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 detailing preliminary test results on two brake drum liners and their coefficients of expansion.
| Identifier | ExFiles\Box 141\1\ scan0082 | |
| Date | 30th November 1935 | |
| FERODO LIMITED TELEPHONE: 19 CHAPEL-EN-LE-FRITH (4 LINES) TELEGRAMS: FRICTION, PHONE, CHAPEL-EN-LE-FRITH. FERODO BRAKE & CLUTCH LININGS CHAPEL-EN-LE-FRITH, STOCKPORT, ENGLAND. 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. 30th November 1935 YOUR REF. OUR REF. JNL/IS. Depots:- LONDON 22, TENHAM COURT RD W.1. ABERDEEN 26, GUILD STREET. BELFAST 8,10 & 12, MONTGOMERY ST BIRMINGHAM 198, CORPORATION ST BRIGHTON 84, QUEEN'S ROAD. BRISTOL 118, VICTORIA STREET. CARDIFF 39, CHARLES ST DUBLIN 120, UPPER ABBEY ST GLASGOW 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 A.{Mr Adams} F.{Mr Friese} Martindale Esq., Messrs Rolls-Royce Ltd., Derby. Dear Mr Martindale, We have now completed some preliminary tests on the two brake drum liners you left here at the beginning of this week. One ring was marked "NMC / 42545S2." This ring has a coefficient of linear expansion per degree centigrade of .0000172. At a normal braking temperature of 550°F, therefore, its internal diameter will be increased by .056". The second ring was unmarked and it had a slightly lower coefficient of expansion, namely, .0000161, so that at 550°F.{Mr Friese}, the internal diameter will be increased by .0525". I think these rings, being regarded as sufficiently alike, represent the limit that can be obtained in high expansion steels, the figure for normal steels being .000011 per 1°C. On the same reckoning, however, ordinary aluminium has a coefficient of expansion of .000022, and it would be necessary, or desirable, to produce an aluminium alloy with this figure reduced to about .000018. This, I believe, has been done, but by whom I cannot at the moment tell you. We are retaining the liners here pending your further instructions, and shall be pleased to hear from you in due course. In the matter of the rivets, we are pleased to be able to inform you that we shall be despatching these to you within the next week, and there will be no difficulty in obtaining quantities in production, if, and when, you are satisfied that they will perform satisfactorily. Kind regards, Yours very truly, [Signature] Chief Chemist, | ||