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 5° and 20° spirals for pinion engagement, proposing a modification for chassis 9-EX.
| Identifier | WestWitteringFiles\Q\2-July1927-September1927\ 13 | |
| Date | 8th July 1927 | |
| Contd. -4- EFC/T8.7.27. With the observations hole provided it is possible to place the relation of the pinion on the spiral to the wheel in such a manner as to produce an artificial jam, i.e. the application of the teazer current would then have no effect, the juxta-position of the teeth being as in diagram :- This action normal to spiral. This was very readily possible in the 5º case but, though not impossible, it was found to be much more difficult in the 20º case. From these tests it would appear that the 20º spiral is superior to the 5º, and that it would be more satisfactory on a car with the actuator box operated switch making contact at early engagement. For this reason we are proposing to have this arrangement fitted to chassis 9-EX which is at present fitted with a 34º 52' spiral with pinion operated switch. The degree of noisiness is not readily judged from the rig tests. † including push of actuator box. EFC. | ||