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).
Upcoming changes in headlamp dimming regulations and their potential impact on existing lamp systems.
| Identifier | ExFiles\Box 61a\2\ scan0122 | |
| Date | 6th January 1932 | |
| Cx.{Major Len W. Cox - Advertising Manager} from Hs{Lord Ernest Hives - Chair}/Wst c. Pn.{Mr Northey} c. Da{Bernard Day - Chassis Design}/Ev.{Ivan Evernden - coachwork} X6116 Hs{Lord Ernest Hives - Chair}/Wst.2/AD6.1.32. X1357 CHASSIS HEADLAMPS. We have heard indirectly that the Ministry of Transport are contemplating standardising this year, a method of dimming headlamps. The scheme favoured is the twin filament bulb similar to the Lucas Graves in which the dimming filament is placed slightly out of focus and hooded so that the light is thrown to the top half of the reflector only. This would mean that in time our three lamp system would be illegal in spite of the fact that it has proved the most effective and reliable means of light beam control. At the same time as this dimming law comes into force, the wattage of headlamp bulbs will be reduced compulsorily to 36 watt. We are ascertaining if there is any reliable official information available with regard to future regulations. In the meantime we have on R's car 20-GIV, a set of Lucas Graves headlamps, and we also have for trial some Philips double filament "Duplo" bulbs incorporating the hooded filament. Our experience in the past with Osram lamp bulbs of this type has been disastrous and as many as 6 bulbs have been used in one night during high speed trials in France. Hs{Lord Ernest Hives - Chair}/Wst. | ||