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).
Bump tests detailing fractures in Woodhead road springs.
| Identifier | ExFiles\Box 180\M3\M3.4\ img035 | |
| Date | 9th September 1924 | |
| R.R. 493A (40 H) (SL 42 12-7-23). J.H., D.{John DeLooze - Company Secretary} ORIGINAL EXPERIMENTAL REPORT. Expl. No. 2628 REF: Hs{Lord Ernest Hives - Chair}1/L020.9.24. To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. BJ. ✓ c. to RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} ✓ c. to DA.{Bernard Day - Chassis Design} BY.{R.W. Bailey - Chief Engineer} ✓ c. to Wor.{Arthur Wormald - General Works Manager} V ✓ BUMP TESTS ON ROAD SPRINGS. X9410 X2628 V1331 Below is a list of the 6 fractures we have had on the top plates of the 12 1/4% springs made by Woodheads. An interest-ing point in connection with these springs is that in every instance the fracture has occurred close to the centre bolt. The fractures have taken place under the sheath which holds the spring on to the axle. With the Firths springs, although a percentage of them fractured in this place, the majority of them broke 8" to 12" from the rear eye. Particulars of Woodhead 12 1/4% springs broken on the bumper. Position on chassis. | Load Lbs. | Life hrs. mins. | Position of Fracture. | Thick-ness of top leaf. | Brinnel of Fracture. --- | --- | --- | --- | --- | --- No.1 Near side | 950 | 23 5 | 1.5" to rear | .282" | 375 No.2 " | 950 | 17 42 | 1.5" to front | .282" | 388 No.3 Off side | 1000 | 29 6 | 1.0" to front | .286" | 388 No.4 " | 1000 | 18 5 | 1.5" to front | .293" | 388 No.5 Near side | 950 | 20 1 | 1.5" to rear | .293" | 363 No.6 Off side | 1000 | 20 58 | 1.5" to front | .300" | 363 Fractures measured to front or rear of centre bolt. Below is a comparison of the brinnel hardness and thickness of Firths and Woodhead springs. It will be seen that on the average the Woodhead has a lower brinnel. contd :- | ||