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).
Tests carried out on an experimental pressurized cooling system fitted to car model 39-EX.
| Identifier | ExFiles\Box 131\1\ scan0309 | |
| Date | 1st September 1937 | |
| By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/Std. c. Hs.{Lord Ernest Hives - Chair} c. Da.{Bernard Day - Chassis Design} c. Mx.{John H Maddocks - Chief Proving Officer} REPORT ON TESTS CARRIED OUT ON COOLING SYSTEM OPERATING UNDER PRESSURE, AS FITTED TO 39-EX. This car is fitted with an entirely experimental cooling system - this system was designed and built with a view to reducing the weight of the radiator considerably, and while retaining a satisfactory standard of cooling under all conditions, a certain reduction of cost should also be obtained with this system. The system was designed to run with coolant leaving the engine at temperatures up to 117°C (12 lbs. sq.in. pressure) and is therefore able to use a smaller radiator matrix than the standard Ph.III. car. The starting handle tunnel is omitted from the matrix, the starting handle passing below the bottom tank, which is a pressing. A special steam valve is fitted to the top tank, set to blow at 12 lbs/sq.in. The radiator complete weighs approximately 30 lbs. less than the standard article, the % weight saving being approximately 23%. Weight and cost savings have also been made on the engine by omitting the top water rails and fitting outlets to the ends of the cylinder heads. The drain cock is situated on the water pump cover instead of on the radiator outlet. This system was first tried on the test bed where the Ph.III. engine was run for 30 minutes with a water outlet temperature of approximately 112.5C. and a pressure in cooling system of 8 lbs/sq.in. - see report Rm{William Robotham - Chief Engineer}/Std.15/AP.22.4.37. No trouble with engine was experienced and the only trouble with the radiator (which was in circuit during the tests) was that the steam valve leaked badly throughout the test with the result that a good deal of water was lost; 1 - 2 gallons. No oil cooler was fitted to this engine, but a test bed oil cooler was of course used. It was decided that a steam valve giving a 100% seal was necessary in order to enable the coolant to be run at temperatures above 100°C. without loss taking place. Steam valves of various types were tried (two way valve similar to aero valve A.514, two way valve to Rm.{William Robotham - Chief Engineer}291 with rubber seatings, two way valve similar to Rm.{William Robotham - Chief Engineer}291 but with metallic knife edge continued | ||