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).
Comparison of dynamo electrical performance, drive ratios, and output curves for various chassis models.
| Identifier | WestWitteringFiles\L\2Jan1924-March1924\ Scan61 | |
| Date | 3rd March 1924 | |
| Contd. -4- EFC2/TS.3.24. is not quite as high a curve as corresponds to the general specification setting, this latter having a peak output of about 10 amperes in place of 9, so it is possible that the actual comparison is slightly more favourable to the RR. 20 HP. than shown by the curve. It should have been stated against the scale for 40/50 HP. chassis M.P.H., that these are on a basis of dynamo revs = 1 1/2 times engine revs. (It was purposely arranged like this so as to make the curves definitely comparative as regards their contemplated application to the EAC.3.). New curves are therefore now issued containing this modification and addition, and also the curve given by the figures contained in the general specification of electrical performance of dynamo for 40/50 chassis, to which we are of course working in the case of the EAC machine. This shows up the difference between the contemplated application of either the Lucas or the RR. 20 HP. and the output which we say is desirable for the 40/50 car. Clearly, the comparison of the RR. 20 and the EAC. with the Lucas E.575 on the present 40/50, would show up the Lucas output on a m.p.h. basis still more favourably relatively, because the present standard drive ratio from gearbox to dynamo is 1.7 instead of 1.5. Hence in the application of either machine in the EAC, the performance in the early stages would be definitely bad, and the Lucas superiority is more apparent than real because the battery would have to suffer Contd. | ||