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).
Test drive of a supercharged 4-cylinder Mercedes 'Indianapolis' type car.
| Identifier | ExFiles\Box 22\5\ Scan120 | |
| Date | 1st July 1924 | |
| X407 Hs.{Lord Ernest Hives - Chair} EP{G. Eric Platford - Chief Quality Engineer}14/HS.{Lord Ernest Hives - Chair}7.24. re. Mercedes Car Test. 7th. inst. I called at Messrs. Barkers and was able to have a run on the latest type 4-cylinder Mercedes car "Indianapolis" type, 80/130 m/m, fitted with supercharger scheme. There is nothing very special about the running of this car other than the novelty of the supercharging. The car generally was very noisy and rough, the gears and axle were noisy and the riding was heavy, but generally quite satisfactory for a high speed car, i.e. strong springs well damped. For general running purposes on the road the supercharger did not give any advantage, in fact if brought into action at less than about 1750 engine revs. caused the engine to falter owing to the mixture being distinctly too weak, but if brought into action above these revs. it showed a marked advantage in acceleration and power. This increased power was not very manifest until the engine revs had reached about 2,000 when throwing in the supercharger, which was done by a further movement of the accelerator pedal, gave one a 'kick' in the back by extra acceleration. It certainly showed a noticeable advantage about 2,500 to 3,000 revs, and the higher the engine speed the more effective the supercharger. The engine was able to run at 4,000 revs without the driver feeling really upset, but running under these conditions was very disagreeable, and one cannot conceive the ordinary customer running a car under these conditions in order to take advantage of the supercharger. Unfortunately, the car seemed too high geared, i.e 1,000 engine revs about 30 m.p.h. and the driver was continually using his gears. Front wheel brakes were fitted, but these were mechanically operated by ropes and did not seem particularly good, as for really effective braking the driver had also to use the hand brake. The appeared to be of cast iron type and were very noisy in action. CONTD. | ||