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).
Characteristics and performance of the New Phantom steering system compared to the old one.
| Identifier | ExFiles\Box 67\4\ scan0019 | |
| Date | 3rd March 1926 | |
| X8430 To OY. from Hs.{Lord Ernest Hives - Chair} Hs{Lord Ernest Hives - Chair}9/LG5. 3.26. NEW PHANTOMCodename for PHANTOM I STEERING. When you come on to the New PhantomCodename for PHANTOM I steering with the 720 lead worm, the helix angle is such that unless the nut and worm are very well made, the steering will be irreversible and therefore not self-centering. As long as the steering nut and worm are a good bed, it is reversible as far as self-centering is concerned. Because of the big area of thread in contact, and the fact that we harden the worm and work on a whitemetal nut in an oil bath, we have not been able to measure any appreciable wear after 25,000 miles. We attach a chart which we have prepared for the Works so that they can ensure that the steerings are correct whilst they are being built up. On the old steering, the helix is such that any old bed on the nut and worm would pass. What happened of course was that as the nut bedded down to the worm, the steering got freer and more reversible and therefore more road shocks were felt. We strongly recommend that you get going on the steering early to find out your difficulties. Hs.{Lord Ernest Hives - Chair} | ||