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).
Comparative analysis of competitor engine, gearbox, and crankshaft damper designs.
| Identifier | ExFiles\Box 178\2\ img203 | |
| Date | 23th February 1934 | |
| -4- We ourselves can quickly find out how well this unit will stand up on the road. I met an Englishman who had done 25,000 on last year's model with no trouble. Hudson's output is now reaching 1,000 a week. It would break them if their cars would not stand wide open throttle running on American highways for reasonable periods at any rate. (3) This is not saying that the six is as smooth as the eight. At higher specific outputs the difference would probably show up in favour of the eight much more than with 5.78 C/R.{Sir Henry Royce} Again, these two engines; i.e., the 8 and the 6, have the same bore, 3.00". If the six was brought up to the 8 total displacement it would probably become a rougher unit. The point is we have to live with the six for some time yet and I believe we can learn how to get better results from it by studying this Terraplane. (6.25 & 7-1 heads are available). GEARBOX. This has had a great deal of money spent on its development. One of the secrets is the use of a special S.A.E. steel 3440, which they say gave them some three times the resistance to fatigue of some of the cheaper steels. They have modified the box slightly from the one we have by putting needle bearings on the pilot and a ball thrust there instead of Bakerlite pad. I send a print of a gear, but it is worth pulling the box down and examining it. The back-lash on the internal gear must be held to 1 1/2 thous. If the Terraplane can get away with this, we should certainly be able to use the Peregrine box on the Bentley. CRANKSHAFT DAMPERS. As far as I know 90% of the American cars are using rubber crankshaft dampers. There was no trace of the half speed period on the Terraplane 6. Its damper differs from some of the others in that the rubber is not vulcanised, it is merely squashed into the flywheel under pressure. They say it quickly vulcanises itself. Both Packards and Essex are emphatic that they were always in trouble with the Lanchester damper and are nearly free from it with the rubber type. | ||