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).
Calculations for the periodicity and frequency of a Lorraine Dietrich crankshaft.
| Identifier | ExFiles\Box 25\3\ Scan255 | |
| Date | 25th April 1927 guessed | |
| PERIODICITY OF LORRAINE DIETRICH CRANKSHAFT. NODE L CRANKSHAFT FAN PULLEY I₁ l₁ I₃ l₂ I₂ FLYWHEEL THE POSITION OF THE NODE IS GIVEN BY l₂ = L[I₁ + ⅓I₃] / [I₂ + I₁ + ⅔I₃] WHERE :- I₁ = .3767 = FLYWHEEL I₂ = .001437 = FAN PULLEY .04322 = INERTIA OF CRANKSHAFT .01058 = " BIG ENDS .00587 = " DUE TO PISTONS. I₃ = .05967 = TOTAL OF SHAFT ASSEMBLY OVERALL STIFFNESS OF SHAFT = C = 28350 lbs ft/RAD. l₂/L = [.3767 + .05967/3] / [.001437 + .3767 + 2x.05967/3] = .39659 / .417917 THE INERTIA OF THE PART OF CRANKSHAFT OF LENGTH l₂ WILL BE = .05967 x .3966/.4179 = .0566. THIS INERTIA IS REPLACED BY ONE THIRD ASSUMED ACTING AT THE FRONT END = ⅓ x .0566 = .01887. TO THIS IS ADDED THE INERTIA OF THE FAN PULLEY. ∴ INERTIA OF FRONT END (EQVT) = .01887 + .001437 = .020307 lbs ft². THE STIFFNESS OF A LENGTH OF SHAFT l₂ WILL BE APPROX. = 28350 x .4179/.3966 = 29900. lbs ft/RAD. ∴ FREQUENCY = 1/(2π)√(29900/.02031) = 193 OSCS/SEC. WITH THREE OSCILLNS OF THE DISTURBING FORCE PER REV. THE SYNCHRONOUS SPEED WOULD BE 193 x 60 / 3 = 3860 R.P.M. THIS IS IN CLOSE AGREEMENT WITH 3800 R.P.M. OBSTD BY EXPT. ARR | ||