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).
Investigating oil pressure differences between direct and indirect supply engine bearings.
| Identifier | ExFiles\Box 72\1\ scan0105 | |
| Date | 12th June 1925 | |
| R.R. 493A (50 H) (D.D. 31, 12-6-25) J.H.D. EXPERIMENTAL REPORT. -4- Expl. No. REF HS{Lord Ernest Hives - Chair}/ACL/LG7.12.25 obtained for the previous engine tested. The oil pressure and temperature of oil supply to the bearings (average 60°C) was kept as near as possible constant for each set of tests with both engines. In order to investigate why this difference of behaviour of seven and three bearing feeds existed between the two engines, we were led to determine the actual oil pressure at centre main bearing and the intermediate on either side of it when only the three main bearings were directly fed. To do this an oil-way was continued right round inside each of these three bearings opposite the oil hole in the crankshaft and pressure gauges - previously calibrated relative to each other - attached to these bearings as indicated in this sketch. [Blueprint Diagram Text] Labels on diagram: A, B, B, C, C Labels below diagram: FROM PUMP, 2. INTERM, MAIN, 3. INTERM Text box: At very low speeds the pressure at each bearing did not differ much but as the speed of rotation increased a considerable difference between the main (direct supply) bearing and the two intermediates (indirect supply) became evident. The pressure at the intermediates actually decreased as the speed increased after reaching a max. value at about 500 r.p.m. It will be observed from the curve given below that the main oil pressure also increases with the speed. The reason for this is that at low speeds when the discharge through the bearings is large, no oil passes through the release valve - and only a comparatively small amount at high speeds - consequently the main contd :- | ||