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).
Design memorandum discussing modifications to the gearbox, back axle, and brake systems.
| Identifier | ExFiles\Box 178\3\ img185 | |
| Date | 30th November 1936 | |
| (2) We are arranging for considerably more foot pressure than in the case of the Alfa Romeo, somewhere between 35/40 lbs. on the pedal. It will be safer from unintentional releasing, and we think we shall be very pleased with the extra clearance that it will enable this (7/8 multi plate) clutch to have, the Alfa Romeo appearing to be short in this respect. GEARBOX. In my last memo. I suggested considering leaving room for a servo, but we find that the servo cannot be in the usual place as it is too high relative to the floorline, and would have to be placed below the shaft in a compartment by itself. We do not however propose to fit the servo in the first instance, so in any case we are in a position that we can slide two large wheels on the 3rd. motion shaft instead of the two small pinions and layshaft. We know from experience that the larger the wheels relative to the splines the less liable the wheels are to creep along the shaft. In fact, we had no trouble with creeping gears until we were induced, by fitting the servo, to slide the two small pinions. This also gives us a slight advantage as regards the reverse pinion, but we shall still need the double stroke of this reverse pinion, though it will now be a plain double width gear and so be less costly. We have schemed some mechanism which does not look too complicated so that the change speed lever will only move the usual distance for the reverse. The tendency for such a gear to come out we think is extremely small, and the shaft in this instance can be short and well supported. BACK AXLE. Another item we have looked into since my return home is the back axle for this model. It has at present been arranged to have this hypoid, but I think that owing to the small size, and the load that we are likely to put through it, we may find the scrubbing of the teeth more than the surfaces will bear, so we think it will be wise to have at least a design ready for a spiral ordinary bevel (non-hypoid). Whether the works will put this in hand or not I will leave to their judgment. BRAKES. With reference to the brakes it is understood that these will not be of the 6 brake pattern, but of the 4 brake, as used by the Bentley Co. It will have double connections to the rear brakes so that in case of cable failure these brakes will still operate. A very great advantage in this 4 brake system is that the shoes on the rear axle can be so much wider without inconvenience. D.A. has carefully gone into the multiplication, and the weight of the car, and if we have an equally strong man to drive it, we think there should be no difficulty in making this and the Peregrine without servo | ||