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).
Notes on the method of comparing calculated and test stiffness in crankshafts using the Air Ministry empirical formula.
| Identifier | ExFiles\Box 6\1\ 01-page088 | |
| Date | 24th November 1927 | |
| PG B1 K5010 Hs{Lord Ernest Hives - Chair}/Tan1/LG24.11.27. AIR MINISTRY EMPIRICAL FORMULA FOR CRANKSHAFT STIFFNESS. K5010 The following are a few notes on the method of obtaining a comparison between the calculated and test stiffness in crankshafts. The last column on the right gives the stiffness of one complete crank as shewn in the sketch. The torsional deflection of all six cranks will be six radians for the torque in lbs.ins. given here. To this must be added the deflections that will occur in the nose extension for the spring drive, and also in the extra amount of main bearing journal not included in the formula, which only takes account of one half of a short bearing on each side of the crank. These last two items usually amount to about 20% of the total deflection. To obtain the actual stiffness of one crank therefore from the test on the complete shaft, the reverse procedure has to be followed, and the various deflections subtracted. The car crankshafts given in the table were calculated by Major Carter from data supplied by us, and are: 13 c Standard Phantom. 14 c 20 HP. 15 c Special stiff experimental 20 HP. 16 c 1-G-1 17 c Lorraine Dietrich. Hs{Lord Ernest Hives - Chair}/B.S.Trevilian. | ||