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).
Letter to a supplier regarding endurance tests and requested modifications for flexible road springs.
| Identifier | ExFiles\Box 106\1\ scan0255 | |
| Date | 21th May 1931 | |
| Handwritten: X 5410 X.4429. X.5410. Expl. Dept. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}8/KT. 21st. May, 1931. Messrs Thos. Firth & Sons, Ltd., Norfolk Works, Sheffield. Dear Sirs, FLEXIBLE ROAD SPRINGS. We have now completed a series of tests on the 25 HP. road springs of which you supplied us to Piece No. F.5520. You will recollect that the thickness of the top plate of these springs was reduced to .220" in order to keep the stress within reasonable limits. At the same time although the camber of the complete spring is 4.5", the camber of the main leaf is only 3". In spite of these precautions the stress in this plate is very high, the more so as it has to stand a certain amount of braking torque. Nevertheless these springs have shewn a remarkably good life on our endurance test. In order that we may utilise a thicker top leaf we would ask you to consider building up a pair of front springs for our 25 HP. car having top plates .300" thick and these plates being of such reduced camber, the stress is slightly lower than those we have been recently testing. We appreciate that having done this it will be necessary for you to increase the number of subsidiary leaves which will make the spring heavier and we should be glad if you would let us have a drawing shewing what proposals you would make, so that we can submit to Sir Henry Royce your recommendations on the subject. Yours faithfully, For Rolls-Royce Ltd. | ||