BLAST BOMBS

Timaru Herald, Volume CXLVIII, Issue 21784, 14 October 1940, Page 8

BLAST BOMBS

Develop Wind Stronger ■ Than Tornado I British Official Wireless RUGBY, October 11 The bursting of German bombs over Britain has forced the special use of the word "blast” into the language i and for the last five weeks, particularly in London, the strangely unpredictable effects of blast, noticeably on glass windows in the districts affected, has been an absorbing topic of conversation. Experimental work carried out in the last few weeks by the Civil Defence 1 Research Committee with the aid of | delicate apparatus has upset many preconceived ideas and popular beliefs. Blast is not so terribly destructive as is generally held, but that is only because the effects are very local. It creates, in the immediate vicinity of an explosion, a wind six times as violent as a tornado, which is credited in America with an air speed of 500 miles an hour. ( But the wind, which is i eally gas ' from the bursting explosive, is very short-lived. Beyond a distance of 30 feet from the burst of an ordinary bomb of 5001 b weight, it fades away rapidly and at 50 feet it is almost innocuous so far as the destructive effect on buildings is concerned. Splinters’ Great Velocity Splinters from bursts will still have a velocity of 4000 feet a second at 50 feet, nearly four times the speed of sound. Within a radius of ten yards blast exerts its full force, and from the point of view of effect, anywhere in that circle counts as a direct hit. Blast alone, however, is not believed to be lethal, except at very close range.

It might kill through shock to the heart or lesions of the lungs owing to the mouth having been closed, but not through the mere velocity of gas. One of the most curious blast effects was seen when a bomb struck a block of flats in London some days ago. It cut the building in two, with the result that people in the streets could see half of two bedrooms with the beds undamaged but perilously near the edge.