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).
Car's road performance, detailing steering, suspension, weight, and engine characteristics.
| Identifier | WestWitteringFiles\L\Jan1924-March1924\ Scan116 | |
| Date | 1st February 1924 | |
| B.R. 403A (40 H) (SL 42 12-7-23). J.H., D.{John DeLooze - Company Secretary} EXPERIMENTAL REPORT. Expl. No. 9680 REF: Hat/LGM 2.24. -3- The steering is RAC-1. This car is fitted with radius rods as the material for the front springs and radius rods is not available. The front springs on this car are 25% stiffer than std. There is 1/4" of packing under the rubber buffers for the front springs. We have fitted a specially short change speed lever in order to suit the body of this car PERFORMANCE OF THE CAR ON THE ROAD. We have taken a certain amount of trouble in order to calibrate the speedometer on this car. We calibrated the miles per hr. apart from the mileometer. On the test we were able to do, the speedometer was correct to 2 or 3%. The weight of the car complete with spares, tools, two spare wheels, full of petrol, water and oil, no passengers is - Front 1 ton. 3 cwts. (2576 lbs.) Rear 1 ton. 3 cwts. (2576 lbs.) On our best roads round Derby we were able to obtain the maximum speed of 75 m.p.h., an average taken running each way on a piece of road. At 1,000 engine revs. the car speed is 28.8 m.p.h. so that at 75 m.p.h. the engine speed is 2600 revs. approximately. The engine is fitted with torque reaction dampers. The engine is free from torque reaction vibrations. There is a period of noise which comes on about 23 m.p.h. which may be caused by the undershield or scuttle. The exhaust is more noisy than the standard 40/50, both with the cutout open and the cut-out closed. The carburetter is more noisy. The acceleration is very good. This engine has a similar vibration on retard as the original one. There is a bad period at 40 to 42 m.p.h. it is there when running with the throttle shut or coasting with very little throttle opening. It is not there if the engine is switched off and the throttle is wide open. This vibration causes a noise in the coupling between the engine and gearbox. We suggest that the period might be due to the flexibility of this engine coupling. The minimum dia. of the shaft is 1.1". As we have the same vibration on the first car we propose removing (on there) the servo brake drum to see if it has any affect | ||