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 brake lining tests and squeal characteristics.
| Identifier | ExFiles\Box 141\2\ scan0267 | |
| Date | 13th March 1939 | |
| 1180 All Communications to be addressed to the Company. FERODO LIMITED TELEPHONE: 250 CHAPEL-EN-LE-FRITH TELEGRAMS: FRICTION, PHONE, CHAPEL-EN-LE-FRITH. CODES: WESTERN UNION FIVE LETTER EDITION, BENTLEY'S COMPLETE & 2ND PHRASE, MARCONI INTERNATIONAL, LIEBER'S CODE, LIEBER'S LATEST CODE, A.B.C. 5TH & 6TH EDITIONS. FERODO REGD. TRADE MARK. BRAKE & CLUTCH LININGS CHAPEL-EN-LE-FRITH, STOCKPORT, ENGLAND. Depots- LONDON 222, TOTTENHAM COURT RD W. 1. ABERDEEN 26, GUILD STREET. BELFAST 8, 10 & 12, MONTGOMERY ST BIRMINGHAM 198, CORPORATION ST BRISTOL 118, VICTORIA STREET. CARDIFF 60, CHARLES ST DUBLIN 120, UPPER ABBEY ST GLASGOW 70, WATERLOO ST LEEDS 25, HUNSLET RD LIVERPOOL 1-3, BERRY STREET. MANCHESTER 16, JACKSON'S ROW, DEANSGATE. NEWCASTLE-ON-TYNE 2A, ELDON PLACE, BARRAS BRIDGE. YOUR REF. Rm{William Robotham - Chief Engineer}/JBD.{John B. Dixon - Fuel Systems}15/JH. OUR REF. WES/PW. 13th March, 1939 Messrs. Rolls-Royce Ltd., Experimental Department, Derby. Dear Sirs, We thank you for your letter of the 10th instant, and the Ferodo BZ and RU brake linings to your Part Nos. GB.3760 and GB.4685 respectively have been immediately put in hand. With regard to the rig for squeal characteristic tests, one of the new cast iron plates which you supplied was immediately fitted. We then ran into difficulties in the final grinding operation, and while we at first thought this was in some way connected with the new plate, we eventually found that the test machine clutch at the other end of the electric motor was responsible for the difficulty in truing the plate. We have now eliminated this trouble and apparently arrived at the following stage. All the lining samples in our possession, including Thermoid but excluding VG.90, give a convex curve on the paper and in addition, and in accordance with the theory underlying this rig, they also audibly squeal. VG.90 gives an almost straight line record when cold and is silent, but very slight temperature rise produces a slightly convex curve and audible confirmation of this curve. We cannot help feeling that the present weight and elasticity of the rig more or less matches up in proportion to the size of lining samples and the energy dissipated with that obtaining in a vehicle brake gear which is prone to squeal, and that this results in the rig squealing as well as the fact that we get a characteristic squeal curve. We suggest that it would be useful to have a further set of Thermoid samples, and also that you may care to spend a day here observing the behaviour of this rig when the plate is taken up to higher temperatures. We have not yet heated up the plate as we should prefer you to see any possible change in conditions which may occur when this is carried out. Yours faithfully, FERODO LIMITED. W.E.Shilton Technical Department. | ||