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).
American engine design features and summarizing potential development paths.
| Identifier | ExFiles\Box 178\2\ img202 | |
| Date | 23th February 1934 | |
| -3- reasonable service (T. slot as used by Cadillacs). The crankcase and cylinder block are admittedly cast en bloc cast-iron with double flywheel bearing cap and double central flange externally about the crankshaft centre line - this is now general - but the unit is lighter for its displacement than almost any similar American unit I understand. I will try and get the actual weight. I send an instruction book, which gives general outline of engine, gearbox etc. They have a rubber type crankshaft damper. Therefore there is nothing mechanically that one can put one's finger on as out of the ordinary to give the result. Thermodynamically they have done a good deal on combustion chamber design to give smooth burning, but there is a section here who say a pound of rubber is worth a cwt. of combustion chamber theory. Anyhow, one cannot conjecture what this is worth as we have done little of such work ourselves. The engine mounting is interesting and from enquiries I believe this is responsible for more than half the smoothness. It is exactly as on the eight. The large block of rubber at the rear and the two pneumatic cups in front give exceptional softness which we have not yet tried. I send blue prints of the parts in question which you should be able to get from Hudsons, England. Hudsons say that they have tried this against the Chrysler floating power mount and are just as good at less cost. Summarising - (1) Here is an engine mounting well worth fully investigating whatever type of engine we may build in the future. (2) Here is a six cyl. engine, of the cheapest possible construction, containing a number of features that we should condemn theoretically as being inimical to power and smoothness; i.e., three bearing crank with relatively small dia. pins, rubber crank damper, splash lubrication, very light flywheel, side valves, and long stroke for the bore. It is exceptionally smooth in the car and equals our 1934 25 HP. R.R. power output per c.c. Hudsons will be the first to admit that they have obtained this result by spending money freely on development and testing, and it should urge us to push on with our single cylinder units and other research. | ||