"FLYING ONIONS"

Evening Post, Volume CXXVIII, Issue 116, 13 November 1939, Page 8

"FLYING ONIONS"

AN A.R.P. PARALLEL

MINES ON BALLOONS

The "flying onions" reported by Royal Air Force pilots to have been encountered over Berlin recall one of ths defences against air raiders planned in Britain and revealed in the middle of thio The name of this device when it,was under consideration by the Air Ministry was the sky mine, and it is an aerial counterpart pf the sea mine, laid in the track of enemy naval craft. According to unofficial descriptions at the time, the sky mine consists of a 9 or lOoz light gauge rolled steel canister filled with high explosive and floated by a six-foot balloon attached to a 40-foot length of fine wire. By regu. lating the size of the balloon and the amount of gas in each one, it is post sible to lay these aerial minefields •aS different levels, up to 35,000. feet, The total cost of the unit was said to be only about 3s when produced in quantity. The invention of the sky mine is attributed to. Major \H. J. Muir. The plane .which hits a balloon or wire would swing the mine against it, and the bomb would explode. The amount of explosive in one bomb would not be enough to destroy the raider, but would shatter a wing or fuselage and the terrific. air pressure of high-speed flight would do the rest. The bomb has four firing pins, so arranged that one of them must strike any object which hits a balloon or wire in .the aiir. Also included in the bombisa simpla timing device which works the detonator automatically after the bomb has been in the air for a fixed time. This is necessary so that the device may be self-destroying, and keep the air clear for friendly aircraft after a raid is over. The- plan is to use the wind to carry the' bombs in the direction of raiders, and to scatter them sat a variety of levels as soon as an air raid warning is received. The device has many ad* vantages. *It is inexpensive, the fragments after an explosion are said to be harmlessly small, and the minefields can be laid in any weather.

..' During the Great War strings of coloured lights hung from' parachutes were used for signalling purposes, and these seem to be the parent of the "flying onions"; the name itself Ha* also descended irom them.