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).
Steering nut efficiency, self-centering, and gear ratios for the Silver Ghost and New Phantom models.
| Identifier | ExFiles\Box 178\1\ img130 | |
| Date | 13th July 1926 guessed | |
| - 31 - (2) That the nut has the highest efficiency attainable when it leaves the works. If this is not so, no self-centering will be obtained with the standard wheel castor and the car cannot be passed off. Previously with the 14° 20' helix angle, self-centering could be obtained with a nut of moderate efficiency, in consequence the steering freedom frequently increased in service and conjointly the shocks on the steering wheel. Now, before the car leaves the Works, the final tester knows precisely the maximum shocks the customer is likely to experience. Attached is a sketch of the method of measuring the efficiency of the R-R steering nut. It is quite useless fitting a nut into a steering box unless it has an efficiency approaching that given in the tables when tested on the rig. If the nut and worm do not shew an even bedding, the steering will be heavy and will not self-centre. (c) Over-all gear ratio. The Silver Ghost Steering was arranged so that 1 1/4 complete turns of the steering wheel were required from full lock to full lock. 'V' series New PhantomCodename for PHANTOM I were equipped with a slightly lower gear ratio, 1 3/4 turns covering the whole steering range. The complaints levelled at the original New PhantomCodename for PHANTOM I were:- (1) That it was not sufficiently light. (2) That it transmitted too many road shocks. In consequence of this, the .720 lead nut was adopted which gives 2 1/4 turns of the steering wheel from full lock to full contd. | ||