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).
Testing A.T. speedometers and the problems caused by running them in reverse.
| Identifier | ExFiles\Box 59\2\ Scan095 | |
| Date | 15th December 1930 | |
| x4308 RECEIVED 17 DEC 1930 To: Mr. Hives (crossed out) c-c: S-H.{Arthur M. Hanbury - Head Complaints}/Mr.Hough (crossed out) c Roy{Sir Henry Royce}/Aden (crossed out) c Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux} ✓ from Mx.{John H Maddocks - Chief Proving Officer} Mx{John H Maddocks - Chief Proving Officer}/LA{L. A. Archer}9/T15.12.30 re Phantom II and 20/25HP Chassis - A.T. Speedometers. Roy{Sir Henry Royce}/JT2/HP16.11.30 and Mx{John H Maddocks - Chief Proving Officer}/LA{L. A. Archer}3/T18.11.30. Since the above correspondence the representative from the A.T.Speedometer Co.Ltd, has been to the Works, and we have demonstrated to him that running speedometers in reverse does harm these instruments - he was convinced. He has since had sent along to us for test a special speedometer fitted with a ratchet to the trip gear. We are returning this speedometer to Roy.{Sir Henry Royce} herewith. We have run this instrument on our rig for 3000 miles 1305 of which was done on reverse. We consider the principle of this instrument to be quite good and should go a long way towards overcoming the troubles with the trip gear which have been experienced and which we believe are mainly due to the trip gear drive not being reversible. We still feel that some better provision should be made for thrust on the vertical drive for the trip gear, and also on the instrument which A.T. have sent for us to test, we think the gearing of the worm and worm wheel could be fitted up more carefully. It will be noticed on this instrument that the worm wheel is quite a long way off the centre of the worm, this means that only a bare 50% of the tooth is taking the load. Also both the shafts driving the mileage recorder and the trip gear run rather badly out of truth. Mx{John H Maddocks - Chief Proving Officer}/LA{L. A. Archer} [signature] | ||