Letter to Ferodo Limited regarding the trial and supply of servo motor linings for a Bentley.
| Identifier | ExFiles\Box 141\3\ scan0336 | |
| Date | 7th December 1934 | |
| x719 Exptl. Dept. Hs {Lord Ernest Hives - Chair} /FJH. {Fred J. Hardy - Chief Dev. Engineer} 20/KW. 7th December, 1934. Messrs. Ferodo Limited, Chapel-en-le-Frith. Attention - Mr. Longley. Dear Sirs, We have made an experimental alteration to the design of our Bentley servo motor which, we anticipate, will result in a 20% reduction in working temperature. This alteration necessitates having internal splines on the linings as shown on the attached drawing ref. EX.16740. attached. Our Experimental Drawing Office have already sent you an order for some servo linings to the above drawing in RAD.13 material. Will you please send us, in addition, 6 similar linings in VM.30 material, as this has considerably better /u characteristics. Some time ago you sent us for trial some linings in S4947 which contained rubber. When we tried these on our rig we obtained a /u of 0.47 cold; falling to 0.29 at 210° F. {Mr Friese} and rising again to 0.38 at 330°F. {Mr Friese} This is an undesirable characteristic but we fitted a pair to a car mainly to determine whether they squeaked or whether the smell of rubber was noticeable in the car and persisted beyond the "running in" period. When first tried on the car the reports of their behaviour were not encouraging and we dismissed them as being unsuitable. Lately, however, we have had occasion to make good use of the brakes on this car for other purposes and we find that the servo is behaving very well indeed. As the car has now covered 2,000 miles since the linings were fitted, we are wondering at what stage of this running they developed their desirable characteristics and we therefore wish to give them a further trial. | ||
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).