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).
Testing policy and the standardization of a short connecting rod for the 40/50 HP chassis.
| Identifier | ExFiles\Box 35\2\ scan 076 | |
| Date | 31th May 1919 | |
| To C.J. from Bn.{W.O. Bentley / Mr Barrington} C.c. H.H. C. EFC. X.3429 Bn{W.O. Bentley / Mr Barrington}2/P31.5.19. RE STANDARDIZATION SHEET - X.3400D - SHORT CONNECTING ROD FOR 40/50 HP. CHASSIS. With reference to the attached standardization sheet and your remark as follows :- "Bn.{W.O. Bentley / Mr Barrington} 20 hours. In pre-war days surely we ran a new part more than 20 hours. We used to insist on 10,000 miles or equivalent dynamometer work. CJ." The policy of running new parts for 10,000 miles is still good as a general policy, but I think it must be interpreted reasonably, and some flexibility must be allowed in both directions. For example, 10,000 miles of ordinary road testing will not show up faults in some parts, and conversely it is quite unnecessary to run certain other parts for so long. As regards the short connecting rod which it is proposed to adopt, and which is in the shops for manufacture. This is based on the original design but has been improved as regards the change of section of the material in accordance with the experience we have gained during the war, and mechanically it is quite certain that there is no greater risk of failure than with the old rod. The tests that have been carried out were solely for the purpose of ascertaining whether the engine ran satisfactorily with them without regard to reliability of the connecting rod, and the alteration was effected for the purpose of overcoming certain difficulties experienced with the use of aluminium pistons. The tests necessary to prove this rody for standardization were not to ascertain whether the rod would fail or not, but were to enable expert judgement Contd. | ||