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).
Air Ministry's empirical formula for crankshaft stiffness and comparing calculated versus test results.
Identifier | ExFiles\Box 65\4\ scan0208 | |
Date | 24th November 1927 | |
RG{Mr Rowledge} BY X8010 Hs{Lord Ernest Hives - Chair}/Tsnl/LG24.11.27. AIR MINISTRY EMPIRICAL FORMULA FOR CRANKSHAFT STIFFNESS. X5010 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 sub- tracted. The car crankshafts given in the table were cal{Mr Calvert}- culated 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}/S.S.Tresilian. | ||