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 performance of their brake linings regarding water effects and squealing.
| Identifier | ExFiles\Box 141\3\ scan0234 | |
| Date | 19th December 1933 | |
| X719 All Communications to be addressed to the Company. FERODO LIMITED 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, BENTLEY'S 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. December 19th 1933 YOUR REF. Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}9/KT. OUR REF. Secretary/WAC. Depots:- LONDON 222, TOTTENHAM COURT RD. W.1. ABERDEEN 26, GUILD STREET. BELFAST 8,10 & 12, MONTGOMERY ST.{Capt. P. R. Strong} BIRMINGHAM 202, CORPORATION ST.{Capt. P. R. Strong} BRIGHTON 84, QUEEN'S ROAD. BRISTOL 19, PARK STREET. CARDIFF 39, CHARLES ST.{Capt. P. R. Strong} DUBLIN 120, UPPER ABBEY ST.{Capt. P. R. Strong} GLASGOW 70, WATERLOO ST.{Capt. P. R. Strong} LEEDS 25, HUNSLET RD. LIVERPOOL 1-3, BERRY STREET. MANCHESTER 32, CATHEDRAL ST.{Capt. P. R. Strong} NEWCASTLE-ON-TYNE WORSWICK CHAMBERS, 10, WORSWICK ST.{Capt. P. R. Strong} OFF PILGRIM ST.{Capt. P. R. Strong} Messrs. Rolls-Royce Limited, Experimental Department, Derby. GRYLLS For the attention of Mr. Grylls. Dear Sirs, The writer regrets that, owing to a slight indisposition, he was unable to reply immediately to your letter of the 14th instant. Referring to the effect of water in brakes, it is quite true that a temporary loss of brake power is experienced irrespective of the type of lining, but certain linings are not so seriously affected as others, and in this respect we should place Ferodo Bonded Asbestos Die-pressed well in front of M.R. and Ferobestos in order of relative effectiveness and recovery. Ferodo M.Z. in our opinion, has similar characteristics to Ferodo Bonded Asbestos and we suggest that, if any substantial difference was obtained when you were testing, it was due in all probability to the quantity of water present in each case. Even very small differences in the quantity will make a marked difference both in the loss of power and in the time of recovery, but there is not the slightest doubt that Ferodo Bonded Asbestos has a distinct advantage over the majority of linings and over M.R. in particular after cars have been washed and water has entered the drum or drums. You are, of course, aware that lubricants in any form (water, perhaps, is the most powerful anti-friction agent of them all) are exaggerated in the case of Servo brake shoes, hence when shoes of this type are fitted it has been found necessary to provide a more adequate seal than is afforded by the ordinary single guard plate - for instance, the arrangement adopted on the Humber SNIPE drums, as shown in sketch enclosed. However, this device will not exclude water, for instance, when a drum is partially immersed in a water splash or ford, but it does act remarkably well when cars are washed. Referring to squealing with M.R. this lining is more frictionally efficient than Ferodo Bonded Asbestos and,since squealing is associated with the coefficient of friction,it follows that drums would have a greater tendency to vibrate with the first named lining than with the other. Generally, we do not consider that | ||