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).
Piston fractures, the suspected causes including weak castings and high stresses, and plans for further testing.
| Identifier | ExFiles\Box 82\1\ scan0059 | |
| Date | 26th March 1933 | |
| X4583a Hotel de France Chateauroux Indre 26.3.33. To Hs{Lord Ernest Hives - Chair} From GWH{George W. Hancock - Head Chateauroux} We have received your memo Hs{Lord Ernest Hives - Chair} 3/MJ 23-3-33 and note your remarks re PN{Mr Northey} and the Bensport. I have received a further memo this morning from PN{Mr Northey} requesting the car to meet him Wednesday noon at Calais if the car is in order. We received the Pistons from F.{Mr Friese} Dodd this morning and we are at the moment fitting same. The pistons that are being taken out, have stood very well this last two days the speed having been gradually increased untill we were thrushing them. The copper asbestos joint eliminate detonations that were prevalent previously. In our opinion fractures were caused by castings being used, the material being faulty (weak) The fractures were caused by a too high compression and explosion force, rapid accelerations, and decelerations, sustained high speeds, which deflected the piston at the cross cut just below the bottom ring, finally fatigueing the cast material. We carefully examined all the pistons when we first fitted. N° six, and, there was no sign of any cracks anywhere [Drawing of a piston] This dot caused collapse We have received Rm{William Robotham - Chief Engineer}'s memo re running on Monthlery Track. We will endeavour to carry out the instructions, but to our way of thinking we obtain better results by our usual method of running, going round a track at a continual speed does not put the strain on the working parts as when continually accelerating and decelerating. The X339 plugs will be fitted immediately. GWHancock. G.W.H. | ||