Aboard aircraft, especially smaller ones, there is a need to conserve weight wherever possible. This becomes especially important on military aircraft where the aim is to extend range and payload for munitions wherever possible. During World War II visual signalling via lamp between an aircraft and the ground was still commonly employed, unfortunately the lamps were usually heavy and bulky such as in this example we looked at many years ago here. It therefore made sense to issue a lighter weight signalling lamp and the result was the ‘Signalling Lamp Type B’, a far lighter lamp that was made of pressed metal rather than large castings:
The accompanying manual provided the following description:
The signalling lamp, type B, is intended for visual signalling between aircraft in flight, or for air to ground signalling, by day or by night. When used in aircraft the lamp is plugged into a socket connected to the general services supply, and when used on the ground It is connected across a standard 12-volt or 24-volt accumulator depending on the rating of the lamp filament supplied.
The beam of light is focused by means of sights attached to the lamp body. Signalling is carried out by breaking the current to the lamp filament by means of a trigger switch on the right hand handle, the time taken for the filament to light up and black out being sufficiently short to permit signalling at a speed of between 8 to 10 words per minute.
This lamp was to see long service, being produced and issued into the 1980s, although later examples have white printed NSN numbers. This example is wartime in date and so has the Air Ministry marking, together with a stores code of 5A/2334 stamped into the metal work:
The lamp has a pair of handles on the rear to hold it steady, and a small trigger that activates the lamp itself:
The lamp has a large reflector for the bulb, with the glass, held on by a collar and a pair of spring clips:
Undoing this allows the lamp to be disassembled for cleaning and repair:
The lamp was originally provided with an extra filter lens in red glass as well, but this is missing from this example. The user’s manual gives a complete exploded diagram of the lamp and all the components:
To aim the lamp accurately, a sight is attached to the top of it, although the rubber eyepiece is missing from this example:
The lamp was originally housed in a small wooden box that kept it secure when not needed, although this example is missing this. The lamps were carried aboard many classes of aircraft including transports, flying boats and bombers to allow inter aircraft communication, or contact with the ground where radio was not available or suitable. This example has been rewired with a 1970s era cable of the type used for table lamps! At some point I will track down a more appropriate cable and perhaps even the correct type of plug to finish off the lamp and then I will be able to see if it still works!