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).
Comparing the performance of various dynamos for the Goshawk.
| Identifier | WestWitteringFiles\H\November1921\ Scan20 | |
| Date | 11th November 1921 | |
| R.R. 235A (50 T) (S H.{Arthur M. Hanbury - Head Complaints} 936, 19-2-21) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 3008 To R & E.{Mr Elliott - Chief Engineer} from EPC. c. CJ. & FN. c. Rg.{Mr Rowledge} & Ds. c. Hy.{Tom Haldenby - Plant Engineer} & MP. c. RR Inc. EPC2/T11.11.21. ORIGINAL X.4359 - DYNAMOS FOR GOSHAWK. We now attach small photostats of comparative open circuit volt speed curves and hot condition ampere output speed curves of the various dynamos submitted to us for the Goshawk. It will be seen that the Lucas E.S.R.R. single field third brush controlled machine is the earliest to operate, whereas the C.A.V. "D.E." machine gives the biggest output curve. It may, or may not, be considered that the excess output area of this Lucas machine over the C.A.V. in the early stages is more valuable than the excess of the C.A.V. over the Lucas in the later stages. One would, of course, like to have seen a curve of similar shape to that of the Lucas E.S.R.R., but increased proportionally so that its peak value was 10 amps. It would appear from the results obtained [handwritten: obtainable] on the various machines that such a curve would be favoured if just the right condition was given [handwritten: known]. It is very difficult to say which of these two output curves is the better for the average case, though from your note we judge that you consider the C.A.V. to be the better. The point of intersection of the two curves corresponds to a chassis speed of 17.8 miles per hour, - and the speed at which the total area of the two curves has arrived at equality would appear to be, without actually Contd. | ||