Bovine Airships

[sonofcmx]

Having watched Coast on TV last night I learnt that airships relied on internal gas bags filled with hydrogen.

These bags were made from cow intestine, their caecum to be precise. The gas-tight lining was dried and formed into each bag. What staggers me is that each airship took ONE MILLION cows!! They had to be shipped in from America to keep up demand. When did we find a replacement and what was it?

Laurie

[centurion]

Only rigid airships used gas cells (not bags) and they were not made in this fashion each cell being quite big. The first Zeppelin had 17 gas cells made of specially treated linen. Nearly all British WW1 airships were non rigid with all the gas contained in a single envelope. What were you smoking?

[NigelS]

I don't have any knowledge of the gas cells used in early airships, but I do know that the material made from the outer layer of cows' caeceums was known as Goldbeater's skin, so called because it was used to separate layers of gold when it was being beaten by hand to form gold leaf using techniques which date back to the Egyptian pharaohs, possibly earlier

NigelS

[centurion]

Ok here is what I think is actually the case. Initially Zeppelin made gas cells from specially treated linen but experiments were made using goldbeaters skin which was already used to line some balloons in Britain. Goldbeaters skin is made from cows intestines and is the thin outer skin from these (human intestines produce much the same but lower quality and much less and there are problems in acquiring it!) Indeed almost any animal can be used. However in South America vast numbers of cows and oxen were slaughtered for meat for export to Europe and the USA. Techniques were developed to retrieve the intestines and remove the thin gas proof skin which was exported in large quantities for all sorts of things.. This was used to line the gas cells of some rigid airships. Britains first rigid airship had cells lined with goldbeaters skin. However it did not become a standard. The Germans continued to experiment with alternative methods as did other countries. With the advent of WW1 Germany could not obtain goldbeaters skin from S America and her own production was inadequate and so most Zeppelins did not use it. British airships in WW1 were primarily non rigid and the envelopes were made from tough rubberised fabric. It was not until about 1920 that a proper study was made into the use of gold beaters skin to line gas bags. I've read the 1922 report. Thereafter it began to be used much more extensively for airships as being essentially a by-product of the South American meat industry it was cheap. However viable alternatives had already been developed (partly as a result of Germany's wartime experiences) Goldbeaters skin was difficult to work with (it is very fragile and joining all the sheets together and putting them on the inner surface of the cells required special glues. Using it was labour intensive and the cost advantage quickly waned. Helium is much less diffusive than Hydrogen and I don't think the American rigids needed it anyway.

[NigelS]

A search in the Flight archive (Click) using 'goldbeater' as the search term finds quite a bit on the material; similar on the cranfield 'Aerade' site (Click) finds all you'd probably ever need to know about it and its variants from a 1922 report by America's National Advisory Committee on Aeronautics (Click)

NigelS

[Adrian Roberts]

I also heard the presenter say one million cows, but although I know it was a large number I took that figure with a pinch of salt. But as they were talking about HMA1 Mayfly, the fact that they were used at all ties in with Centurion's assertion that they were used in the first British rigid.

[whatisart]

Thought I'd join in on this one. Time for some facts I think.

Goldbeaters' skin was very much a standard material used for the gas cells of British and some non-rigids. In fact its use in lighter-than-air craft goes back as far as the 1780s in France.

According to the Naval Air Service Manual (1915)... "Gold-beater's skin is very gas tight in proportion to its weight and thickness. To give, however, sufficient strength it requires to be thick and heavy. Unless varnished, it absorbs a great deal of moisture from the air in humid weather and this increases its weight. It is extremely durable and lasting and withstands the sun's rays very much better than rubber fabrics. Beta's envelope and most of the small spherical balloons are made of gold-beater's skin."

As far as I can see pretty much every British rigid airship and some non-rigids used gas cells made of goldbeater's skin. Nulli Secundus was made entirely from skin. It seems the gas cells of the many of Germany's Zeppelins were made of, or used, goldbeater's skin (among other materials). The Germans only really started using goldbeater's skin for the construction of Zeppelin gas cells after the start of the war - but as a result of the war and blockades they had to rely on domestic production rather than imports. This is a fascinating piece from Capt. L Chollets 1922 report "Balloon Fabrics made of Goldbeater's Skin"...

"The collection of goldbeater's skins was very systematic in Germany during the war. Each butcher was required to deliver the ones from the animals he killed. Agents exercised strict control in Austria, Poland and Northern France, where it was forbidden to make sausages"

Much later, however, the Hindenberg's gas bags were made of a gelatinised latex developed by Goodyear.

Right up to the 30s goldbeater's skins continued to be used for the gas cells of airships of all nations. R101 was 777ft long, a volume of 5,509,753 cubic ft and 17 gas cells all made from goldbeater's skins glued to fabric. Graf Zeppelin's gas cells were made of goldbeater's skin bonded to linen. The USS Shenandoah used 750,000 sheets of goldbeater's skin. That's a lot of cow's intestines.

A bit of googling brought this up from the Danish Post and Tele Museum of all places...

"Goldbeaters skin is made from part of a cows intestine, the outer layer of the caecum to be precise, which is also called blind gut or even the appendix. The outer layers of the blind-gut are carefully stripped off into sheets of around 60 cm in length by 25 cm in width. They are then cleaned of fat by dipping the gut in a mild alkaline solution and scraped with a blunt knife. The cleaned gut is then stretched over a frame. One quite remarkably quality of this material is that separate sheets can be joined or welded when wet by carefully rubbing the overlap of the two sheets. Several layers can be made this way as well, for example, airship gasbags usually consisted of up to seven layers of skin.

The living tissues in the sheets grew together making a seamless and Hydrogen proof join. As well as being impermeable to Hydrogen it was also light and very strong, making it the perfect gasbag material. However it was very labour intensive and time consuming to produce. Supply of goldbeaters skin ran out during the First World War, forcing the Zeppelin Company to recycle the material from older airships as well as use an inferior artificial substitute for the construction of the gasbags. The poor quality of these wartime gasbags were considered responsible for the loss of many war-time airships and their crew."

My specialisation is really British naval non-rigids (specifically NS-class) but I find this subject fascinating. Just think of the poor people who had to prepare the skins.

[mickdavis]

CCI 43/2 is running another of Michael Dunn's fascinating articles on the development of British aviation and gives a take on James Templer - the true 'father of British Military aviation'. Templer employed an emigree family, the Weinlings, who had the knowledge of producing goldbeater's skin, long before WWI. The issue should be out within a couple of weeks.

[nils d]

Having watched Coast on TV last night I learnt that airships relied on internal gas bags filled with hydrogen.

These bags were made from cow intestine, their caecum to be precise. The gas-tight lining was dried and formed into each bag. What staggers me is that each airship took ONE MILLION cows!! They had to be shipped in from America to keep up demand. When did we find a replacement and what was it?

Laurie

And one million cows could provide the gas to fill it for a few years!

[Tina Bilbe]

Research into alternative light weight, gas tight, fabrics for airships, was being researched at Kingsnorth Airship Station near Hoo St.Werburg.