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).
Steering geometry, road shocks, and wheel types.
| Identifier | ExFiles\Box 72\3\ scan0300 | |
| Date | 6th March 1924 | |
| 49430 To HS.{Lord Ernest Hives - Chair} & DA{Bernard Day - Chassis Design} FROM R.{Sir Henry Royce} SECRET R2/M6.3.24. c.c. to Wor.{Arthur Wormald - General Works Manager} RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} BY.{R.W. Bailey - Chief Engineer} PN.{Mr Northey} E.A.C. STEERING. X.9420 X.9430 We must get along with producing something. We cannot now change the parts in progress to alter the angle of the pivots much, and neither should we know what to do, that would make a material change. We are better than Hispano in dimensions according to the figures received from DA.{Bernard Day - Chassis Design} It is difficult for me to see how the extra inclination can very much increase the road shocks to the steering. I am also quite of the opinion that we must keep near centre point steering. The only wheels we can recommend are those which give us this, namely, disc and wire wheels. Disc might be silent enough for the front and might be altered for the back. Many people are using disc wheels for important work. The best big passenger 'buses running past here use them. After the first few weeks I have not again seen those with 4-wheel brakes, perhaps because they were difficult to steer, or in some other way not a success, or unnecessary. It would seem that we must repeat the experiments and make sure how the shocks are produced. You seem to indicate that it is not the sides of the potholes, but the upward pressure, before the centre. Steel wheels may be heavier and compress the tyres more on a shock. If it is upward pressure then the steel wheels further out should be worse for everything except my original point if the remaining shocks (with perfect geometry and centre-point steering) came from oblique pressure in front and behind the pivots - (side of pothole, etc.) Your new point is that the worst shocks are from vertical forces in front of a point directly under the pivots :- [Diagram showing a wheel with labels 'Shock point.' and 'Pivot axis.'] I think this wants proving, and I would like RG.{Mr Rowledge} and DA{Bernard Day - Chassis Design}'s correction of my errors if I am writing rubbish. In conclusion we must make the best of what we are doing, because we really do not know what else to do under the conditions (we are not worse than others who are thought good) and to do this - (a) we must try different cushioning in the longitudinal rod. I think slightly set up springs with ample clearance, and not too great a rating is the best thing to try. (b) The lowest speed of steering so as to get less vigorous shocks. contd:- | ||