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).
Specifications for 'SAFEGUARD' Brake Lining, including pressure limits and friction coefficients.
Identifier | ExFiles\Box 141\3\ scan0144 | |
Date | 14th February 1933 guessed | |
"SAFEGUARD" Brake Lining can be used with pressures normal to the rubbing surface up to 100 lbs/sq.in. without distortion, although it is not recommended to work beyond 80 lbs/sq.in. The following table has been calculated assuming an average co-efficient of friction of .4 when working against a cast iron drum, and an absorption of work of 1 H.P. per square inch of rubbing surface. Speed in ft/min. Pressure in lbs/sq.in. 500 165.0 1000 82.5 1500 55.0 2000 41.3 2500 33.0 3000 27.5 3500 23.6 4000 20.6 When working with lower speeds the rate of dissipating work will decrease as there is a limit set to the pressure that can be used. Similarly at high speeds, providing arrangements are made for cooling, greater figures than 1 H.P./sq.in. can be allowed. The co-efficient of friction .4 refers only to dry conditions. If the rubbing surface is immersed in water this should be taken as .28. Similarly if the rubbing surface is in oil the co-efficient of friction = .03 - .1 according to the lubricating properties of the oil. | ||