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).
Table of torsion test results for a 20 HP crankshaft from forging to finished shaft.
| Identifier | ExFiles\Box 31\2\ Scan075 | |
| Date | 7th December 1927 | |
| 20 H.P. CRANKSHAFT – TORSION TESTS. FORGING TO FINISHED SHAFT OPERATION, 15, 19, 21, 22, 31, 33A, 39A, FINISHED SHAFT MAIN-BEARINGS No 1, DIA, 2.200, -, -, 2.030, -, -, -, 2.000 No 1, LENGTH, 1.550, -, 1.610, -, 1.540, -, -, 1.525 No. 4, DIA, 2.200, -, -, 2.030, -, -, -, 2.000 No. 4, LENGTH, 1.500, -, 1.550, -, -, -, -, - No. 7, DIA, 2.200, -, -, 2.030, -, -, -, 2.000 No. 7, LENGTH, 1.725, -, -, -, -, -, -, 1.800 Nos 2,3,5&6, DIA, 2.375 (F), 2.200, -, 2.030, -, -, -, 2.000 Nos 2,3,5&6, LENGTH, .650 (F), 1.020, 1.070, -, -, -, -, 1.050 CRANK-PINS INNER DIAMETER, 0, -, -, -, 1.250, -, -, - OUTER ", 1.900 (F), -, 1.625, -, -, 1.530, -, 1.500 INNER ", 0, -, -, -, -, -, .750, - LENGTH, 1.100 (F), -, 1.480, -, -, 1.490, -, 1.500 NOSE OUTER DIAMETER, 1.450, -, -, -, 1.420, -, -, 1.400 INNER ", 0, -, -, -, .625, -, -, - LENGTH, 4.300, -, -, -, 2.520, -, -, 2.500 WEBS DEPTH OPS. 6, 7 & 12, 1.015, -, .805, -, -, .795, -, .790 DEPTH OP 2,3,4,5,8,9,10,11., 1.200 (F), 1.015, .805, -, -, .795, -, .790 WIDTH, 2.550 (F), -, -, -, -, 2.200, -, - TEST RESULTS MEASURED STIFFNESS OF WHOLE SHAFT. LBS FT/RAD, 53,000, 41,400, 27,200, 25,600, 22,800, 17,400, 16,400, 15,280 (2 BEARINGS) .'. STIFFNESS ONE WEB WILL BE :- LBS INS/RAD, x 10⁶ 6.08, x 10⁶ 4.18, x 10⁶ 2.46, x 10⁶ 2.33, x 10⁶ 2.00, x 10⁶ 1.465, x 10⁶ 1.365, x 10⁶ 1.270 CALC: STIFFNESS OF ONE WEB LBS INS/RAD, x 10⁶ 3.765 (APPROX VALUES ONLY), x 10⁶ 3.39, x 10⁶ 2.39, x 10⁶ 2.272, x 10⁶ 2.205, x 10⁶ 1.607, x 10⁶ 1.577, x 10⁶ 1.46 (7 BEARINGS) RATIO: CALC: STIFFNESS / TEST STIFFNESS, .620, .811, .971, .9725, 1.103, 1.098, 1.155, 1.15 RATIO: TEST STIFFNESS / FINISHED STIFFNESS, 3.47, 2.71, 1.78, 1.675, 1.49, 1.14, 1.07, 1.0 MEASURED LOSS OF STIFFNESS PER WEB (EACH OP), x 10⁶, x 10⁶ 1.900, x 10⁶ 1.720, x 10⁶ 0.130, x 10⁶ 0.330, x 10⁶ 0.537, x 10⁶ 0.098, x 10⁶ 0.095 CALC LOSS OF STIFFNESS PER WEB (EACH OP), x 10⁶, x 10⁶ 0.375, x 10⁶ 1.000, x 10⁶ 0.118, x 10⁶ 0.067, x 10⁶ 0.596, x 10⁶ 0.030, x 10⁶ 0.117 RATIO: CALC: LOSS / ACTUAL LOSS, .197, .582, .900, .203, 1.110, .306, .123 | ||