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).
Pressure testing an oil cooler, detailing test results, failures, and proposed modifications.
| Identifier | ExFiles\Box 131\1\ scan0249 | |
| Date | 1st December 1936 | |
| -2- Rm{William Robotham - Chief Engineer}/Std.11/AP.1.12.36. With regard to the severity of the test - the test was instituted before we had the latest Ph.III. crankcase, relief valve and oil pump etc - test bed figures taken then indicated a possible pressure with cold oil of 110 lbs/sq.in. We have checked up on the maximum pressure encountered on the cooler by racing the engine with Motorine C. oil at 0°C. and found this to be 65 lbs/sq.in. - further the drop across the cooler was only approximately 10 lbs/sq.in. In view of this, our tests appear to be more severe than necessary - however we think that they should be retained until we are satisfied that Marstons are using good enough production methods to stand these pressures - we can then drop the specified pressures to 130 lbs/sq.in. cold and 100 lbs./sq.in. with oil at 130°C. We also think however, that in view of the serious nature of oil cooler failure, we should endeavour to reduce the maximum pressure to which the oil cooler will be subjected, primarily this should be done by further reducing the restriction of the relief valve i.e. making it act as a genuine pressure control under all conditions. We are also going to experiment with the cooler on the suction side of the pump. A further trouble which was experienced from Messrs Marston's point of view was distortion of the union seatings during pressure tests. This was overcome to a large extent by making machining of these faces the final operation - however, the stiffened top plate to E.88558 which By.{R.W. Bailey - Chief Engineer} has given us should help in this direction. Rm{William Robotham - Chief Engineer}/Std. Sketch att | ||