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).
Analysis of engine inertia loads, vibrations, and unbalanced forces for different crank configurations.
| Identifier | ExFiles\Box 132\2\ scan0199 | |
| Date | 29th August 1940 guessed | |
| - 4 - Since successive cranks are nearly opposite each other in engine (P) it is expected that the inertia loads on the main bearings will be small, but detailed calculations must be made; especially so in the case of the end bearings. The angle β = 22½° between the planes of Cranks 2 and 3 and 1 and 4 is recommended because it practically eliminates the otherwise large 8th order 1 node vibration, and reduces somewhat the 11th order 2 node vibration, and also because it is favourable to the main bearing loads and to the anti-couple balance weights required. The irregularity of firing intervals is not expected to be noticeable. At 2200 r.p.m. there will be a secondary unbalanced force, acting horizontally of 3980 lbs. in engine (∝) and 5210 lbs. in engine ( P ). Wd{Mr Wood/Mr Whitehead}/G.S. Bower. .O.T.S. | ||