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).
Feasibility of using alternative rear springs on a Continental Phantom III, detailing required modifications and negative side-effects.
| Identifier | ExFiles\Box 92\6\ scan0079 | |
| Date | 4th January 1937 | |
| To BY.{R.W. Bailey - Chief Engineer} Copy to Dr. Hives, Rm{William Robotham - Chief Engineer}/Les.{Ivan A. Leslie} E/Ev.{Ivan Evernden - coachwork}2/MN.4.1.37. Front Spring Bracket For Rear Springs, Continental Phantom III. We have been requested in Rm{William Robotham - Chief Engineer}/Les.22/AP.17.12.36, to provide a means for using up Phantom III rear road springs F.84852 and F.84654 to the value of 474 lbs. and already in existence on Phantom III Continental cars. As the standard Phantom III rear road spring has a roll offset front eye and the Phantom II springs in question have a central forged eye it is necessary to drop the centre of the front spring bracket in order that the spring may clear the bottom welding flange of the frame. We show a suitable bracket on LeO.5450. This entails two new forgings and two rather expensive dies, and we presume that it has been computed that it is worth going to this expense to use up the Phantom III springs in question. We cannot see the value of perpetuating the use of these Phantom II springs on the Phantom III. It is stated that the Phantom II Continental springs weigh 48 lbs. less and cost 20s/6d less than the Phantom III, but this can only be because they are springs with .8" less initial deflection than the normal springs and contain less steel. On examining the details of the two springs Phantom II and Phantom III we can see no other reason and can only conclude that if we made a Continental spring for Phantom III which would suit the existing spring fixings the weight and cost should be comparable with that for the Continental Phantom III springs. We are in the course of investigating the effect of changing from an offset eye to a central eye on the brake geometry and propeller shaft pumping, but we have progressed sufficiently far to say that both the brake geometry and the running of the propeller shaft will be made a fair amount worse. The foot brake pumping will be increased so that the brakes will come off by 3/4" of rope movement at the axle on bump, and go on by a slightly greater amount on full rebound. We shall be sending you a layout of the geometry of the brake ropes and propeller shaft with this centralised spring in a few days time. It will be noticed that spring F.84852 has a central rear eye and spring F.84654 has an offset rear eye. The | ||