Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: thedoc on 15/07/2012 07:30:02
-
Des Enright asked the Naked Scientists:
Hi Chris
How much water was created when the Hindenburg exploded? Was it created in the form of steam? Or did it fall like rain?
Thanks
Des Enright
Dublin, Ireland
What do you think?
-
Ok,
I found that the Hindenburg had a capacity of about 7,063,000 cubic feet / 211,890 cubic meters (http://www.ciderpresspottery.com/ZLA/greatzeps/german/Hindenburg.html) of hydrogen (at 1 atm).
The density of hydrogen is 0.005229 lb/ft3 (0.08376 kg/m3) (http://www1.eere.energy.gov/hydrogenandfuelcells/tech_validation/pdfs/fcm01r0.pdf) (at 68°F; 20°C, 1 atm)
211,890 m3 * 0.08376 kg/m3 = 17748 kg of hydrogen.
From the periodic table, hydrogen has an atomic weight of 1. Oxygen has an atomic weight of 16. Thus water (H2O) has an atomic weight of 2+16=18. The ratio of water to hydrogen would be 18/2.
So, 17,748 kg hydrogen * (18/2) --> about 159,732 kg of water, or 160 metric tons of water, assuming complete combustion.
The water would be formed as a vapor as the combustion temperature would have far exceeded the boiling point of water. As it would cool in the atmosphere, it could condense and fall as rain, but over a greater area than just the airport.
Here is a comparison in sizes of the Hindenburg to a Boeing 747, and the Titanic from the link above. It kind of puts the name "airship" into perspective.
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.ciderpresspottery.com%2FZLA%2Fgreatzeps%2Fgerman%2FHind_size.jpg&hash=4a977d59f016549a72fe0d7e18b619eb)
-
I obtained my figures from somewhat different sources and made it 161820Kg, there was also diesel oil and structual materiel burning that would also have provided water vapour
PS I think you made an error converting cubic feet to cubic meters !
-
PS I think you made an error converting cubic feet to cubic meters !
That's what I get for cutting and pasting (source above). I see the article lists both 7,063,000 cu. feet and 7,062,000 cubic feet.
Anyway, we're somewhere on the order of 160 metric tons of water. If the hydrogen was slightly pressurized, it would have been slightly more. Or, perhaps they would choose to run it with a slight vacuum (which would prevent building up a pressure differential as the vessel climbed).
-
I think the figure quoted in the German source was 200,000m3 and it was then converted to feet^3, I made the same mistake and converted meters to yards and forgot to cube the result (thats why we need proof readers !).
There where two more under construction at the start of the war but they were scrapped as an aluminium source.
-
It indicates that the Hindenburg produced about 242 tons of gross lift which is pretty extraordinary.
Consider the B-29 super-fortress had a carrying capacity of about 6 tons of bombs (plus fuel), with a total capacity of about 30 tons fuel and payload.
But, unfortunately blimps wouldn't be very practical for wartime airships.
-
I feel it is a bit demeaning to refer to the Hindenburg as a blimp which is a much inferior type of vehicle
-
I feel it is a bit demeaning to refer to the Hindenburg as a blimp which is a much inferior type of vehicle
Nonetheless, during WWII, there would have been benefits of lighter than air vehicles with minimal radar signatures, rather than a radar signature like the titanic floating in the air.
Construction techniques would be largely determined by the size and capacities. A non-rigid structure might have been incapable of hundreds of tons of lift.
-
That image comparing the Hindenburg, a Boeing and the Titanic is extraordinary; I had absolutely no idea it was that big - is that picture accurate and to scale etc?
-
That image comparing the Hindenburg, a Boeing and the Titanic is extraordinary; I had absolutely no idea it was that big - is that picture accurate and to scale etc?
I think it is supposed to be to scale.
The Hindenburg was supposed to be 804 feet long.
The Titanic was 882.5 feet long.
Boeing 747-100 to 747-400, 231' 10" long.
Boeing 747-8. 250' 2" long.
The Hindenburg is supposed to have about 242 Tons of gross lift.
This isn't too different from the Boeing 747 with about a 200 ton capacity (including fuel).
However, the method for generating the lift is vastly different between the two. And, thus one would expect the Hindenburg to be much larger in size than the Boeing 747.
-
That image comparing the Hindenburg, a Boeing and the Titanic is extraordinary; I had absolutely no idea it was that big - is that picture accurate and to scale etc?
Yes it is. It was huge to say the least. 804 feet in length for 100 passengers.
This site is an excellent resource on dirigibles: http://www.airships.net/
Wikipedia has this image to show its scale.
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2Fthumb%2Fd%2Fdf%2FBuilding_and_ship_comparison2.svg%2F600px-Building_and_ship_comparison2.svg.png&hash=196c12e98f056371b0378f9d47547106)
By the way my uncle served on the Macon during WWII.
-
That image comparing the Hindenburg, a Boeing and the Titanic is extraordinary; I had absolutely no idea it was that big - is that picture accurate and to scale etc?
Yes it is. It was huge to say the least. 804 feet in length for 100 passengers.
This site is an excellent resource on dirigibles: http://www.airships.net/
Wikipedia has this image to show its scale.
By the way my uncle served on the Macon during WWII.
The Macon?
BTW I know some guys who served on the red tanker shown above (when she was the Jahre Viking) and even seasoned old sea-dogs found themselves amazed at the size of her. She could move half a million tonnes of crude around the world at 15 mph - at today's prices that's around 400,000,000 dollars of crude!
-
Another question might be how much less lift the Hindenburg would have had if it had used Helium as a lifting gas rather than hydrogen.
Helium has an atomic weight of 4.
Hydrogen forms a dimer, and has a molecular weight of 2.
So, the helium weighs twice as much as the hydrogen.
If the Hindenburg had about 17 metric tons of Hydrogen and 232 metric tons of gross lift.
Then with helium, it would have taken about 34 tons of helium, and about 215 metric tons of gross lift.
Which still isn't bad.
If only Germany had a good cheap source of helium in 1936.
-
By the way my uncle served on the Macon during WWII.
Allen - maybe prior to WWII. The USS Macon (airship) was totaled in 1935.