NIGHT FLYING

New Zealand Herald, Volume LXXIII, Issue 22434, 2 June 1936, Page 10

NIGHT FLYING

AUCKLAND EXERCISES

SEARCHLIGHTS USED SOUND LOCATOR EQUIPMENT FIRST DOMINION TESTS Searchlights and sound locators, which now form part of tho anti-air-craft defences of nearly every large city, were used together in New Zealand for the first time last night, when a detachment from tho anti-aircraft section of the Royal New Zealand Artillery carried out exercises in Auckland in conjunction with an officer of tho Royal New Zealand Air Force, who (lew a Hawker Tomtit from tho Hobsonvillo air base.

Three of the new mobile searchlights were in operation, and for nearly an hour thev swung long white pencils of light backward and forward across the sky between Rangitoto and tho military camp at Narrow Neck, seeking tho aeroplane hidden in the darkness 5000 ft. above, and betrayed only by the droning sound of its engine. Five times their patient quartering of the sky was successful, and tho aeroplano was trapped in the three beams like a small silver moth unable to resist tho attraction of a lamp light. Then it disappeared into the darkness again, and the searchlight's continued their hunt until the machine was headed for homo. Sound Locators Locating a high-flying and fast-mov-ing aeroplano with a searchlight .is not an easy job, and, although the searchlights used at Narrow Neck last night had an extremely high candle-power strength and a range of about 30,000 ft., they could not bo operated so efficiently without tho sound locators. These sound locators are worked by three men, and consist of a' cluster of trumpets mounted on a stand to pick up tho sound of tho engines of approaching aircraft. Two men determine the direction and elevation of the aeroplane from the sounds which they hear through stethoscopes, and the third man uses their observations to direct tho operator of the searchlight by telephone. Two "spotters" placed 50yds. on either side of tho searchlight watch for aeroplanes through night glasses, and call to tho operator when the target is observed. Tracking the Plane

Conditions were all in favour of aircraft when Flying-Officer R. J. Cohen flew the Hawker Tomtit over the Narrow Neck camp last night, ihe moon was shining brightly, and it was impossible to see the machine against the deep black sky. The pilot switched on one of his wing tip lights, and then the sound locators picked up the sound of the engine, reduced from a roar to a steady drone by reason oi the, height at which the machine was flying. Three lights swung slowly into the air, the carbons, of the electric arcs in the searchlights hissed steadily, and the . generators on the lorries of the mobile units in the rear throbbed busily. „ The hunt was on, but the process ot tracking down the quarry was not a swift one. Slowly and steadily the beams searched the skv from the Rangitoto beacon to a point opposite St. Heliers, but it was nearly five minutes before one of the "spotters" called out "target seen" and the operators depressed and elevated their searchlights to keep the Tomtit safely in the long rays of light for the first time. The pilot gave the units two chances during the evening, for while the beams were vainly sweeping the &ky above him, he switched on his red . and green wing tip light?, making the Tomtit easily visible to the watchers on the ground. As a conclusion to the exercises, the pilot dived his machine down the dimmed beams of the searchlights, turned and twisted in the rays which silvered the wings and fuselage, and then roared off into the darkness.