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).
Modifications to wheel arch clearances and revised instructions to coachbuilders.
| Identifier | WestWitteringFiles\T\March1929-December1929\ Scan198 | |
| Date | 4th September 1929 guessed | |
| (2) ORIGINAL. see this should ensure a reasonable margin of safety for normal conditions, but we should not be frightfully agitated if some cars got through without this modification. IMMEDIATE ACTION - REVISED INSTRUCTIONS TO COACHBUILDERS. We would be glad if Derby would modify the wheel arch clearance on the subframe prints, in accordance with this, and issue fresh prints to Sales, and all coachbuilders having subframes already delivered should be circularised concerning the cutting away of the top flange of the subframe. As soon as possible Derby should deliver subframes suitably shaped. THE FUTURE. (1) In a separate memo. we are asking the Exp. Dept. to thoroughly investigate the problem of wheel arch clearances, as apparently the old empirical data of taking the centre of one wheel as the point of pivoting of the axle to determine the wheel arch clearance, which was perfectly satisfactory for cantilever springs, is not applicable to a car having half elliptic springs. (2) The rolling test which was found to provide, and somewhat agree with, the empirical data of (1) does not appear to be in agreement with (1) when both (1) and (2) are applied to a WJ. series car. If the wheel arches were made on WJ. series to permit of a rolling test being made on the body unladen, even though the track is .5" greater, the wheel arch width between the wheel arches would have to be almost 2" less than Phantom. This is incomprehensible. We hope that this makes the matter clear, and that all parties concerned will take the necessary action. DA{Bernard Day - Chassis Design}/EV.{Ivan Evernden - coachwork} | ||