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).
The bump test results for Woodheads 12¼% road springs, detailing plate failures and performance.
| Identifier | Morton\M3.4\ img027 | |
| Date | 11th September 1924 | |
| To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to E.J. [crossed out] c. to A.G.E. [tick] c. to H.I. [crossed out] c. to W.A.R. [tick] c. to Capt. Harvey [tick] ORIGINAL Hs{Lord Ernest Hives - Chair}4/LG11.9.24. +9410 +4628 ROAD SPRINGS. Woodheads 12¼% springs. We are running on the bump test, Woodheads 12¼% springs. The first springs which were available were those having the top plate .285" thick. This is the plate which Woodheads themselves recommend. The results so far are that one front spring has run for 23 hrs. the top plate then failed near the centre sheath. The other front spring ran for 22 hrs. after which time the bottom plate broke. This was replaced, it then ran for a total of 27 hrs., and the 2nd. and 3rd. plates broke. These are being replaced as the top plate is still intact. The average for these two springs is considerably higher than we obtained with the 12¼% Firths springs on the bump rig. The failures of the top plates which occurred in France are in a similar position on the plate as the average of those which failed on the bump rig, so therefore it would appear that the front brakes have little if anything to do with the failures of the font springs. Hs.{Lord Ernest Hives - Chair} | ||