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).
Comparing the hardness and life of spring top leaves from Woodhead and Firth.
| Identifier | ExFiles\Box 180\M3\M3.4\ img036 | |
| Date | 1st September 1924 | |
| R.R. 493A (40 H) (SL 42 12-7-23). J.H., D.{John DeLooze - Company Secretary} -2- Expl. No. REFssl/1020.9.24 EXPERIMENTAL REPORT. Comparison of hardness of top leaves. | Woodhead 12½% | Firth 25% | Firth 12½% | |---|---|---| | Thickness of top leaf. Brinnel. | Thickness of Top leaf. Brinnel. | Thickness of Top leaf. Brinnel. | | .282" 375 | .292" 375 | .308" 388 | | .282" 388 | .305" 401 | .308" 401 | | .286" 388 | .307 401 | .308" 401 | | .292" 363 | .308" 401 | | | .293" 388 | .305" 401 | | | .300" 363 | .310" 415 | | | Aver: life (life is struck through) hrs. mins. 21 29 | hrs. mins. 16 17 | hrs. mins. 15 45 | N.B. The figure given for the thickness of the top leaves are averages, as the actual thickness varies within about .010" from point to point. We attach a chemical analysis of the top plate from 6 of the latest Woodhead springs. We also attach a comparison of the life of front springs classified under different poundages. It will be seen that stiffer springs give longer life. These springs are all Firths 25% stiffer. Hs.{Lord Ernest Hives - Chair} | ||