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).
Proposal for a stress-testing apparatus to determine the breaking point of a crankshaft.
| Identifier | ExFiles\Box 42\2\ Scan042 | |
| Date | 28th April 1917 | |
| Contd. -2- E4/G14418. known value, and I fear it would take a long time to rig up the necessary tackle, but one feels sure that this would be well worth the trouble. The following is the description of the simplest apparatus that I can at the moment think of. Take a scrap crankchamber, fit into it a crankshaft with all its bearings in the usual way, placing this crank-chamber down on a suitable base, and with a plate at the annulus end to prevent the crank turning. Fit two cylinders in cells Nos. 5 and 6, and then arrange the crank so that the connecting rod is at an excellent angle in each cylinder for giving a big torque. Arrange for hydraulic pressure (water or oil) to be communicated to the ignition plug holes of the two cylinders passing through a valve which permits of pressure and exhaust alternately, supply water or oil under a controlled pressure to the valve, reciprocate this by means of a crank driven from a neighbouring shaft or electro-motor. With this arrangement a shaft could be subjected to a known stress, and if the operation is performed slowly the extra stress, due to the swing, would be negligible. I should suggest about 40 reversals per minute, which would be 2,400 per hour, and approximately 60,000 per day. At the end of 10,000 reversals the pressure and stresses could be increased until the shaft broke. With this device one could ascertain the value of any change in the proportions of the shaft, webs, pins, radii, rounding of corners, etc. etc. It would also tell us Contd (upside down text at bottom) R.R. 235A (500T) (S.D. 408. 28-4-17.) Box 2/156/13 | ||