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 to Borg & Beck Co. Ltd. regarding the testing of F.F.1 servo lining material and its unsuitability for use.
| Identifier | ExFiles\Box 141\1\ scan0034 | |
| Date | 1st May 1935 | |
| X3409 Exptl. Dept: 1st May, 1935. Hs{Lord Ernest Hives - Chair}/FJH.{Fred J. Hardy - Chief Dev. Engineer}20/KW. Your Ref: TS/HTB/EA. Messrs. Borg & Beck Co.Ltd., Tachbrook Road, Leamington Spa, Warwickshire. Attention Mr. H.F. Barker. Dear Sirs, Re your letters of the 18th and 29th April. We have not yet carried out any further tests on the Servo Linings in F.F.1 material. We are aware that lining materials generally require a certain amount of "running in" before they attain a stable characteristic. Accordingly, we gave the F.F.1 material a total of 1 1/2 hours running in 15 min. periods, the servo being allowed to cool between the periods of testing. We have no reason to doubt the accuracy of our results, and if the F.F.1 material requires more than 1 1/2 hrs. running in, then it is quite unsuitable for our purpose, as this amount of running in represents at least 1,000 miles of hard driving. In view of the above, we do not think any useful purpose would be served by further extensive testing of the material. We should like to point out that the material of the drum and the rubbing velocity have a considerable effect upon the characteristic /u / temperature curve, and this may account for the discrepancy between our figures and the figures given by your suppliers. Our experience on clutches leads us to believe that the greater the fade of the lining material, the smoother is the operation of the clutch. This is in agreement with our results on F.F.1. material, as it gives a smooth "take up" and high fade. Yours faithfully, FOR ROLLS-ROYCE LIMITED. | ||