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Show Captive Balloons Are to Help Defend English Cities Against Air Raiders In a recent lecture, Air Commodore Commo-dore J. G. Hearson partly lifted the veil of secrecy surrounding the balloon bal-loon barrage scheme, in which a large number of captive balloons will add to the protection of cities against air raiders, says the Illustrated Illus-trated London News. Each balloon is handled by a lorry-winch with a crew of ten. Toward the end of the World war "balloon aprons" were used in the defense of London. They were formed by tethering four or five balloons in a line and stretching a network of wires between them. The balloon barrage of today is not in the form of "aprons," but consists merely of the cables by which tlie balloons are held captive. cap-tive. At first sight, such a defense may appear rather diaphanous; but, if simple calculations are made, it will be found to be far more effective ef-fective than many might imagine. Assuming that the span of the wings of a bomber is 70 feet, and that that bomber passes through a line of balloons tethered at 100-yard intervals, there is about one chance in four of the aircraft hitting a cable and one chance in two if it makes an "in-and-out" passage, a formidable formid-able risk which no attacker could afford to continue taking if the cables are lethal; that is, capable of destroying any airplane coming in contact with them. The cables are so thin that they cannot be seen from a traveling airplane, even by day and in fine weather. The role of a balloon barrage is to deny passage to aircraft below the barrage height over the defended defend-ed area; thus driving the attackers to an altitude at which they can be dealt with by anti-aircraft fire and interceptor fighters. |