During the world wars, various barrage balloons were used to protect targets from low-flying aircraft or similar threats (e.g. V-1 flying bombs), in particular by Britain.
What lifting gas was used for such barrage balloons – the highly flammable hydrogen or the rare and expensive helium?
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8$\begingroup$ Note that barrage balloons are not manned and don't carry anything. Nobody really cares if they burst into flames. $\endgroup$– Jan HudecNov 24, 2015 at 19:34
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3 Answers
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6$\begingroup$ +1. Although the other answer is more complete, it ultimately relies on inference. By contrast, this is a primary/secondary source. $\endgroup$ Nov 25, 2015 at 6:41
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$\begingroup$ @imallett, thanks. In many ways I like the answer provided by Peter better than mine. But the OP asked specifically about barrage balloons, and I thought all the other stuff was extraneous to the original question. Certainly the BBC ought to be a fairly reliable source to cite. $\endgroup$– BillDOeNov 25, 2015 at 19:03
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Hydrogen.
Helium was scarce or not available at all. The only substantial source was in the United States, which had a capacity of 24 million cubic feet (680,000 m³) in 1940. Its commercial and military needs of that time were just a quarter of this amount.
If you look at this statistics of word helium production, you will notice that only from 1963 on did total world production of helium differ from the amount produced in the US. You will also note that production shot up from 45 metric tons in 1940 to 608 metric tons (3.6 million m³) in 1944, which is most likely to cover the increased need for war. Also, exports only started in the 1960s. Sadly, the MYB statistics have no export data from earlier years.
This lets me conclude that only hydrogen was available in all other countries throughout the war, and only the US used helium. The US production was needed to fill anti-submarine observation blimps. One K-class blimp had a hull volume of 404,000 to 425,000 cubic feet (11,480 to 12,035 m³) and needed to be topped up every few weeks. A total of 134 of that type were built, and just filling them once would already had consumed half of the helium produced in 1944, the most productive year.
US Navy K-class blimp in WW II (picture source)
answered Nov 24, 2015 at 20:50
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Hydrogen was used in Barrage Balloons flown by the British. I understand that the US protected their supplies of the much safer Helium.
