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).
Technical discussion regarding axle weights, component weights, and their impact on sprung vs. unsprung mass.
| Identifier | ExFiles\Box 12\2\ 02-page022 | |
| Date | 1st November 1927 | |
| Hs.{Lord Ernest Hives - Chair} from DA.{Bernard Day - Chassis Design} X7350 DAA/M4.11.27. EAC.7. AXLE WEIGHTS. X.8840 X.7350 With reference to Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}2/LG2.11.27., we expect that we shall discuss the whole of this question with R.{Sir Henry Royce} in the course of the next day or two, and shall probably have some further instructions to send you. In the meanwhile we should like to make the following remarks. We do not understand whether the universal joint has been included in the 40/50 weight, as the list speaks only of the sphere and housing. Should not there be added to this, in addition to the universal joint, the brackets brazed to the cross member with the adjustable trunnion ends for carrying the torque sphere, and also the draw bars with their fixings. It appears to us that the weight of 21.9 lbs. for the whole of this gear is rather small. Though the frame side member on EAC.7. is essential to that method of taking the torque we do in fact make use of it to carry the spare wheel at the back, and the luggage grid, both of which are essential components of the chassis, and therefore we think you ought to add to the weight of the Phantom side members the extensions for carrying the spare wheel, etc. There is no reason why the rear springs should weigh any more, and it is evident that there is a considerable drop in the stress. We think that the difference in weight of the rear springs should be ignored except when you are comparing sprung and unsprung weights. The weight of the universal joints presumably is from the Mechanic's joints. As we think you know we intend to reduce these very much in size. DA.{Bernard Day - Chassis Design} | ||