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).
Bumping tests comparing 12 1/4% Firths road springs with Woodheads springs.
| Identifier | ExFiles\Box 119\2\ scan0215 | |
| Date | 29th October 1924 | |
| R.R. 495A (20H) (D.A. 652 20-8-24) J.H.D. EXPERIMENTAL REPORT. 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 EY. Wor.{Arthur Wormald - General Works Manager} Expl. No. V1331 REF: Hs{Lord Ernest Hives - Chair}3/LG29.10.24. FIRTHS ROAD SPRINGS. V1331 We attach herewith a report of bumping test on the 12 1/4% Firths springs of the latest design. It will be seen that the average life of the top leaf of these springs is less than Woodheads, although in one case, the front top leaf has lasted longer than any of the Woodheads. We have had a visit from two of Messrs. Firths representatives and have pointed out to them the inconsistency of the results of their springs and that we do not consider it is worth while doing extensive road tests until we could shew better results on the bumping rig. The discussion brought up the fact that our drawing for the front springs shewed the top leaf to have .25" camber when free. Firths have worked to this, but in the case of Woodheads, they have not worked to the specification - the camber on the top leaf being approximately 1". (This can be confirmed by the sample spring you have at W.W.) Messrs. Firths spring Designer considered that more camber in the top leaf, as carried out by Woodheads, is desirable. It was agreed that Messrs. Firths should supply us with further sets of springs for test in which we give the same latitude as regards the camber of the top plate and thickness as we do to Messrs. Woodhead. Hs.{Lord Ernest Hives - Chair} | ||