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).
Breakages during a 100-hour bumper test on a 20 HP chassis.
| Identifier | ExFiles\Box 119\2\ scan0303 | |
| Date | 4th January 1928 | |
| To Hs{Lord Ernest Hives - Chair}/ 44268 4-1-28 Bumper Test on 20 H.P. Chassis fitted with the Latest Improved Geometry Steering to N. Sch 2401. We have concluded 100 hours running on the above chassis under the usual bumber conditions viz: front-tyre pressure 60 lbs/□", bumper drum revs: 105 R.P.M, height of bumper cams = 1.50". The following breakages took place. | Part Broken | Time run | |---------------------------------------------------|----------| | S.S tube spring F.54759. | 31hr 35. | | S.S springs F.54759. | 22hr 50. | | S.S ,, F.54759. | 20hr 30 | | S.S springs F.54789. | 25hr 5 | | c/s rear engine bearer bolt. | 21hr 20 | | ,, ,, ,, ,, | 60hr 25 | | Radiator stay rod. | 48h.25. | | Radiator suspension springs | 74h 55. | | c/s flange of 2nd cross member from rear cracked | 74h 55. | | c/s rear engine bearer bolt. | | | Front engine suspension bracket. | 81-45 | | c/s flange of 2nd cross member from rear cracked | 97-40 | F53587 Road Springs (650 lbs) | Part Broken | Time run | |-----------------------------|----------| | N.S. Spring. (old spring) | 1hr 30. | | O.S. Spring. | 16hr 5. | | N.S. Spring. | 19hrs 50.| | O.S. Spring. | 19hrs 10.| | N.S. Spring. | 23hr 50. | | O.S. Spring. | 19hrs 10 | | N.S. Spring. | 11hr 45 | | N.S. Spring. | 9hr 20 | | O.S. Spring. | 22hr 50 | | N.S. Spring. | 20hr 45. | | O.S. Spring. | 20hr 25. | AHedley | ||