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).
Torsion test results for a 20 HP crankshaft, from forging to the finished shaft.
| Identifier | ExFiles\Box 6\1\ 01-page101 | |
| 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 | 1.540 | - | - | 2.000 | | | | LENGTH | 1.550 | - | 1.610 | - | - | - | - | 1.525 | | | No. 4 | DIA | 2.200 | - | - | 2.030 | - | - | - | 2.000 | | | | LENGTH | 1.500 | - | 1.550 | - | - | - | - | 1.800 | | | No. 7 | DIA | 2.200 | - | - | 2.030 | - | - | - | 2.000 | | | | LENGTH | 1.725 | - | - | - | - | - | - | 2.000 | | | Nos 2, 3, 5 & 6 | DIA | 2.375 (F) | 2.200 | - | 2.030 | - | - | - | 2.000 | | | | 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 1 & 12 | 1.015 | 1.015 | .805 | - | - | .795 | - | .790 | | | | " " 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 | 4.18 | 2.46 | 2.33 | 2.00 | 1.463 | 1.365 | 1.270 | | | | CALC. STIFFNESS OF ONE WEB LBS INS/RAD x 10⁶ | 3.765 (APPROX VALUES ONLY) | 3.39 | 2.39 | 2.272 | 2.205 | 1.607 | 1.577 | 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 | - | 1.900 | 1.720 | 0.130 | 0.330 | 0.537 | 0.098 | 0.095 | | | | CALC LOSS OF STIFFNESS PER WEB (EACH OP) x 10⁶ | - | 0.375 | 1.000 | 0.118 | 0.067 | 0.598 | 0.030 | 0.117 | | | | RATIO: CALC. LOSS / ACTUAL LOSS | - | .197 | .582 | .900 | .203 | 1.110 | .306 | 1.23 | | ||