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, thickness, and life of Woodhead and Firth leaf springs.
| Identifier | Morton\M3.4\ img036 | |
| Date | 20th September 1924 | |
| R.R. 493A (40 H) (SL 42 12-7-23). J.H., D.{John DeLooze - Company Secretary} -2- Expl. No. REF:Hol/LG20.9.24 EXPERIMENTAL REPORT. Comparison of hardness of top leaves. Table Data: Column 1: Woodhead 12 1/4% Thickness of top leaf. | Brinnel. .282" | 375 .292" | 388 .286" | 388 .292" | 363 .293" | 388 .300" | 363 Aver: hrs. mins. life 21 29 Column 2: Firth 25% Thickness of Top leaf. | Brinnel. .292" | 375 .305" | 401 .307 | 401 .308" | 401 .305" | 401 .310" | 415 hrs. mins. 18 17 Column 3: Firth 12 1/4% Thickness of Top leaf. | Brinnel. .305" | 388 .308" | 401 .308" | 401 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} | ||