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).
Alteration of gear ratios for A.T. Speedometers to achieve accurate readings.
| Identifier | ExFiles\Box 59\2\ Scan133 | |
| Date | 27th March 1931 | |
| By.{R.W. Bailey - Chief Engineer} from EFC. c. PN.{Mr Northey} C. c. Wor.{Arthur Wormald - General Works Manager} Hs.{Lord Ernest Hives - Chair} X6051. EFC4/AD27.3.31. X.6051. A.T. SPEEDOMETERS. Further to our EFC1/AD24.3.31 we have now received an answer from the A.T. Co. to our enquiry, referred to on page 3 of that memo, as to whether the figure 816 is a possible figure for the revolutions per counter mile of these instruments. They state that the nearest figures they can attain are either 810 or 825, these applying both to total and trip portions of the instrument. In these circumstances we would like to ask you what possibilities there are in alteration of the gear ratio to render either 810 or 825 a suitable figure for these modified instruments. For 810 instruments our drive gear ratio should work out at 1.336 and for 825 instruments 1.361. To get the full benefit of our present proposal it does appear worth while to attempt to get an accurate mutual adjustment between instrument and our own drive gear ratio. EFC. | ||