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).
Technical analysis of engine bearing loads and P.V. factors, comparing different balance configurations and a Bentley V engine.
| Identifier | ExFiles\Box 115\2\ scan0498 | |
| Date | 26th October 1939 | |
| -2- the centre bearing diagram this effect appears as kinks at about 20° and 200°. The main bearing diagrams were drawn initially with 79% of the rotating matter balanced. This meant that the webs and crank pins were completely balanced. An additional 11% was tried in order to find how far the load on the centre bearing could be reduced by this means. Maximum P.V. factor at 4500 r.p.m. due to inertia and gas pressure with 79% balance is 29,900 for the outer bearing and 61,000 for the centre bearing. This latter figure is reduced to 55,000 by increasing the balance to 90%. By/B.6/G.5.12.38. gives a figure of 43,200 at 3500 r.p.m. for the most severly loaded Bentley V main bearing. Since at high speeds the maximum loading is largely due to inertia which is proportional to (speed)^2 the P.V. factor is approximately proportional to (speed)^3. Hence the factor for the centre bearing at 3500 r.p.m. would be approx. 28700 to compare with 43200 for the worst Bentley V bearing. Engine Data. Diagram Dimensions: Top: 1.05", 1.25" Bottom: 2.3", 3.3", 2.1", 2.1", 3.3", 2.3" | ||