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).
Vehicle springing, weight distribution, and shock absorber improvements for Phantom II.
| Identifier | ExFiles\Box 16\4\ Scan222 | |
| Date | 1st December 1930 guessed | |
| (2) Experiments also shewed that if we could get the weight away from the centre of the car and carry it back, over and behind the back axle, the riding would be better, and pitching would be less. This is undoubtedly the case and Phantom 2. permits of better springing than ever we could get with Phantom 1. or Silver Ghost. In Derby there has been a struggle of opinions between flexible, and stiffer springing, which latter was favoured by all the fast drivers on our English roads. There has also been much trouble caused by the body weights not being the same as estimated, that is, often the weights allowed in the springing are much greater than the average load. I believe this has caused more dis-satisfaction than anything, the springing having been sent out suitable for the full estimated body weight, plus full spares, plus full load of passengers, and plus a fair percentage of luggage, whereas the average riding is generally done by a driver with often only one passenger sitting far back, right over the rear axle, on the springs which are suitable for 6 or 7 people and luggage. In conclusion, I am much happier with the present (Phantom 2.) axle control and lighter axle, and the better weight distribution that the rear springing gives, but I am sure it is necessary for you to do all that is possible to keep the conditions nearly ideal, which means that the passengers should not be further back than is absolutely necessary, that there should be the minimum weight possible on the front axle, and centrally between the axles, and the weight of spare wheels, tools, battery, fuel, etc, behind the back axle. There is no doubt that we have considerably improved the weight distribution by taking away the weight of the spherical control, much of the gearbox, the starter motor, and the rear springs from the centre of the car. We know you must generally have glass between the driver and rear seats; you need not however have the battery and spare wheels central or forward, but as results shew all the efforts we have made in weight distribution can be easily spoilt from your point of view by having the springs too stiff. As regards the shock dampers I believe the rear ones are those that give the trouble, but the present ones can be much improved by the spring loaded (external) connection, and by shortening the lever to 10" which is only possible if the axle is restrained so that its motion does not exceed 10" instead of the present 15". The instructions will be sent to you for this. We are making some important modifications to our designs. In our improvements we are taking up any slack between the piston and its lever automatically, (Lovejoy's do not do this) and are using a single valve for both directions, and other features which we hope will put us ahead of everything we know. | ||