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).
Test report on a car's cooling system, detailing valve performance, fan suitability, and road test results.
| Identifier | ExFiles\Box 131\1\ scan0310 | |
| Date | 1st September 1937 | |
| -2- seatings and a simplified ball valve to Rm.{William Robotham - Chief Engineer}417) and we obtained 100% sealing with the rubber seated type of valve (Rm.{William Robotham - Chief Engineer}291). All other types except the ball valves leaked badly under steam pressure, no matter how carefully they were lapped, cleaned etc. The car was therefore built up with the rubber seated valve fitted and ran satisfactorily for 3-4 months. Temperatures under normal running touring conditions and normal air temperatures being about the same as the standard Ph.III. car. Naturally, no water loss whatever was experienced under these conditions. The valve was removed after this period and tested - its blow off pressure had risen from 11.5 lbs/sq.in. to 15.5 lbs/sq.in. due to sticking of the valve to the rubber seating, further the suction valve had vulcanised itself so firmly to its seating that it refused to open at all. A new rubber seating of the same type was fitted and blow off pressure checked at 12 lbs/sq. in. The car was then fitted with the latest 5 blade Cadillac type fan with 1/1 ratio and taken to Brooklands for radiator suitability tests. Results of these tests are shown on the attached sheet (1). Finally the car was driven back from Brooklands to Derby with the shutters adjusted (practically closed) so that the water temperature ran above 100°C. throughout the journey of 150 miles (air temp. 20°C - 27°C.) The maximum temperature reached on occasions was 114°C. with maximum pressures of 12-13 lbs/sq.in. Average water temp. was 108°C. approx. No trouble was experienced and only approximately 1 1/2 pints of water were lost over the journey. CONCLUSIONS FROM THESE TESTS. (1) The fan drive (1/1 ratio) for the 5 blade fan is not sufficiently good to stand up to sustained high speeds in the standard top gear, but is satisfactory if the overdrive is used. (2) With the overdrive fitted to this car, the cooling will be satisfactory for all conditions if the blow off pressure is 6 lbs/sq.in. corresponding to a maximum temp. without loss of water of 110°C. The corresponding critical air temps. to those shown on sheet (1) attached will be obtained by adding 10°C. to the figures given. continued | ||