This is a Pundit light – with generator, switch gear and a lantern (stowed on the back of the trailer during transit). The 8 tesla coils seen bottom right drive the 8 * 400-watt neon tubes that flashed two letters in Morse code. The letters were the I.D. code of the airfield. Once deployed, the ID code was set on the control disk and when required, ground staff would start up the engine and then activate the beacon in accordance with the instructions of Air Traffic Control or flying control. A Coventry-Climax 16.9hp engine powered the lights.
There are two of these of the SS Thistlegorm – often misidentified as armoured cars on a Rolls Royce chassis. Leaning against one of the Pundit Lights is a stack of Westland Lysander wings.
The pictures above include one that shows the Pundit light itself in its stowed position on the back of the trailer. When in use, this was mounted on the top of the trailer. Pundit lights were not always located on airfields. Sometimes they were located at a distance from the airfield – for example, ten miles due south. Pilots would locate the beacon and then fly ten miles north to find the airfield.
The components of the 3kW beacon were:
– Brockhouse forecarriage type trailer chassis
– Coventry-Climax 16.9hp engine – type ‘E’
– GEC 5KVA 230 volt single phase alternator
– GEC Exciter, 106volt, 3.22amp
– GEC 1/15hp 230 volt flasher motor
– Lucas type ‘C45’ 12 volt generator
– Lucas RF91-L6 voltage regulator
– Visco air filter
– 4 KVA single phase 1:1 transformer
– 8 off Tesla coils
– 8 off 400 watt neon tubes and resistances
– 8 off chokes and condensers
– Dimensions LWH 15ft6in x 7ft 6in x 12ft 3in.
Many thanks to Red Sea Water World and Ted Angus for the photographs of the pundit light which were so much better than mine.
Thanks also to the Aircraft Research Group for helping with the identification of the Pundit Light on the SS Thistlegorm.
There are other aviation finds that I located on this classic wreck, including: