Stress limits and reliability of front wheel brake pull-off springs.
| Identifier | ExFiles\Box 66\5\ scan0099 | |
| Date | 10th February 1927 | |
| X8420.? HS. {Lord Ernest Hives - Chair} G-BY {R.W. Bailey - Chief Engineer} /TWD {T. W. D’Aeith} BY10/H. 10.2.27. [STAMP: RECEIVED FEB 10 1927] FRONT WHEEL BRAKES. - PULL-OFF SPRINGS. Referring to Hs {Lord Ernest Hives - Chair} /Rms/LG.31.1.27. I am very doubtful indeed of putting any springs into service with a stress of as much as 100,000 lbs. on same. Our experience is, as confirmed by the cross steering tube springs, that we cannot really rely on a spring if stressed above 90,000 lbs. we recognise that these springs are stressed as a bending moment, and possibly one could therefore apply a slightly higher stress as against a spring in shear, but even at that I think it means new springs. We figure out that with 9½ lbs at the extreme of the lever, and the lever in the "off" position, the stress is up to 101,000 lbs. When the lever is pulled on, which means a further 50° deflection, it puts a further 14,000 lbs. on, which brings the stress up to roughly 115,000 lbs. and I am certain that we cannot rely on the plain standard carbon steel spring we have bought, standing up to this stress for any prolonged period. BY. {R.W. Bailey - Chief Engineer} [Signature] | ||
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).