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).
Replying to a memo about overheating on 40/50 cars, specifically concerning the fitting of 4-wheel brakes.
| Identifier | ExFiles\Box 24\5\ Scan018 | |
| Date | 28th April 1925 | |
| H.H. 499a (50m) (D.B. 175 25-9-24) J.H.D. X766 EXPERIMENTAL REPORT. Expl. No. REF. Hs{Lord Ernest Hives - Chair}5/LG28.4.25. To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} To CJ. " " To BJ. " " To Wor.{Arthur Wormald - General Works Manager} " " RE. OVERHEATING ON 40/50 CARS. 46990 X766 Referring to CJ1/E27.4.25. With reference to the questions asked in the above memo., the following are the Experimental Dept: replies :- (1) Yes - Comparative measurements were taken of the heat given out to the water with two types of exhaust system. In our opinion this is the only test necessary because in fitting 4-wheel brakes to the existing 40/50 HP. cars, the cooling arrangements of the car were not altered in the least. This includes, radiator, fan, ventilation and water pump. The amount of heat given by the engine to the water could be influenced by the modification to the exhaust system but no difference in maximum heat conditions could be be measured. (2 / 3) These have been replied to in our memos. Hs{Lord Ernest Hives - Chair}/Rn{Mr Robinson}/LG 9.4.25 and Hs{Lord Ernest Hives - Chair}6/LG27.4.25. We explain that cars fitted with 4-wheel brakes may, under certain conditions, be slightly worse for over-heating. It would depend upon how the car was driven and whether the setting of the choke valve was correct; so far, we should not expect the difference to be more than 5%. It should not make the maximum conditions any worse. There is another point, that is, a car with 4-wheel brakes could use a greater percentage of full power and in consequence heat more water. As an instance, on a hill like La{L. A. Archer} Turbie, if one assumes that the corners will be taken at the contd :- | ||