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).
Calculated oil pressure at big ends due to centrifugal force and the effects of bearing leakage.
| Identifier | WestWitteringFiles\N\2October1925-December1925\ Scan260 | |
| Date | 12th June 1925 | |
| R.R. 493A (50 H) (D.D. 91, 12-6-25) J.H.D. EXPERIMENTAL REPORT. -6- Expl. No. REF: Hs{Lord Ernest Hives - Chair}/ACL/LG7.12.25 Graph Title: CALCULATED OIL PRESS AT BIG ENDS DUE TO CENTRIFUGAL FORCE Graph Y-Axis: OIL PRESS lbs/D" Graph X-Axis: R.P.M. If no leakage takes place, the increased pressure in the crank throws will in no way affect the pressure at the bearings 'C' (see previous sketch), but if the bearing clearances are on the large side, considerable loss of oil will take place at points 'B' - and will also increase with speed - as well as a loss admix from point 'A' (which should remain fairly constant). This will result in a loss of 'head' at points 'C' as well as that due to the small friction resistance offered to the oil in its passage through the crankshaft ducts. From our results we can definitely establish the fact that with slack or worn bearings we can reduce the aggregate oil flow, and consequently the consumption, by employing three main oil feeds instead of seven. Of course the extent of the advantage gained will depend upon the bearing clearances and as seen from our first test, no appreciable improvement can be effected if the initial state of the bearings allow only little leakage. We have also made a test to show how the rate of oil discharge through the bearings influences the consumption. For convenience this test was conducted on a 40/50 HP. engine where the rate of flow was varied by means of the oil pressure: The relationship is given by the curve below. contd :- | ||