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).
Necessity and cost of modifying the 20 HP model to address high-speed wobbles when using medium-pressure tyres.
| Identifier | ExFiles\Box 55\3\ Scan199 | |
| Date | 14th June 1926 | |
| To Hs. {Lord Ernest Hives - Chair} from BJ. Hydraulic Dampers. With reference to Hs {Lord Ernest Hives - Chair} 2/LG11/6/26, it is of course difficult for me to gauge how far any alteration in design is absolutely essential and also how far that alteration has come about owing to an endeavour on the part of the technical officials to overcome complaints which they have heard from Sales Officials, which might possibly have given them an exaggerated idea of the necessity of adopting perhaps a very expensive modification. For this reason, before adopting such a modification, it is necessary for me to make quite sure that it is not based on the possibility of a misunderstanding. I am not quite clear at present in regard to high speed wobbles on the 20. Your memorandum says that, when medium pressure tyres are fitted to the 20, it will be in the same position as the 40/50 HP with present tyres. Do I understand that you have satisfied yourself that the 20 HP has serious high speed wobbles when fitted with medium pressure tyres? Have these tests been made: (a) With our present shock absorbers. (b) Without any shock absorbers, and (c) When the hydraulic dampers are fitted, has this entirely eliminated the high speed wobble? You will realise that, so far as Sales officials are concerned, they have had no experience of high speed wobble on the 20 HP under any conditions. For that reason they would be interested to experience high speed wobbles on the 20 HP. You will appreciate that the difference between the cost and selling price of the 20 HP is so extremely limited that the addition of £11.4.2 per chassis is sufficient to make it necessary for us to consider raising the selling price, which is most undesirable in view of the very competitive nature of the 20 HP model on the market. It is for this reason we are studying extremely carefully the matter of such an enormous jump in the cost. I rely on you to give me all possible information and assistance to help us to come to a satisfactory decision and to assure ourselves that it is not based on a misunderstanding between the Sales and the Technical Departments. BJ. | ||