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).
Potential modifications and weight reductions for vehicle axles, wheels, and engine.
| Identifier | WestWitteringFiles\Q\July1927-September1927\ Scan130 | |
| Date | 15th September 1927 guessed | |
| (2) The Front road springs were thought to weigh about 33 lbs. for a 1000 lb. spring. They would probably have 2.1 camber, which when added to the inch negative camber, produces 3.1 camber as the running deflection. (3) FRONT AXLE. Regarding the front axle, this will have the parallel torque control via the shock dampers as already arranged, and there is little that can be done to this except reducing the road wheel hubs by fitting the new standard wire wheels, which do not protrude so far, and will also reduce the weight of the hubs. In passing, balloon tyres will be used as are already standard on our production Phantom, the advantage of these being that they are lighter, and that they will save the chassis and coachwork from some of the road shocks. In connection with the wheel hubs we ask you to look into the French wheels known as R.A.F. Rudge-Whitworth, and also to get a similar short wire wheel from the Dunlop people to suit the artillery wheel hubs which we have already shortened. (4) BACK AXLE. Regarding the back axle, I have always believed that this could be considerably lightened. We know now that the large brake drums need not have fins, because of the extra front wheel brakes, and would naturally be fitted with our anti-squeak bands as are at present standard on the front brake drums, and on the 20HP. It will be noticed that it is not necessary to have much elasticity on the surrounding spring, so that it can be wound from the very thickest wire practicable. DA{Bernard Day - Chassis Design}/HDY.{William Hardy} is looking over the drawings to see what other lightening can be effected to the axle and torque tube. In the meantime we understand you are getting a duralumin forging instead of steel for the brake shoe anchorage. There are also the brake camshafts which are at present very heavy. It will be understood that most of this lightening will be done by drilling and turning, and will be arranged to keep the spares interchangeable. In connection with the bearings it is thought that the recently introduced double New Departure might be used to save some weight of bearings. (5) ENGINE. Regarding the engine, and the introduction of the anti-detonating head (for which the credit must be given to Mr.Elliott) we have found that a compression ratio of 5 to 1 is now free from detonations. This compression ratio will not be used as a general standard, but only on the sports cars. | ||