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).
Letter from 'The Autocar' magazine detailing their method for testing car braking distances.
| Identifier | ExFiles\Box 142\3\ scan0017 | |
| Date | 23th November 1936 | |
| 1204 MARTINDALE The Autocar The Leading Motoring Journal PROPRIETORS: ILIFFE & SONS LTD. Telegrams: AUTOCARS, SEDIST, LONDON. AUTOPRESS, BIRMINGHAM. AUTOCAR, COVENTRY. ILIFFE, MANCHESTER. ILIFFE, GLASGOW. Telephones: LONDON: WATERLOO 3333 (50 LINES) BIRMINGHAM: MIDLAND 2971 (4 LINES) COVENTRY 5210 MANCHESTER: BLACKFRIARS 4412 (4 LINES) GLASGOW: CENTRAL 4857 BIRMINGHAM: GUILDHALL BUILDINGS, NAVIGATION STREET. COVENTRY: 19, HERTFORD STREET. MANCHESTER: 260, DEANSGATE, 3. GLASGOW: 26B, RENFIELD STREET, C.2. Dorset House, Stamford Street, London, S.E.1. IN REPLY PLEASE QUOTE REF. A/GS/HJJ 23rd November, 1936. Messrs Rolls-Royce Limited, D E R B Y . For the attention of the Experimental Department. Dear Sirs, In reply to your letter of the 18th instant, after many tests by various methods, we have found hand timing the most reliable. In the issue of 1st May 1936 in an article discussing the shortest distance in which a car can be stopped from a given speed and explaining why practice beats theory, you will find our procedure detailed, but briefly, we set the car at a steady 30 m.p.h. by corrected speedometer reading, approaching a mark in the form of a post at the side of the track or road, or alternatively a painted line across the track, applying the brakes when the driver becomes opposite the post or line. He takes a sight on the mark relative to some suitable fixed point on the car. Naturally the test is repeated several times to secure a reasonable consistency, and an average is then struck of the readings. Yours faithfully, Geoffrey Davitu MANAGING EDITOR. | ||