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).
Mr. Burton's calculations for torque variation and stress on the 'Eagle' engine crankshaft.
| Identifier | ExFiles\Box 42\2\ Scan041 | |
| Date | 12th April 1918 | |
| X.3289 To BY.{R.W. Bailey - Chief Engineer} from R.{Sir Henry Royce} c. to CJ. c. to Da.{Bernard Day - Chassis Design} c. to Ell. c. to Wor.{Arthur Wormald - General Works Manager} X.2473 X.2081 12th April 1918. R4/G1441a X.3289.A.RE "EAGLE" ENGINE - CRANKSHAFT. With reference to Mr. Burton's calculations for the torque variation in the crankshaft of the "Eagle", firstly, I think he has done some excellent work on this, for which kindly thank him. We had produced similar diagrams for the torque variation of a twelve-cylinder engine, we had not analysed the range of stress in each section of the crankshaft. Since he has all the matter at his finger ends, we think it would be worth while applying the same calculations to the new proposed "Condor" shaft. From the deductions, it seems clear that the calculated stress from the torque diagram is not excessively high, but it should be realised that the shaft being flexible and subject to vibration, the stresses may run up to two or three times the amount shewn by the calculations. The second point of doubt is, that the crank, being such a peculiar shape, may have local sections stressed far above that shewn by calculating the shear stress of a plain shaft. Assuming then that the materials are as satisfactory as we can expect them to be, it remains to be proved whether it is the shape of the shaft or the torsional swing which caused the breakage. I cannot see an easy way of proving this except by subjecting the shaft to reverse stresses of some R.R. 235A (500 T) (S.D. 408. 26-4-17) Bm. 2/156/15. | ||