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 from the National Physical Laboratory discussing the design and result consistency of an impact testing machine.
| Identifier | ExFiles\Box 76\2\ scan0006 | |
| Date | 9th August 1917 | |
| X.3128 - 1929 [Map of Teddington showing route to N.P.L.] NEAREST ROUTE:- ADELAIDE ROAD, PARK ROAD, PARK LANE. ALL COMMUNICATIONS TO BE ADDRESSED TO THE DIRECTOR. TELEGRAMS:- "PHYSICS, TEDDINGTON." TELEPHONE:- 728 KINGSTON POST. STATION & POST OFFICE, TEDDINGTON. The National Physical Laboratory. Engineering Department, Teddington, Middlesex. REF. En.1/TES August 9th. 1917. E.{Mr Elliott - Chief Engineer} F.{Mr Friese} Clark, Esq., The Rolls-Royce Company, Ltd., DERBY. Dear Sir, I regret the delay in answering your letter of July 23rd., reference, E.F.C.4/T23717, which is due to my absence from the Laboratory on leave. The original impact testing machine, which we designed and made here some years ago, for the purpose of a research on repeated impact, has never given any trouble on the score of difficulty of repeating the results of tests, but unfortunately, as regards this particular feature, in deciding to undertake the manufacture of machines working on the same principle, The Cambridge Scientific Instrument Co., entirely re-designed the bed plate and the mechanical details of the testing machine, with the result apparently, from information which has reached me from other sources than your own, that the rigidity of the bed in which the machine is mounted, has no appreciable effect on the number of blows required for practice. I think, however, that the method you propose of bolting each machine to a solid cast iron plate 3" thick, ought to be sufficient to obtain reasonably consistent results. It must be remembered that in all classes of fatigue testing, slight differences in the uniformity of the material, produce far greater effects then in ordinary tensile tests. Yours faithfully, [Signature] Superintendent. | ||