This is a PUNDIT LIGHT - with generator, switch gear and a lantern (stowed on the back of the trailer during transit.. The coils and dial are part of a mechanism which flashes two letters in Morse code. The letters are the I.D. code of the airfield. Once deployed the ID code was set on the control panel and when required ground staff would start up the gene and then activate the beacon in accordance to the instructions of Air Traffic Control or flying control. Most of the WW2 variants had Ford V8 engines.There are two of these of the SS Thistlegorm - usually misidentified as armoured cars on a Rolls Royce chassis.Leaning against one of the Pundit Lights is a stack of Westland Lysander wings.

Follow these links to see more about the items of the Thistlegorm’s cargo shown above and an article I wrote that was published in the UK Diver magazine in February 2007:
 

Westland Lysander
Blenheim Bomber
RAF Trolley Acculmulator
Bristol Mercury engine

RAF PUNDIT LIGHT

Link to Diver article - Plane Truth

Steve Cain’s Thistlegorm photographs

The picture to the left of this text shows the Pundit light itself in it’s 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. They were also known as aerial light houses.

Many thanks to Red Sea Water World and Ted Angus for the photographs which were so much better than mine.