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).
Troubleshooting on the Phantom model and comparing different wattage headlamp bulbs.
| Identifier | ExFiles\Box 5a\3\ 03-page121 | |
| Date | 23th November 1931 guessed | |
| (2) We have got over the trouble on the Phantom, we should therefore be able to reproduce success on the 20 HP. We will endeavour to give you the differences in m.p.h. when it is safe to drive when using 36 watt bulbs as against 60 watt bulbs. It is comparatively easy however to obtain a diagram of the relative powers of the different bulbs, by fixing up a screen of tracing paper with an oil spot of a certain diameter in the centre, and setting a headlamp at a certain distance away and focussing it on the spot, then by changing the bulbs you can obtain the varying amount of increase in light obtained, and get practically the true values of the bulbs. This has to be done in a dark room. We are not at the present time using the discharge resistance at all, therefore, the drain from the battery is 12 amps. for approximately 3.1/2 hours. With this arrangement the battery charge is just being maintained. GWHancock G.W.H. | ||