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).
Report comparing petrol consumption and performance of two cars, J.B.50 and 28.G.VI, at Brooklands.
| Identifier | ExFiles\Box 111\3\ scan0107 | |
| Date | 16th June 1939 | |
| To Ry. from Rm{William Robotham - Chief Engineer}/Wym.{G. Harold Whyman - Experimental Manager} c. HS.{Lord Ernest Hives - Chair} c. Da.{Bernard Day - Chassis Design} c. Da{Bernard Day - Chassis Design}/LV. Rm{William Robotham - Chief Engineer}/Wym.{G. Harold Whyman - Experimental Manager}6/YE.16.6.39. J.B.50 and 28.G.VI. AT BROOKLANDS. The above 2 cars were taken down to Brooklands Track on Wednesday last for comparative petrol consumption tests and performance tests on J.B.50. J.B.50 car was fitted with Cast Iron Engine Unit B.60 No.4, compression ratio 6.45 : 1, Camshaft EB.4482, Standard Wraith tin plated pistons .010" oversize, Rear Axle ratio 11 x 41, Dunlop Fort Tyres 7.00 x 16, Pressures 45 lbs./sq.in. Weight of car complete - 38 cwts. 0 qrs. 0 lbs. 28.G.VI. standard Wraith engine, compression ratio 6.25 : 1, Rear axle ratio 8 x 34, Dunlop Fort tyres 6.50 x 17. Weight of car complete - 38 cwts. 3 qrs. 7 lbs. Both engines run on Castrolite oil. Petrol consumption figures were taken on the run down to Brooklands, and the return journey, with the 2 cars maintaining similar speeds, and gave the following results:- 28.G.VI. J.B.50. Derby to Brooklands 12.55 m.p.g. 14.84 m.p.g. Brooklands to Derby 13.85 " 14.97 " J.B.50 car was run with Twin and Single exhaust systems and 2 sizes of S.U. carburetters with the results, as shown on attached sheet. Rm{William Robotham - Chief Engineer}/Wym.{G. Harold Whyman - Experimental Manager} | ||