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).
Feasibility and potential development of a torsion bar suspension system, referencing Citroen and Packard models.
| Identifier | ExFiles\Box 128\1\ scan0229 | |
| Date | 7th April 1936 | |
| -2- Torsion bar system. If it were not for the American information available of various other systems, we should favour the torsion bar system. The advantage of using the torsion bars to transfer part of frame torque to the rear end of the bars, appears to be important. Citroens have shown that this system can be built into a compact unit. We therefore think we should experiment with a torsion bar system. Unfortunately there is no car fitted with a torsion bar system which gives the required degree of comfort. We must therefore be prepared to spend considerable time developing such a system, which may even then be inferior to the Packard system. Referring to E.2/HP.7.4.36. The tests we have made on the Citroen car show that increased flexibility would be necessary before this car would be really useful to us. We have been told in France that torsion bar failures with the early models were the cause of the Citroen financial crisis. The friction from shock absorbers have caused a lot of trouble both in France and on the few cars in this country, owing to their exposure to the weather. Hydraulic front dampers are now fitted. The Citroen in France has now become reliable and is a very popular type of car. We do not know of any other manufacturer of a torsion bar suspension whose experience would be useful to us. With regard to the triangular levers being at right angles to the longitudinal axis of the car instead of the apex inclined slightly forward as on the Cadillac and Phantom III, it should be remembered that the Packard triangles slightly face the rear of the car. We should imagine therefore that the danger of trouble due to the triangle being straight is small. We suggest that either a 7 seater Citroen price £345, or a complete front suspension unit, £68, should be purchased. As this Citroen has a similar track to that of the Bentley we should be able to attach the Citroen front unit to our present stiff frame Bentley. New torsion bars to give the desired load of rating, together with a pair of our hydraulic dampers, would be necessary. Hs{Lord Ernest Hives - Chair}/Les.{Ivan A. Leslie} | ||