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 conducted on road springs, detailing fracture data for Woodhead springs.
| Identifier | Morton\M3.4\ img035 | |
| Date | 1st 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/L.020.9.24. X9410 X2628 V1331 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} BUMP TESTS ON ROAD SPRINGS. Below is a list of the 6 fractures we have had on the top plates of the 12% springs made by Woodheads. An interesting 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% springs broken on the bumper. Position Load Life Position Thick- Brinnel on Lbs. hrs.mins of ness of of chassis. Fracture. top leaf 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 birnnel hardness and thickness of Firths and Woodhead springs. It will be seen that on the average the Woodhead has a lower brinnel. contd :- | ||