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).
Report page investigating crank units and bending theory, comparing different balance mass systems.
| Identifier | ExFiles\Box 132\1\ scan0090 | |
| Date | 2nd November 1938 | |
| - 2 - BY/B.8/G.2.11.38. (a). With no balance masses. (b). With the RR. system of balance masses, and (c). With the 'Packard' system. Further tests to determine the average M.{Mr Moon / Mr Moore} of I. of a crank unit in the two directions would be very useful, so as to provide a sure basis for the numerical results of the above investigation, when completed. Using my theory of crank bending of 4.4.38. and arbitrarily assuming the effective length of web to be .9, the M.{Mr Moon / Mr Moore} of I's for radial and tangential bending came to I_R = .158 inch 4 units. I_T = .211 " " I_T agrees closely with, but I_R is considerably greater than the value overleaf determined indirectly from crankshaft tests. It is clear that a crank is relatively very flexible in bending in a radial plane, and that webs should be as thick as possible, consistent with bearing requirements, or even perhaps at the sacrifice of some bearing length. BY/B. GBBower. | ||