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 North & Sons, Ltd. regarding the testing and calibration of a Watford Revolution Indicator.
| Identifier | ExFiles\Box 165\4\ img222 | |
| Date | 14th August 1933 | |
| x6005 SPEEDOMETERS The BRITISH MADE Watford & MAGNETOS. NORTH & SONS, LTD. H.{Arthur M. Hanbury - Head Complaints} TANSLEY WITT, F.C.A. RECEIVER & MANAGER. WHIPPENDELL ROAD, WATFORD. TELEPHONES: LONDON 1346 GERRARD WORKS: WATFORD, 4422 (2 Lines) TELEGRAMS: AEROMAGS WATFORD CONTRACTORS TO THE ADMIRALTY, WAR OFFICE, AIR MINISTRY, CROWN AGENTS FOR THE COLONIES, INDIA OFFICE. Ref. CHK/JG. Your ref. Hs{Lord Ernest Hives - Chair}/Wst.5/KT. 14th August, 1933. WST Messrs. Rolls Royce Ltd., Derby. Dear Sirs, re Watford Revolution Indicator. We thank you for your letter of the 10th instant and regret to note that you consider the combined Revolution Indicator and Clock recently returned to you to be slower than it was when received by us. We can only conclude that the different results are obtained by different methods of testing, as the instrument, before being returned to you, was very carefully checked in view of the request made on your order No. R.3869 and we found, by repeated tests, that the instrument was reading 4500 when the actual number of turns of the Flexible Shaft is 1099. You order specifies 1100 turns when this speed is indicated and we do not think it possible to calibrate an instrument more closely to your requirements. In checking the calibration we used a counter in conjunction with a chronograph. One push starts both counter and chronograph, and the second push stops both, so that the possibility of any error in the stopping and starting of the two is eliminated. The counter is operated by direct gearing and has a hand travelling over a large scale so that the reading of one revolution is quite easy, and there is no /over | ||