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).
Cooling tests carried out on a 1.B.IV. car at Brooklands to determine the optimal bypass pipe size.
| Identifier | ExFiles\Box 131\5\ scan0003 | |
| Date | 1st November 1937 | |
| r 11/16 To By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/Std. c. to HS.{Lord Ernest Hives - Chair} c. to Da.{Bernard Day - Chassis Design} c. to Mx.{John H Maddocks - Chief Proving Officer} Report on Cooling Tests carried out on 1.B.IV. car at Brooklands. These tests were made in order to determine the maximum size of pipe which could be used for the separate bypass pipe from the thermostat casing to the water pump – this being the scheme which is being experimented with for the Bentley. The tests were made in the usual manner at Brooklands – maximum speed and 30 M.P.H. figures being taken – the results are shown on attached sheet (1). Some readings of maximum water pressures with various sizes of bypass pipe are also shown on sheet (1). CONCLUSIONS. The critical air temperature of the Bentley car with latest type Mk.V.1. matrix will be satisfactory if either a 7/16" dia. or ½" dia. pipe is used. In view of the fact that the respective maximum water pressures are 33, 25, and 20 lbs/sq.in. with 7/16", ½" or ¾" dia. bypass pipes, we think that the best compromise is a ½" bypass pipe. SUMMARY The best compromise would appear to be a separate ½" bypass pipe from the thermostat casing to the water pump inlet, retaining the standard hot spot water feed. Rm{William Robotham - Chief Engineer}/Std. | ||