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 estimations for a Merlin crankshaft with integral balance weights.
| Identifier | ExFiles\Box 148\2\ scan0217 | |
| Date | 17th June 1939 | |
| To Dy.{F R Danby} From m/swdl.{Len H. Swindell} c. HS.{Lord Ernest Hives - Chair} c. EJS. c. AHC. c. Roy{Sir Henry Royce}/Les.{Ivan A. Leslie} c. DA.{Bernard Day - Chassis Design} c. DA{Bernard Day - Chassis Design}/JHP. c. m/swdl.{Len H. Swindell} MERLIN CRANKSHAFT (Ex.912). The following are estimations of the cost analysis on the above from inside and outside information. (1) The tool cost for forging the crank with integral balance weights is £600 as against £300 for the present type of crank without balance weights. (2) In W.C.A. the crank forging cost with integral balance weights is £5.15.0d. as against £4.5.0d. without the balance weights, or an increase of £1.10.0d. (3) The present loose balance weights, their material and (labour + 200%) cost is approximately £2.15.0d. (4) The increased machining necessary with integral weights as against the crank without loose balance weight is estimated at 10/-d.{John DeLooze - Company Secretary} (labour + 200%). The net reduction, therefore, in making integral weight shaft (factory cost) is - £2.15.0d. - £1.10.0d. - 10/-d.{John DeLooze - Company Secretary} = 15 shillings. In view of an extra £300 tool cost, 400 chassis would have to be made before any saving resulted. The above applies to a machined all over job. | ||