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).
The calibration results and issues for a Bensport speedometer.
| Identifier | ExFiles\Box 59\2\ Scan207 | |
| Date | 28th June 1933 | |
| 86051. To By.{R.W. Bailey - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/Wst. c. to E.{Mr Elliott - Chief Engineer} c. to Wor.{Arthur Wormald - General Works Manager} Hs{Lord Ernest Hives - Chair}/Wst.3/KT.28.6.33. BENSPORT SPEEDOMETER CALIBRATIONS. We have now completed bench and road tests on the Bensport chassis with India tyres in order to determine the exact speedometer revs. per mile calibration. We have definitely confirmed that these figures, with India tyres at 35 lbs/sq.in. pressure are :- For 10/41 axle - 797 " 11/41 " - 724 " 11/43 " - 759 These figures should be increased by 10 revs per mile when Goodyear tyres are used. With regard to the mounting plate we have found that the steel one instructed by the D.O. seriously affects the magnetic operation of the instruments making them both read low. We have immediately put in hand three of these plates in Phosphor Bronze and will report immediately we have had an opportunity of trying the same. The scale of these instruments should be in the case of the rev. counter dead correct to 2% fast, and the speedometer 5% fast at 60 m.p.h. up to 6% fast at 100 m.p.h. Hs{Lord Ernest Hives - Chair}/Wst. | ||