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 Ferodo Limited discussing the friction and wear characteristics of various brake lining materials.
| Identifier | ExFiles\Box 141\1\ scan0225 | |
| Date | 29th December 1936 | |
| FERODO LIMITED All Communications to be addressed to the Company TELEPHONE: 19 CHAPEL-EN-LE-FRITH (4 LINES) TELEGRAMS: FRICTION, PHONE, CHAPEL-EN-LE-FRITH. FERODO REGD. TRADE MARK BRAKE & CLUTCH LININGS CODES: WESTERN UNION FIVE LETTER EDITION, BENTLEYS COMPLETE & 2ND PHRASE, MARCONI INTERNATIONAL, LIEBER'S CODE, LIEBER'S LATEST CODE, A.B.C. 5TH & 6TH EDITIONS. CHAPEL-EN-LE-FRITH, VIA STOCKPORT, ENGLAND. Depots:- LONDON 222, TOTTENHAM COURT RD W. 1. ABERDEEN 26, GUILD STREET. BELFAST 8, 10 & 12, MONTGOMERY ST BIRMINGHAM 198, CORPORATION ST BRIGHTON 84, QUEEN'S ROAD. BRISTOL 19, PARK STREET. CARDIFF 39, CHARLES ST DUBLIN 120, UPPER ABBEY ST GLASGOW 70, WATERLOO ST LEEDS 25, HUNSLET RD LIVERPOOL 1-3, BERRY STREET. MANCHESTER 32, CATHEDRAL ST NEWCASTLE-ON-TYNE WORSWICK CHAMBERS. 10, WORSWICK ST OFF PILGRIM ST 29th December, 1936. YOUR REF. Rm{William Robotham - Chief Engineer}/AFM{Anthony F. Martindale}3/R OUR REF. JNL/KM A.{Mr Adams} F.{Mr Friese} Martindale Esq., Messrs. Rolls-Royce Ltd., Derby. Dear Mr. Martindale, I thank you for your letter of the 22nd of December enclosing coefficient of friction diagram of our various materials against R.R. cylinder iron. Answering your questions categorically you ask first the wear resistance figure of VM.20 to compare with the other figures I gave you over the telephone. The figure is slightly lower than MR, ranging from about 420 to 450. Next, with regard to the 12 Bentley sets of linings for complaint cases free from squeal, coupling our experience with your coefficient of friction findings I should have said that S.5805 would be free from squeal, but, bearing in mind the heavy lead content of S.6611, it is probable that the high coefficient of friction of this quality will not be conducive to squeal. I think, perhaps, the best thing is S.6611. Further you ask for samples of VM.30, S.5584 and our material for Bendix brakes for test on your rig. I can easily supply these samples but will point out that the VM.20 that you have already tested is the standard Bendix brake material. I cannot help feeling rather disturbed at the variation in the coefficient of friction that you find, particularly with Ferodo MR, and I am just wondering whether your tests are of adequate duration. We have found it necessary here to run linings continuously for about two hours at fairly high temperatures before they can be regarded as stable and bedded. MR, for instance, certainly has a marked fade until it has been taken up twice or three times to 300°C. For this reason I wonder if you would show me the detailed and individual runs that are summarised on your diagram because we think, granting that initially there is a - continued - | ||