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).
Technical report on front spring design, engine specifications for six and eight-cylinder models, and transmission systems.
| Identifier | ExFiles\Box 173\1\ img350 | |
| Date | 19th February 1934 | |
| -2- That by using a 44" long front spring which gives them a reasonable top leaf thickness, and having the engine mass where it is they get good steering; that their girder frame-body construction is a great factor of safety. Also that it eliminates the frame vibration that causes often that high frequency shake so annoying to passengers. They have been working on this weight distribution theory for a long time. They showed me forty models used in wind tunnel tests and for judging appearance. The engine has been moved forward something like 20". ENGINES. They now build only sixes and eights. The six is a four bearing, 60% of the crank only balanced; half speed period 2800. Journals 2.5" diameter; pins 2.062 dia. Pin length 1.242. Two centre bearings 1.25 long. The eight has five bearings, four per rev. period 3200 r.p.m. No difficulty in dealing with this with a rubber damper. A rubber damper also deals with the six half speed. They say that these rubber dampers do not depend on hyterises as there is little or none in the rubber, but on tuning (this seems scarcely credible). They tune them to 60% of the crank to get the best results. They are so emphatic about their efficiency that I have sent two back to you to try. They look absolutely fool-proof. They should be about right but you can tune them by adding to or taking from the inertia. They are using Cleveland strip lead bronze bearings throughout. TRANSMISSIONS. They are using an over-speed gear this year which is a planetary scheme that automatically functions at 40 m.p.h. They are talking about worm axles to get the propellor shaft down. I presume they will succeed in making them work in spite of what we know of Stutzes, etc. | ||