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).
The elimination of radio interference caused by wheel static on cars fitted with a radio.
| Identifier | ExFiles\Box 63\2\ scan0250 | |
| Date | 28th July 1936 | |
| To E.{Mr Elliott - Chief Engineer} To SG.{Arthur F. Sidgreaves - MD} To Wor.{Arthur Wormald - General Works Manager} To By.{R.W. Bailey - Chief Engineer} To Cx.{Major Len W. Cox - Advertising Manager} To Mx.{John H Maddocks - Chief Proving Officer} To Hd.{Mr Hayward/Mr Huddy} To Er. Car Radio 86153. Hs{Lord Ernest Hives - Chair}/Wst.2/JH. 28.7.36. Elimination of interference due to wheel static on cars fitted with Radio. A number of complaints have been received of static electricity generating on the brake drums causing interference with the reception on radio sets fitted to our cars. The earthing through the ball bearings is insufficient to short circuit the effects produced, and it is necessary to provide some additional more conductive earthing device. We have fitted to Experimental car 21-G-IV, an earthing device which consists of a small carbon brush let into an adaptor fitted to the nut of the wheel hub, and bearing upon a bronze spring secured to a small cap riveted to the wheel grease cap and this is now running satisfactorily. Unfortunately wheel static does not occur on every car, and owing to the fact that we have not had any trouble on 21-G-IV, we have been unable to determine the exact effect this earthing device produces. It is interesting to note however that an exactly similar device is used on the latest American cars, particularly the Buick, to eliminate wheel static, and we feel that such a device should be fitted to the front wheel caps on all our cars as soon as possible. On the Buick cars they use a flat spiral spring, bearing against a bronze graphite alloy button, and we feel this would be better from the point of view of wear and electrical conductivity than the bronze spring with the ordinary carbon brush used in our Experimental scheme. Thursday 17 | ||