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).
Dynamo output, weight reduction, and lighting for a chassis.
| Identifier | ExFiles\Box 60\1\ Scan077 | |
| Date | 11th February 1929 | |
| EFC. H.J. ) FROM R.{Sir Henry Royce} D.A. E.{Mr Elliott - Chief Engineer} ) (At Le CanadelHenry Royce's French residence.) X7660 SECRET. ? R2/M8.2.29. REC'D AT WW. 11.2.29. SS.{S. Smith} CHASSIS. DYNAMO OUTPUT. X.7660 We must not add weight to this chassis, and we must work hard to obtain our results by the simplest possible means. Like Mr. Ford it seems that I must spend much time to prevent our cars being overburdened by weight and complication. Regarding the dynamo output we must try to economise current, and there is the first possibility of the side lamps which are naturally on for the longest period, and often when the car is standing for hours. Moreover the bright ones at present used are definitely objectionable. Is there anyone who can regulate this altogether objectionable practice? Perhaps it could start with the coachbuilder's drawing. The tail lamp may be of a very inefficient type, taking too many watts. Next comes the speed of cutting in. You say that the higher output is 200 dynamo revs. later = 133 engine revs. The engine is geared nearly 10% slower, and the car is moving 10% faster compared with a few years ago, which seems to me to cancel. We must not increase the weight, but we can test: (1) Make the present do larger output by use of green lamp scheme. (2) Use the armature with fewer turns per section (test for cutting in speed.) (3) Make a new armature with about 5 to 10% more sections. I do not think the situation justifies expending much money on a new size of dynamo. Moreover when I propose to use the larger output EFC. says it will damage the batteries. I agree that if the green lamp scheme becomes reliable we shall probably fit it to our cars, but it is thought that it was not an essential RR. feature. R.{Sir Henry Royce} | ||