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).
Gearbox test investigating issues with the first speed gear.
| Identifier | ExFiles\Box 6\4\ 04-page110 | |
| Date | 30th March 1925 | |
| R.R. 407a (30m) (D.R. 175 20-9-24) J.H.D. EXPERIMENTAL REPORT. -2- Expl. No. REF: Hs{Lord Ernest Hives - Chair}4/LG30.3.25. We fitted a gearbox with the standard 1st. speed gears to the car and ran that on the dynamometer, and we found with no springs fitted to the plungers, the 1st. speed worked out persistently whilst the oil was thick and cold but as soon as the gearbox reached its normal temperature, there was no sign of the gears moving. Our intention was, that if we could get the 1st. speed to work out consistently, we could confirm on that car that with a very slight taper on the bore, this would make it XXXX stay in. The force which is now causing the gears to work out is very slight compared with when we had the XXXX solid pinions. If we hold the gears in position, there is never any signs of damage being done to the forks, and usually, the light plunger springs which we use are sufficient to keep the gears in. The force which is tending to work the pinions out when we use the torsionally free pinions, is not as much as we have proved exists on the standard 40/50. We consider if we cannot find a means of definitely overcoming this, that it would be a practical scheme to increase the strength of the plunger spring holding in the 1st. speed gear. The 1st. speed gear on the 4-speed box is one which would seldom be used - the car could always be started off at the second speed so that the stiffer plunger spring need not cause any inconvenience. We have found it frequently happen that the gears will work out when the oil is thick but will not do so when the oil becomes warm. Hs.{Lord Ernest Hives - Chair} | ||