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).
The merits and costs of thick leaf springs versus thin leaf springs and shock absorbers for the 40/50 model.
| Identifier | ExFiles\Box 54\3\ Scan089 | |
| Date | 26th October 1922 | |
| BJ. PN.{Mr Northey} WOR.{Arthur Wormald - General Works Manager} BY.{R.W. Bailey - Chief Engineer} HS.{Lord Ernest Hives - Chair} EP.{G. Eric Platford - Chief Quality Engineer} CJ. FROM R.{Sir Henry Royce} X2628 RL/M26.10.22. 40/50 - THICK LEAF SPRINGS X.2628. Referring to BJ17/H20.10.22., this seems to be a question of money. The 238 springs we understand will all be wanted and that the cost of these is approximately £6 each, assuming also that the cost to replace them with thin leaf springs will also be £6 each, so that it is £12 per car. Originally the thick leaf spring was introduced because of the complaints :- (1) Weight of the chassis. (2) Friction of the thin leaf springs needed lubrication. (3) Cost of production. These springs were intended to be fitted with either single acting or progressive type of shock absorber. After running these springs for some time no serious complaints against these-springs their use were forthcoming. Personally, however, I found the cars were insufficiently stable at high speeds on the undulating roads on the Fens. I then renewed my demand for shock dampers. Through a certain amount of half-heartedness these shock dampers were never fitted. After many cars had been constructed with these thick leaf springs it was found in conjunction with the cord tyres that much more damping was needed and since we had not obtained this damping satisfactorily with shock dampers, and cars with thin leaf were found to be superior, I suggested that I should prefer to change the springs to thin leaf springs rather than fit shock dampers. The reason for my preference was that the shock dampers in their joints were much less satisfactory than the thin leaf springs, which had no serious disadvantage over the thick leaf springs. I cannot agree for one moment that the thick leaf spring with a double acting Hartford shock absorber is better than the thin leaf spring with the same fitting, or better than the thin leaf spring alone, and I am sure that the conclusions arrived at that this is the best springing in the world is not necessarily correct. Personally, I would rather have thin leaf springs alone or thin leaf springs with lighter shock dampers, and these latter of the single acting or progressive type. The conclusion is then to my mind that it is merely a question of money. Ought we to consider the £12 seriously considering the price the complete car is costing the customer. Ought we not to fit that which we think will give the greatest satisfaction, especially as at the moment we must do all that it is humanly possible to do to give satisfaction. Regarding the defects of the thick leaf springs they are reported :- contd:- | ||