations. We timed the car by up Brockley Hill from 10 m.p.h. at the bottom. The climb was made on in 58 secs., max. speed 40 m.p.h. - finishing 26 m.p.h. (by the speedometer). Average figures for the same climb by a Phantom are - 49 secs. - 47 to 50 m.p.h. - 34 or 35 m.p.h. The engine was rougher than a Phantom R-R throughout its whole range but not definitely obtrusive until over 45 m.p.h. on 3rd. gear when a period came up. There was also a slight period at 40 m.p.h. on top gear. We had no opportunity of trying the max. speed of the car. BRAKING. The brakes on this car are not nice to handle. At low speeds there is no assistance from the hydraulic servo, direct braking being relied upon. Considerable pedal pressure is required. There is no lag when shunting normally as all the braking is then direct which appears to be equally bad backwards and forwards. The pedal (or brake linkage) has a very strong return spring. At high speeds the servo is very effective and it is most difficult to detect when the foot is pushing ga against the return spring and when closing the servo valve. The whole action gives a driver who contd :- | ||