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).
Development of a new 6-cylinder car (J.3), the need for improved torsional chassis stiffness, and competition from Bentley.
| Identifier | ExFiles\Box 137\4\ scan0309 | |
| Date | 9th April 1931 | |
| E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} } FROM R.{Sir Henry Royce} HS.{Lord Ernest Hives - Chair} } (At Le CanadelHenry Royce's French residence.) 1634. R1/M9.4.31. X. 5770 X. 634. Copy to sG.{Arthur F. Sidgreaves - MD} wOR.{Arthur Wormald - General Works Manager} ENGINE WORK - CARS DRIFT WILL NOT DO. We must make J.{Mr Johnson W.M.} 3. 6 cyl. because we have the big car 6 cyl. I expect to see MR. Ricardo (who is at St Maxim) on Monday and will ask him about the engine that Bentley is making in the 4 litre size which has the one overhead valve and a single side exhaust and turbulent head. It seems to have wonderful performance and nearly fixed ignition. I will find out if we could use it should we wish. Telegraph me if you and HS.{Lord Ernest Hives - Chair} prefer it to our own. Whatever we do we must not be entirely beaten by Bentley when we bring out J.{Mr Johnson W.M.} 3. I do not believe we can make a really good chassis unless we have engine and gearbox to help torsional stiffness. To my present ideas cross members, tubular, even with thick side members, will not give enough stiffness to get really quiet front and no bonnet troubles, steering and axle steadiness, with powerful shock dampers. Torque arms on engine should be forward - i.e. as present front arms on P.2., kept away from dash, and if four are used the other two as far back as possible, say on gearbox to cross member. Could we test this by making underframe for P. 2.? For many years we have tried for lateral stiffness which seems of less importance, and is usually good enough. Now we must and will have, some great improvement in torsional stiffness. I fear we shall not get the satisfaction that is needed by Sales for all kinds of bodies, and for road perfection, until we make a different type of engine and once and for all get over torque reactions and over-running vibrations. Our car 18-EX. is quite good with 4 feet, especially now the dash has been slacked off from the scuttle. It is abominable with only 2 feet and promises to destroy the bonnet also in a few weeks - (rough roads and shock dampers at over 100 lbs.- splendid riding qualities, which naturally make the frame worse.) Supposing the side frames are stiff in vertical bending I cannot see that it matters where the cross members are. The angle which they have to pass through is so small that it is difficult to see how even many large tubes (naturally at their best if evenly spaced) can give the frame much stiffness compared to the bodywork, which might be good if steel, but as coach built is quite unsuitable for such duty. | ||