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 the Cadillac Motor Car Company detailing the specifications and use of a bumper test rig.
| Identifier | ExFiles\Box 170\3\ img001 | |
| Date | 8th January 1936 | |
| oy Exptl. Dept. Hs{Lord Ernest Hives - Chair}/Les.2/KW. 8th January, 1936. M.{Mr Moon / Mr Moore} Olley, Esq., The Cadillac Motor Car Company, Detroit, Michigan, U.S.A. Dear Oy. Grylls tells me you would like a little information re Bumper Test Rigs. Our rig is as follows - (1) 2 x 4 ft. diameter drums. (2) Each having one cam diametrically opposite the other. (3) Drum revs. 105 r.p.m. Until recently we have used cams 2" high, J-2210. Now we are using cams 3" high, J-2211, in order to accelerate failures. When using 2" cams, 100 hrs. is generally considered to be a safe life. For radiator mountings 10 hours is often equivalent to 10,000 miles. A frame failure from a shock damper bracket which occurred during 10,000 miles in France did not occur on the bumper until 180 hours. As the chassis which we bump generally have no wings or bodies, we have to add weight to the chassis in order to get the normal spring deflection. The position of the added weights greatly affects failures in the frame structure. Should recommend that you bump a complete car. | ||