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).
Investigation into a Phantom III steering failure by analyzing the broken components.
| Identifier | ExFiles\Box 153\1\ scan0282 | |
| Date | 25th April 1939 | |
| 1300 BY.1/G.25.4.39. F.T.H PHANTOM III. STEERING FAILURE. Sg.{Arthur F. Sidgreaves - MD}8/E.21.4.39. is to say the least of it somewhat hasty and premature, you should at least have suspended judgment until we had discussed the matter. My memos are a perfectly impartial attempt to interpret the facts as displayed by the broken pieces, which represent the only real evidence; these broken parts by the form of the fracture indicate clearly that the failure was caused by a single impact, the form and markings of the failure indicate this without a shadow of doubt. Secondly, the roller race at the end of the rocker shaft was indented by the rollers. Thirdly, the follower roller which was dismantled for the first time at the Works had the rollers driven so far into the hardened race that the race was cracked where each roller was situated at the time of the impact. I arranged immediately I saw the broken parts to examine two or three rocker shafts which had been twisted about ten degrees by known accidents, none of these exhibiting cracks. I then gave the Laboratory the worst example of these, and told them to make a rig and twist off the rocker shaft end in a similar manner to the broken shaft by fitting a pendulum lever and imposing a load on the end of the lever - it took 3000 lbs. on the lever to shear the rocker shaft. This has now been done, and the fracture is identical with that on the shaft from Paris. Having satisfied myself, and incidentally the technical people at the Works, that the shaft had not been partially broken through by a previous accidental impact, I then endeavoured to show how it was possible for a blow of the magnitude required to break the shaft could have occurred at the time of the accident. In all this I fail to see how I was either "excusing" or "explaining away" the actual failure, for years I have had to view and discuss accidents, and as a result of many years experience I know beyond all question that the only way to get at the facts is to let the broken pieces tell one the story. | ||