"Airlander". Here we go again

[Tourist]

Originally Posted by n5296s

I think I have a pretty decent rough idea.

Your answer would suggest not.

As a man who has spent more hours than I care to remember orbiting above patches of desert day after day, trust me when I say that Airlander, if it works, has a hugely successful future ahead in military service.


Normal military aircraft are optimised for roles against countries that have some form of capability to fight back and require travel to get there. They do it well.
Against countries/people like the ones we have been fighting recently, and some we are still fighting today, they are a staggeringly expensive way of fighting a war. I'm not saying we don't still need the capability because they are absolutely critical, but offloading the hour intensive orbiting roles is hugely beneficial.
Reaper/Pred is an example of the need. They are in no way survivable against even an elementary air threat, but against ISIS etc they are perfect due to their endurance despite their slow speed.

[PersonFromPorlock]

FWIW, I seem to recall an article in a popular technology magazine sometime back in the '60s about a similar tri-hulled dirigible being built in New Jersey(?), whose stated purpose was to distribute Bibles in Africa! Later, the authorities stepped in and charged the promoters with fraud.

[Wirbelsturm]

presumably because they prefer to spend their money on things that go faster

Or perhaps it's because the US military has historically pursued multiple parallel lines of development and it was the budget constraints that cut the project rather than it's viability.

JSTARs was well advanced but also costs far more to operate, a helicopter is also expensive for middleman ops and less endurance, AWACS has been going for years now (since I was in the sandpit!) and is a costly HVU.

This design is cheap (comparatively), scalable, can be autonomous and can loiter for a long period when needed. Perhaps the US military couldn't run the full development program but I wish the current owners well.

[Mechta]

I had the opportunity to talk to Roger Munk before his untimely death. He said that he had attended a lecture in the late 1960s or early 1970s, by a First World War 'blimp' pilot, and had chatted to him afterwards. The blimp pilot had written on a napkin the ten issues which he believed would need to be overcome before airships became a practical proposition. Roger Munk then set about tackling each of these issues in his successive designs.

What the Airlander does which previous designs did not, is to generate a significant amount of lift from firstly, vectored thrust, and secondly, once airborne,
the shape of the envelope (hence the double bubble shape). This overcomes the loading/unloading issues cwatters describes, and allows a much smaller vehicle for the same payload.

As flown in the USA, the engines used were well below the power of the original spec. and only allowed a limited degree of thrust vectoring. With the right engines, which will allow Airlander to realize its full potential, I think they will be onto a winner.

[Vinnie Boombatz]

Story from last May, with fair amount of detail and photos:

Hybrid Hopes: An Inside Look At The Airlander 10 Airship | Production-Ready Solutions for Aerospace content from Aviation Week

Company site:

Hybrid Air Vehicles - Home

[Chronus]

By whatever name it goes, when all said and done it is a helium balloon by any other name. That which keeps it aloft is helium and the curious thing about helium is we are told we are running out of it. Here is a link to the bit about running out of it:

https://www.quora.com/Are-we-really-...-out-of-helium

Do these chaps at Hybrid know something that these other folk, who fear we are running out of the stuff, don`t know about so that they can blow their balloon up with 1.34 m cu.ft. of some kind of stuff to get it off the ground.

[TWT]

Commercial quantities of helium are extracted by fractional distillation from natural gas.There's a large plant in Qatar,for example.

http://www.rasgas.com/Operations/Ras...umProject.html

[enola-gay]

Helium

Chronus

That article says "Once it is released into the atmosphere it [helium] becomes uneconomical to recapture it". That is simply not true.

Helium is recovered from the atmosphere in industrial quantities as a by-product of cryogenic air separation plants whose main purpose is to produce gaseous or liquefied oxygen and nitrogen.

It is a high value by-product and far from unecomical. I worked with BOC in the 60s, and there was always a mini plant at each basic oxygen process steelworks to extract argon, helium, neon, xenon and krypton from the atmosphere. The atmospheric carbon dioxide though, was discharged as waste.

[Wageslave]

Originally Posted by Chronus

Do these chaps at Hybrid know something that these other folk, who fear we are running out of the stuff, don`t know about so that they can blow their balloon up with 1.34 m cu.ft. of some kind of stuff to get it off the ground.

There is a considerable difference between "running out" and "run out".
One means there is none left at all, the other means there is merely less than we might wish for.
Sometimes one may think that an understanding of proportion is "running out" on this forum.

[Landroger]

Chronus and Helium

By whatever name it goes, when all said and done it is a helium balloon by any other name. That which keeps it aloft is helium and the curious thing about helium is we are told we are running out of it. Here is a link to the bit about running out of it:

https://www.quora.com/Are-we-really-...-out-of-helium

Do these chaps at Hybrid know something that these other folk, who fear we are running out of the stuff, don`t know about so that they can blow their balloon up with 1.34 m cu.ft. of some kind of stuff to get it off the ground.

I can't do the sums quickly (or at all to be honest!) but Chronus is right - we are 'running out' of Helium, although not overnight, so to speak.

1.4 million cu/ft of Helium is a lot, but not if you liquify it and that is where the serious use of Helium is; LHe for MRI Scanners. Magnetic Resonance Imagers. When I first started working on them in the early nineties, a 500 litre LHe transfill was required about twice or three times a year, for each 1.5 Tesla magnet. There were not so many of them then, but there are loads of them now and almost every DGH has one (or more!).

Through development, Helium losses have been reduced dramatically to roughly one 500 litre transfill every couple of years, but the costs are roughly the same as they were. The last time I heard a price for it, given that we used tens of thousands of Litres per year, was about £5.50/litre delivered. For small quantities I have heard prices of £100/lt. The thing about liquid Helium is; it boils locally at minus silly degrees and changes phase into seven hundred times its volume. In other words, one litre of liquid Helium becomes 700 lt of gaseous helium.

Massive efforts are being made to reduce the overall liquid content of MRI magnets - this cannot be done retrospectively - from up to 2000 lt to less than 200 lt. Research is also being done into 'High Temperature Superconductors', which would be better, but it is rather flying in the face of the laws of physics at the moment. They have made materials that will superconduct at say, liquid Nitrogen temperatures, but it cannot yet be formed into any material that could be wound into a solenoid.

Several times in the last few years - I have been retired since July - there have been severe shortages of LHe, such that we had to wait several weeks for individual tankers to arrive from Morocco. As for 'making Helium' out of the atmosphere, we were always told that once He gets out, it goes straight up, does not pass go and collects almost nowhere and thus is very, very difficult to recover. The source of He is from Natural Gas and Oil deposits, it is or was, a by product. In the 1930's the US oil industry had to put silencers on the reservoir helium vents, there was so much coming out and being vented to atmosphere.

The plant that supplied us had 'a gas bag' into which each and every container, be it cylinder of gas or dewar of liquids, was vented when they were 'empty'. This 'dirty gas' was reliquified at the plant and reused, but they couldn't (and don't anywhere) distill it out of the air, because its already at the very top of the atmosphere.

Sorry to get technical.

Landroger

[Tourist]

https://www.newscientist.com/blogs/s...riticised.html

The Feds Created a Helium Problem That's Screwing Science | WIRED

[16024]

I was thinking the same thing about helium being a finite resource, and I am suitably impressed by the knowledge provided by the above posters.
Hydrogen used to be the buoyancy gas of choice, and it is relatively simple to make, but the flammability issues, of course are too much of a problem.
I do wonder, though, if some kind of Hydrogen/Helium hybrid could be made to work. There must be a safe dilution at some point.
I cant be the first person to suggest this, so I'm sure somebody can put the idea straight.

[Tourist]

Originally Posted by 16024

Hydrogen used to be the buoyancy gas of choice, and it is relatively simple to make, but the flammability issues, of course are too much of a problem.

Why should flammability be a problem?
After all, our current methods of flying around the sky also have a flammability issue.....

[FlightlessParrot]

Why should flammability be a problem?

Indeed. How many of the airship losses were caused by the hydrogen catching fire? I'm no expert on airships, but I can only think of the Hindenberg--the others being weather related. But there were the shootdowns, which is relevant for military use: but even then, I get the impression that a big bag of hydrogen was surprisingly hard to ignite with WW I weapons.

[16024]

After all, our current methods of flying around the sky also have a flammability issue.....

Well, it's kind of relative. Sure Jet fuel will burn under the right (or wrong..) circumstances, else we wouldn't get off the ground. But you can put your ciggie out in the stuff.

Hydrogen, on the other hand. Well, Hindenburg.

[16024]

My post crossed with that of FP.

Hindenburg may be one of the few where fire was the sole cause, but there were dozens involving fire resulting from some other cause.
I realise fire in a "conventional" aircraft is potentially disastrous, but it's a different ball game with a bag of explosive gas.
That's why they stopped using it.

[Tourist]

Originally Posted by 16024

I realise fire in a "conventional" aircraft is potentially disastrous, but it's a different ball game with a bag of explosive gas.
That's why they stopped using it.

Hmm, not really.
Google the problems with the Hindenburg. Heavier than air craft that catch fire have a similar problem to Hydrogen filled balloons.

It should not be difficult to google normal aircraft that have been lost to fire.

Aviation fuel is quite good at burning...
I can think of one very well known aircraft that burnt all too well.

[rse]

Yes, this is a bit revolutionary. Yeah, yeah, they said that about smartphones and Skype and the Internet.

Here we go again? Well, we need to give it a chance. Sure, it comes off the back of Airship Industries that put in a lot of R&D but didn't get visibly very far. They put in a lot of R&D because the technologies didn't exist 10 years ago to solve Munk's beermat list of issues: high strength skin, vectored thrust etc. This is only just possible now so we're right on the cusp.

It's not another white elephant airship remember: it's got a curved wing profile, vectored thrust, low docking point so it doesn't need a huge mast and landing gear that can blow in and out. It's also very compartmentalised and filled to very low pressure so you can hole it significantly and neither will it explode or deflate much.

The technology was destructively tested by the US Army who wouldn't have invested so much in it if it didn't have potential. Whilst Bruce could afford to lose his quarter mil, it's also been awarded a lot of green and regional funding that would only have gone to a worthy project.

Yes, you will need to get around the history of the word 'airship'. By all means give it a fair critique, but recall Concorde had plenty of doubters.

Yes, you will actually need to go to Cardington on the 'hard hat' hangar tour and ask the staff there as I did. Just join the club for life membership of £25 and sign up for a tour, they run them monthly and you get to ask what you like for 90 minutes. No question is off limits & nowhere else can you get up close to something this ambitious. They have a big, enthusiastic and capable team from all sorts of backgrounds who have done their sums.

True British innovation & I for one will be there when they roll it out in the spring.

[PDR1]

Hindenberg didn't crash due to a fire in the hydrogen. Hindenberg crashed due to a fire in the fabric covering, which was itself caused by a combination of poor electrical bonding or an access panel and the choice of red-oxide primer and powdered aluminium top coat in the nitro-cellulose dopes used on the fabric.

Sure, the hydrogen burned in the crash, but burning hydrogen didn't hurt anyone; the few of the casualties who got burned were actually caught in the fires from the ruptured engine fuel tanks.

You can see this in the film of the accident - the hydrogen flames have a distinctive colour and are all ABOVE the structure, whilst liquid fuel flames are much yellower, and fall down from the structure. You can also see moulten iron being spat from the burning fabric as the aluminium dust, iron oxide powder and nitrocellulose dope combined to create a classical thermite reaction.

The hydrogen burned in the crash, but it didn't cause it any more than the fireball of burning fuel that accompanies most tent-pegged aircraft was necessarily the cause of the tent-pegging.

For reference - the RAF operated a number of barrage balloons as part of the paratroop training process from the 1940s up until (IIRC) 1995. I vaguely recal they were based at RAF Hullavingdon (then a satellite field for RAF Lynham). These balloons were always hydrogen-filled because helium (a) gave less lift and payload, and (b) was simply unaffordable. They simply recognised the risks of using hydrogen and developed operating procedures to mitigate them. I don't *think* they ever had a hydrogen accident, but I could be wrong on that.

PDR

[Mechta]

For reference - the RAF operated a number of barrage balloons as part of the paratroop training process from the 1940s up until (IIRC) 1995. I vaguely recal they were based at RAF Hullavingdon (then a satellite field for RAF Lynham). These balloons were always hydrogen-filled because helium (a) gave less lift and payload, and (b) was simply unaffordable. They simply recognised the risks of using hydrogen and developed operating procedures to mitigate them. I don't *think* they ever had a hydrogen accident, but I could be wrong on that.

One reason the kite balloons used hydrogen, was that they were only inflated when needed; thus avoiding the need for expensive hangarage*. The technology used to ensure safe operation had been learned and passed on from when the Royal Aircraft Establishment at Farnborough was the Kite and Balloon Factory. Mechta Senior worked for the MOD(PE) auditing the various suppliers for the balloon equipment. A problem in later years was the non-static hemp rope of the right gradewas becoming unobtainable, as growing it was banned in the UK as it was considered a drug, whilst other parts of the EU received grants to grow it!

*Kite balloons for human parachuting were taken and inflated where needed. Some used for parachute testing were kept inflated at Cardington in the Airship hangars.

16024, I did ask the people at Hybrid Air Vehicles about using a non-flammable mix of hydrogen and helium. The view was that the hydrogen would migrate to the top of the envelope creating a more dangerous environment there. I also asked about an inner envelope full of hydrogen surrounded by the helium outer envelope. The problem here is that all the cabin/payload suspension cables would have to pass through it, creating sealing issues and extra weight, thus negating the benefits.