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 Pratt & Manley detailing the test results for a Composite Steel Brake Drum.
| Identifier | ExFiles\Box 120\3\ scan0043 | |
| Date | 15th June 1933 | |
| X456 J.{Mr Johnson W.M.} H.{Arthur M. Hanbury - Head Complaints} PRATT. GILBERT MANLEY. PRATT & MANLEY, CONSULTING ENGINEERS MANUFACTURERS x AGENTS TELEPHONE: MIDLAND 4130. YOUR REF................ OUR REF...WEB......... 23, GUILDHALL BUILDINGS, NAVIGATION STREET, BIRMINGHAM. Jun. 15th. 1933. Messrs Rolls Royce Ltd., Derby. Dear Sirs, For the attention of Mr Hives. Further to our previous correspondence on the subject of the Composite Steel Brake Drum, we are now in a position to communicate the results of tests, which we trust will be of interest to you. By the courtesy of Messrs. Ferodo Ltd., severe tests have been carried out in their laboratory, and in these the temperature raised to 600° F.{Mr Friese} on 25 occasions. Rigidity was not affected even with 500 lbs shoe pressure at 750° F.{Mr Friese}, with a brake force at the drum radius of 1150 lbs, this force being applied 2000 times at the rate of 132 applications per hour, the drum remaining true and the torque readings remarkably steady. In Messrs. Ferodo's report the opinion is expressed that after a certain amount of rubbing the surface probably became work hardened, in which condition it would resist any tendency to abrasion, also that compared with cast iron or alloy cast iron more consistent braking can be looked for with steel. We have now over 100 of these drums on test on various makes of cars all giving satisfaction, and we have been instructed to supply several sets for the forthcoming Alpine Trials by users of the experimental drums. One maker of a very high class fast car has already standardised them. Trusting that you will give further consideration to this matter and that we shall have the pleasure of your instructions to supply an experimental set. Yours faithfully, For Pratt & Manley, W.B. Baylis | ||