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).
Saving weight and cost on car radiators by reducing the matrix size on Bentley models.
| Identifier | ExFiles\Box 150\3\ scan0050 | |
| Date | 28th September 1936 | |
| To E.{Mr Elliott - Chief Engineer} C. to Wor.{Arthur Wormald - General Works Manager} C. to Ey. C. to Da.{Bernard Day - Chassis Design} X1280 Hs{Lord Ernest Hives - Chair}/Std.2/JH.28.9.36. Saving Weight & Cost on Car Radiators. We have been summarising the position of cooling etc. on our cars at the moment, and attached are remarks thereon. (1) Bentley. We have been looking into the question of reducing the matrix size on Bentleys and are of the opinion that this can definitely be done. Our calculations are based on critical air temperatures measured at Brooklands with the present standard matrix and a 52 m.m. Mark VI type matrix, using a 3 1/2 Litre Bentley engine. With the 52 m.m. Mark VI matrix and 3 1/2 Litre engine, the critical air temperature under full throttle full speed conditions, without any pressure in the cooling system, was 52°C. Allowing for the increased heat to jacket water with a 4 1/4 litre Bentley engine, the critical air temperature under the same conditions would be 44.5°C. However, the radiator escape valve is spring loaded to blow at 2 lbs./sq.in., hence the actual critical air temperature under the last conditions would be 48°C. In our opinion the car would be overcooled in this condition particularly with a car of the Bentley type which is rarely driven for long periods under low speed full throttle conditions ( the low speed critical air temperature is generally slightly lower - 2-3°C - than the full speed one ) and is unlikely to be driven for long at full speed in climates where the air temperatures is 42°C. or 108°F.{Mr Friese} Examination shows that on the recent 15,000 mile test in France on 6-B-IV with an air temperature of 32°C, the water temperature never exceeded 82°C. under any conditions. | ||