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 A.T. Speedometer Co. enquiring about drive revolution specifications and noting discrepancies.
| Identifier | ExFiles\Box 59\2\ Scan093 | |
| Date | 11th December 1930 | |
| X4308 c. By c. Mailing. EFC4/AD. 11th December, 1930. The A.T. Speedometer Co. Chronos Works, North Circular Rd. London, N.W.2. Dear Sirs, Drive Revolutions per indicated mile of A.T. Speedometers. We are anxious to know the complete range of possible figures of the drive revolutions per indicated mile which you can arrange in the A.T. speedometers between the limits of say, 680 to 820. We know, for instance, that you can give 720, 730, 765, 785 and 800. At the moment, what we are particularly anxious to know is the possibilities between 785 and 800. Another point in this connection is that we have noted that the figure for the revolutions per mile stamped on instruments has not invariably been in agreement with the actual number of revolutions per mile of the instrument itself. To cite a case of this, a particular instrument C.83, 800, 14/52 when tested for the revolutions per mile shewed the figure 792, another marked 740 was actually 742.6 and ought, therefore, to have been marked 743 though the error is comparatively small. | ||