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 The A.T. Speedometer Co. Ltd. discussing the performance of Jaeger speed indicators.
| Identifier | ExFiles\Box 165\2\ img131 | |
| Date | 4th November 1937 | |
| The A.T. SPEEDOMETER CO. Ltd. MAGNETIC SPEEDOMETERS & MOTOR CLOCKS REVOLUTION INDICATORS FOR MOTOR CARS, MOTOR BOATS AND ENGINES, MILEAGE RECORDERS, ETC. DIRECTORS W. Henderson-Cleland. A.{Mr Adams} Gordon Smith. H.{Arthur M. Hanbury - Head Complaints} R.{Sir Henry Royce} Buckland. YOUR REF. Rm{William Robotham - Chief Engineer}/RC{R. Childs}/./3/JH. PLEASE QUOTE OUR REF. HRB/MS. CHRONOS WORKS, NORTH CIRCULAR ROAD, LONDON, N.W.2. ALL COMMUNICATIONS TO BE ADDRESSED TO THE COMPANY Telephone: GLADSTONE 1136 (4 lines). Telegrams: Aytespeedo, Phone London. Handwritten: 6051 Messrs. Rolls-Royce Ltd., DERBY. Handwritten: RC{R. Childs} 4th November 1937. Dear Sirs, We beg to acknowledge receipt of your letter of the 2nd inst. under the above reference, regarding the two speed indicators that you refer to. These instruments were sent by us under cover of our letter of the 22nd September addressed for the attention of Mr. Davies. The Jaeger Chronometric Speedometer does, as you indicate, have the characteristic of moving in a series of small jerks; it also has the other characteristic you refer to, in that if a car is very severely braked, it is possible to stop the car before the hand arrives at zero, and in that event the hand will stay in the position it happens to be at when the car becomes stationary, and only goes to zero again when the car starts to move off. This particular instrument we are unable to supply to run at your revs. of 765 per minute, and the only way in which this instrument could be so run would be for us to supply a suitable gear box to take care of the difference. The Jaeger Magnetic Speedometer we were able to design to run at your revs. of 765. This instrument was based on our ordinary design of Jaeger Magnetic speedometer, of which we make several thousands weekly, but it was, of course, specially finished in many ways, in an endeavour to make it reasonably suitable for you to test. - 1 - | ||