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 maximum speed testing of three 3.5 Litre Bentley cars at Brooklands Track, comparing different wing types.
| Identifier | ExFiles\Box 3\4\ 04-page378 | |
| Date | 4th July 1933 | |
| To Sg.{Arthur F. Sidgreaves - MD} from Ha/Lid.{A. J. Lidsey} c. or. E.{Mr Elliott - Chief Engineer} c. Da.{Bernard Day - Chassis Design} RY. c. EV.{Ivan Evernden - coachwork} Ha/Lid.{A. J. Lidsey}3/Kr.4.7.33. 3½ LITRE BENTLEY - BROOKLANDS TRACK. We have tested three Bentley cars (Viz. 2.Z.IV., 3.S.IV., and 4.S.IV.) for maximum speed on Brooklands. The main object of the test was to get a value for the new type domed front wings, (which have proved themselves good in wind tunnel tests) as compared with the flared type wings as originally fitted to the green car - 2.Z.IV. During a previous visit to the track the best lap speed obtained on this car was 83.84 m.p.h. After fitting the new type front wings, the lap speed was increased to 86.46 m.p.h. The wings, therefore, are worth 2.62 m.p.h. The two other cars are fitted with flared wings but they are 2.5" lower than the flared wings originally fitted on the green car 2.Z.IV. We should not expect therefore that the same increase in speed would be obtained on 3 and 4.S.IV. by fitting the new domed type wings. Lap speeds obtained on 3. S.IV. and 4. S.IV. are as follows :- 3.S.IV. - 86.02 m.p.h. 4.S.IV. - (1) Windscreen fully erected 86.28 m.p.h. (2) " half down 87.38 m.p.h. (3) " fully down and tonneau cover fitted. 88.00 m.p.h. N.B. All tests with cut-out open. The open car was fitted with a high geared axle (11/45) - i.e. 5% higher than the other two cars - and the engine had a compression ratio of 7.25:1 All these three cars represent, to all intents and purposes, the production Bentley, so that it is reasonable to assume that the production cars should have a lap speed of 86 m.p.h. On the way down to the track a maximum road speed test was made, the results of which are worth recording. | ||