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).
Test report on a new lightened A.T. speedometer and revolution indicator for Bentley chassis.
| Identifier | ExFiles\Box 59\2\ Scan292 | |
| Date | 15th December 1933 | |
| 86051 Sg.{Arthur F. Sidgreaves - MD} From Hs{Lord Ernest Hives - Chair}/Wst. c. to Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} c. to By.{R.W. Bailey - Chief Engineer} c. to Hn.{F. C. Honeyman - Retail orders} c. to EV.{Ivan Evernden - coachwork} Hs{Lord Ernest Hives - Chair}/Wst.4/MA.15.12.33. NEW LIGHTENED TYPE A.T. SPEEDOMETER AND REVOLUTION INDICATOR FOR BENTLEY CHASSIS. We have now received for test the first samples of the new type A.T. instruments designed to meet our requirements in respect to :- (a) Reduced weight. (b) Reduced temperature error. (c) Reduced price. The instruments have very neat dials with much larger trip and total mileage recorder figures. Also by redesigning the case the diameter of the instruments has been reduced by .250" without interfering with the dial diameter. The clock winder and the speedometer trip setter have both been placed in new positions so that there will be no possibility of the driver fouling them with his knee or hands. The weight of these instruments is 1 lb. 10 ozs. for the rev-clock and 1 lb. 13 ozs. for the speedometer. This is a reduction of 1 lb. 4 ozs. for the rev clock and 1 lb. 2 ozs. the speedometer as compared with standard. Bench tests shew also that the temperature error has been reduced and we give below a table shewing the percentage error with rise of temperature :- Speedometer. Scale Reading. R.P.M. of drive. Temperature °C. Percentage error. 60 771 19 - .20% 60 768 30 - 1.5% 60 743 65 2.0% | ||