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).
Unsatisfactory dashboard instrument illumination and comparing it with Terraplane and Essex models.
| Identifier | ExFiles\Box 62\2\ scan0256 | |
| Date | 30th January 1934 | |
| S/W Hs{Lord Ernest Hives - Chair}/Wst WST rb{R. Bowen}135 me Se c. to C. c. " Hs{Lord Ernest Hives - Chair}/Wst. Illumination of Instruments. CxE/KW30.1.34. Sg{Arthur F. Sidgreaves - MD}4/E29.1.34. I am sorry you find that the illumination of our instruments is still unsatisfactory although it is so much better than it was previously, and I am afraid I must agree with you so far as the speedometer and the clock are concerned. This would be so much improved if there could be about another 1/2" space between the lamps and the dials so that there would be a fairly uniform illumination of the speedometer and clock. I notice you have already drawn the attention of Hs{Lord Ernest Hives - Chair}/Wst to your criticisms, and I am therefore sending him a copy of this also, so that he may realise that we should like some further suggestions regarding our own method of illumination quite apart from whether we fit up an experimental set of instruments having luminous dials of the Terraplane type. I think we ought to try such a scheme as an alternative, although it is very easy to get too much light on your instrument board for night driving and become r ather dazzled by the brilliance of a well lighted patch in front of you. For instance, if we adopted the Terraplane scheme we ought to adopt it for all our instruments, and we should have no less than six dials fairly brightly lit up, and I personally feel convinced there would be much too much dazzle from such a patch of light and it would make driving at night rather unpleasant. I gave the Terraplane a run in the dark last night for a few minutes to confirm my impressions of dazzle, and although there is only one instrument on the Terraplane lit up in the way under discussion, i.e. the speedometer, I found even that one inclined to be trying as regards the large patch of light in front of the driver. I have little hesitation, therefore in saying that with all the instruments lit up in that way we should find it very embarrassing when driving at night. Incidentally I found the legibility of the Essex speedometer at night very difficult. The hand is almost invisible and by making an immediate comparison with our own scheme I quickly came to the conclusion that so far as legibility is concerned our present scheme is infinitely superior. If, therefore we could improve our own lighting as suggested at the beginning of this memo I am certain we shall find few people will complain of it. Will Hs{Lord Ernest Hives - Chair}/Wst therefore approach Smiths as suggested by Sg{Arthur F. Sidgreaves - MD} in his memo, and let us hear as soon as possible what can be done. | ||