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 for road springs comparing different cam settings.
| Identifier | WestWitteringFiles\M\2October1924-December1924\ Scan21 | |
| Date | 1st October 1924 | |
| R.R. 493a (20H) (D.A. 652 20-3-24) J.B.D. EXPERIMENTAL REPORT. Expl. No. REF: HsS/LCS.10.24. XB31 BUMP TESTS ON ROAD SPRINGS. X2628 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} ✓ We have carried out a test on the bumping rig by setting the cams 0º in relation to each other instead of being fixed at 180º, which is the standard position. Running under this condition, we have broken three Woodheads 12½% springs (Woodhead design). (a) Failed after 9 hrs. 43 mins. - top plate fracture, 2" rear of centre bolt. (b) Failed after 10 hrs. 50 mins. - top plate fracture, 15" rear of centre bolt. (c) Failed after 9 hrs. 28 mins. -2" to the rear of centre bolt. With the cam set at 180º similar springs averaged 21½ hrs. The shortest life was approx. 18 hrs. This shews that the springs are breaking in half the time when the cams are set 0º to each other. During this test we measured the maximum deflections of the springs. From the normal, the maximum compression was 1.55" - the maximum re-bound was 3.100". With the cams set at 180º, the maximum compression was 1.93", the maximum rebound was 2.58". The buffer clearance during these tests was 2". Hs.{Lord Ernest Hives - Chair} | ||