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 comparison of automotive components including springs, steering gears, engines, and axles from competitor vehicles.
| Identifier | ExFiles\Box 154\2\ scan0044 | |
| Date | 12th October 1937 guessed | |
| -2- They go to a maximum stress of 90000 lbs/in² uncorrected in the front coil springs, and have had no trouble with these. They are made by the Tempered Spring Co. [Handwritten note in top right: Les, How do prices compare with Steel Cork.] They are fitting a Marles steering gear of the double roller type, bought complete from Adamants, and appear to be as dissatisfied with them as others. The type of column they buy has a needle roller bearing at the top end with inadequate means for ensuring that the rollers stay there, and they have had one case in which a needle roller fell down to the box at the bottom, and found its way into a gap between the roller and the cam, so jamming the steering completely. They told us that the original Marles patents expire next year, and that then the only one which will remain will be one on the side adjustment of mesh of cam and roller, as used in our Phantom III box. This 15 h.p. Daimler has been designed for an 18 h.p. 2½ litre engine which is not yet ready for production, and the performance will obviously be improved when this engine is fitted. We saw an experimental engine of this type and were told that it developed 70 b.h.p. and has a maximum B.M.E.P of 112 lbs/in². The general construction of this and the new Lanchester 14 h.p. engine are similar. The integral head and cylinder block have been discontinued for three reasons. They say the chief one is Agent's prejudice; the other two are, first, that any engine noise, particularly valve noise, appears to be magnified, and secondly, the impossibility of obtaining adequate valve size for any but a short stroke engine - in other words, the horse power obtainable from a given R.A.C. rating is limited. The arrangement of push rods and sparking plugs is similar to that employed in the 25 H.P. Vauxhall, the Daimler 18 engine having holes drilled through bosses in the cylinder head casting, and the Lanchester 14 having inserted tubes for the push-rods. The tappet guides are integral with the cylinder block-crankcase casting, and thimble tappets are used. [Handwritten note: Swell - What are these.] The new worm rear axle on this Daimler 15 is a vast improvement on the old, apparently entirely owing to the absence of distortion. On the old axle, there was a deflection of .012" to .014" at the tooth contact, measurable by means of indicators, whereas on the new axle no deflection is measurable, but they know from tooth marking that it is actually .0015" to .002". | ||