Physical Science, Measurement and Instrumentation, Management and Education, IEE Proceedings A

From September 1914, the admiralty accepted responsibility for the air defence of the United Kingdom and, from September 1915, it was also in charge (on a temporary basis) of the gunnery defence of London. The inadequacies of the country´s air defences against the marauding attacks of Zeppelins was much exposed during the early months of the war. In October 1915 the Admiralty´s Board of Invention and Research considered a scheme, submitted by F.W. Lanchester, for illuminating the lower strata of the atmosphere, from the south to the east coasts of England, so that Zeppelins would be located in silhouette by aircraft flying at a higher altitude. Tests showed the limitation of the method. After the war, the Admiralty initiated some shipboard trials on acoustic methods of detecting aircraft. Later, in the 1920s, the Admiralty commenced work on the ´Hornet´ project. It was hoped that a pilot-less aircraft/missile could be guided by W/T means to the vicinity of an enemy plane, so that ´homing´ equipment would then cause the aircraft/missile to impact against the attacking target. Numerous methods of detecting aircraft were tested but none were felt to be suitable for a practical system. The author highlights the soundness of Watson-Watt´s suggestion that the most attractive scheme for detecting aircraft was that ´in which zones of short-wave radio illumination were set up through which an approaching aeroplane had to fly´.<>