NIGHT MOVEMENT

Wairarapa Times-Age, 1 February 1941, Page 7

NIGHT MOVEMENT

PRECAUTIONS BY GERMAN CONVOYS ■ — WELL LIT SECRECY. I . HOW THE SYSTEM IS WORKED I A recent issue of "The Motor" stai ted that wherever the Germain altack- ) ed. it practically always started : dawn, preceded by overnight manoeuvI ring into position and considerabk I movement under the cover of darkness I bringing forward reserves, supplies ! and equipment. Thousands of ve- ; hides were used, but to facilitate such I large-scale movements sr> <■ ; : - n lof lighting was developed, <me which I would not readily be seen from the air •yet would allow convoys to travel f.,-v I The system comprises a hooded head I lamp and a special rc:.r lump Tin j former gives an even spread f hgii up to a distance of 35 to 45 y. : I lighting anything up to a width of 23 I yards. The beam is controlled by a ■ rheostat switch. Rear lighting takes th- form <>f m interesting and ingenious drarawe radicating lamp built in conjuration with stop and tai) lights. Tile head lamp has, to make possible a -need of, about 20 m.p.h. in convoy with mt the light being detected by aircraft nr ground observers, and the distance indicating lamp enables drii vers to maintain correct intervals be-1 tween vehicles. Four panels arc cut into the face of the distance indicating lamp, through which little green lights shine. They are spaced fairly close together in pairs with each pair separated by about 3in. If the driver is able to discern the four green lights on the ve-| hide ahead, it :s an indication that he I is much 1 dose. The individual green lights are visible up to a distance I of 27 yard.-. ; He has to diop back slightly, in-1 creasing the gap between the vehicles j until each pair of lights merges to-I gather, so that all the drivers sees is two green panels. This is how they would be visible up to a distance of 38} yards which is the spacing considered correct for convoy work by the German authorities At anything above that the panels merge again to appear as one light indicating to the driver that he is ton far away from the car | ahead. KEEPING UP THE SPEED.

With this scheme it is possible to J maintain a convoy speed considerably i higher than that normally possible } with a single Door rod light mid dim | headlamp illumination. Perhaps the j most essential factor is that distances can bo judged so well. The hooded head lamp is designed on an entirely new principle having a very narrow strip-form reflector on the elliptoid principle taking advantage of converging rays of light from 36-watt bulb illumination. The hood actually comes down below the level of the head-lamp aperture: all upward rays are eliminated by virtue of the design of the reflector and ! the hood tends further to cast the light i downwards. The beam actually is 18in. ! high at a distance of 25 yards from the | car. It strikes the road about 12 j yards ahead of the vehicle giving a I good spread. i The rheostat switch enables thej I beam to l>e controlled in three differ-; lent strengths and owing to the even, | weak light disttibution, on the ground.] recognition by aircraft above a height i iof 1500 ft. with the dimmest beam, I I above 2700 ft. with the medium beam. I mid -1800 ft. with the brightest, is made! impossible. On very dark nights and| with long convoys tin* beam strengths,’ are reduced; in any case it is probably j only the leading vehicle that would; use the brightest, the others relying; upon the weakest beam in conjune-‘ lion with the green distance indicators.; Actually, with the distance-indicating j equipment there is really m> need to! use headlamps.