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 reliability of Firths springs to Woodheads springs through bumping tests.
| Identifier | ExFiles\Box 119\2\ scan0214 | |
| Date | 27th October 1924 | |
| R.R. 493A (20H) (D.A. 652 20-3-24) J.B.D. EXPERIMENTAL REPORT. Expl. No. H1331 REF Hs{Lord Ernest Hives - Chair}4/LG27.10.24. To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. BJ. c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} c. to BY.{R.W. Bailey - Chief Engineer} Wor.{Arthur Wormald - General Works Manager} c. to Wd.{Mr Wood/Mr Whitehead} BUMPING TESTS WITH FIRTHS SPRINGS 12 1/2% STIFFER - THIN LEAF TYPE. The bumping tests are proving the Firths springs to be less reliable than Woodheads. So far we have broken 3 top leaves - one lasted 13 hrs. 46 mins., the second 22 hrs. 23 mins., the third 11 hrs. 35 mins. Woodheads springs made to a similar design - out of 7 springs tested, the worst spring lasted 17 1/4 hrs., and the best 32 1/2 hrs. The average life of the Woodheads spring is 25 hrs. We will send a further report on Firths springs when tests have gone further. It is however the safest policy at the moment to continue ordering Woodhead springs. Hs.{Lord Ernest Hives - Chair} | ||