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).
Improvements to the Phantom's suspension system, comparing it to the Silver Ghost.
| Identifier | WestWitteringFiles\O\January1926-March1926\ Scan78 | |
| Date | 25th February 1926 | |
| TO BY.{R.W. Bailey - Chief Engineer}) FROM R.{Sir Henry Royce} HS.{Lord Ernest Hives - Chair}) (Le CanadelHenry Royce's French residence.) ORIGINAL R2/M25.2.26. C. to CJ. BJ. WCH. RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} PHANTOM SUSPENSION. X8410 X4565 X8520 X235 Mr. Johnson remarks that the Phantom rides worse than the Silver Ghost. Fortunately there is no difference in back spring design, and as far as comfort of riding in back seats is concerned, I feel certain it has nothing to do with front springs. I heard casually at WW. that cars were leaving Derby with rear springs that were too stiff for the body weight, owing to wrong estimates by coachbuilders, or something to that effect. I suggested we turn out chassis in such a way that we more often had to strengthen the back springs than to nearly always change them for more flexible ones. (1) So that we must first see that springs are as flexible as bumping on the rubbers allow. (They will occasionally bump anyway if going fast on bad roads.) (2) Next we must see that shock dampers are not too tight. For slow speeds about London no shock dampers are needed on the back. If at all tight they almost stop the road spring working at all, but on these rough roads at any speed over 20 MPH. they improve the riding and prevent too much motion, which might give sea-sickness. We are hoping for more good without harm from the hydraulic ones, which are urgent. (3) Also it is of the utmost importance to keep the tyres at as low pressure as practically possible. Nothing can replace the flexibility of the tyres (except better roads), and in all my experience, for a given road tyres are first. Consequently we must be prepared to fit low pressure tyres, or run with ordinary tyres at low pressure. The car Mr. Johnson remarked upon should have been examined to see that (1) and (2) were suitable to our best standards. Then we should demonstrate the advantage of changing the tyres to the semi-balloon type at say 30 lbs., and also reducing the ordinary type to 45 lbs. Repeatedly I find cars (occasionally including London Sales) with too stiff back springs, and too highly pumped tyres. The two together are hideous at slow speeds. On really good roads the matter is simple, but at low speeds on bad roads perfection of riding is impossible. This latter is what I experience here: it is minimised as above. We designers can do little more than is done. E.A.C.1. & 7. may be slightly better. The hydraulic damper may be slightly better, but bad management of rear road spring stiffness & highly pumped tyres will ruin all, and spoil (fy) anything that can be done. | ||