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).
Cost analysis and manufacturing review of the Phantom III crankcase.
| Identifier | ExFiles\Box 132\3\ scan0070 | |
| Date | 9th August 1937 | |
| Hs.{Lord Ernest Hives - Chair} from Rm.{William Robotham - Chief Engineer} c. to By.{R.W. Bailey - Chief Engineer} c. to RHC.{R. H. Coverley - Production Engineer} [Handwritten]: 316 also 1260 Rm.{William Robotham - Chief Engineer}1/AP.9.8.37 P.III. CRANKCASE. The other day you mentioned to me that we could not afford to go on making the P.III. crankcase and block as it is. We have been investigating to see what can be done to improve matters. You told us that the Alum. we use on car castings is what is for disposal from aero castings and is worth £40. per ton. The finished block on P.III. weighs 135 lbs. Add 20% for wastage and the raw material cost for this item appears to be £3. We know quite a high percentage of finished castings have been scrapped but so far can obtain no information that indicates that this is due to design. We have no information as to what wants altering, the Foundry do not seem to be able to tell us of any difficulties. We obtained some figures from Leylands relative to the cost of large alum. castings, which we attach. Assuming that our casting is 50% more difficult than theirs, then we might expect to get c.45 lbs of casting per man/hour. The rate per hour in the Foundry seems to be 1.72/-/min. We do not see why the overheads should be more than 200%. Since the rough casting weighs 185 lbs. the cost for casting would appear to be £7. 10. 0. This gives a total computed basic cost of this piece in the rough as £10. 10. 0. exclusive of scrap. Considering that this is easily the largest piece on a £1800 chassis we do not feel that it is at all extravagant. It certainly appears to us that it would be difficult to design anything that is fundamentally a great deal cheaper without at least a 100% increase in weight. We cannot see that the factory cost figure as supplied by Rb.{R. Bowen} is reasonable. Rm.{William Robotham - Chief Engineer} | ||