Looks strangely familiar to me...
The first rigid airship to be built since the 1930s is about to commence trials in California: and the Pelican prototype also features a new technology, never yet flown, which could finally change things for lighter-than-air craft and see the leviathans of the skies make a serious comeback at last. The 230ft-long, 18-ton …
Look at footage of the Hindenburg: it burns, sure, but there was no explosion. Hydrogen will only explode if mixed with an oxidiser (air or oxygen, usually) in the right proportion. Without the dodgy paint on the Hindenburg, I reckon than the fire and crash would have been much, much slower and more survivable. A healthy fraction of the passengers and crew survived anyway, albeit somewhat charred in most cases.
I do not mean that the airship actually exploded b/c it burned down rapidly. However, (iirc) the exploding mix has quite large tolerance 18-60% of hydrogen by volume. That's it, leakages might be prone to hazard, the ones that won't explode still would be prone to combustion.
And the only deaths were actually from people jumping or being burned alive by the fuel, none were killed by the hydrogen directly, or even the skin of the ship.. it fell slowly to the ground...
I wonder if it should be designed to burn up the hydrogen fast, but controlled, and then have an emergency parachute to lower the surviving vehicle to the ground slowly enough for survival....
When I was working around an oil refinery, hydrogen was considered a relatively safe gas -- it's so light that it escapes faster than it mixes with air. Something like ethylene (similar density to air) was considered much more dangerous.
That's not to say that it is as suitable for miliary airships as helium would be -- I seem to remember Biggles shooting down observation blimps.
A recent ??? documentary with an aeronautical engineer, familiar with Zepplin technology, stated that it was the excessively hard turn by the Captain, to help land the Hindenburg quickly by shortening the "coming around" and at the tethering mast, from down wind, that lead to excessive structural loadings, that snapped some of the wire trussing inside the framing, that slashed one or more of the sacks that held the hydrogen.
It was the hydrogen that leaked inside the airship that was assumed to have been ignited by static electricity that started the fire.
The paint, being composed of assorted compounds and layers, included iron oxide and aluminium flake, to which many people have claimed is a thermite mix, that made the fire accelerate along the exterior, while the membranous sewn up goat intestine bags that held the pure hydrogen, burned at an rather great rate of knots, far faster internally, than the skin did.
The exterior, while containing the compounds of thermite, were mixed and applied in a way to discharge static electricity, and reflect solar radiation and while capable of combustion, the compounds in the coating were not capable of burning in a "thermite" type of way.
The outcome was that it is plausible the skin was key to the way the Hindenberg went up, but it takes both the skin AND the hydrogen to get the disaster. Essentially the skin acts like a fast fuse while the hydrogen still provides the bulk of the explosive charge.
On Earth, yes!
It's so light, and unreactive that:
1) If there's any loose stuff, it escapes upwards and is gone
2) It doesn't exist as a compound of anything, so the only source is contained in a finite number of quickly depleting reservoirs.
Once it's gone, that's it until we learn how to bottle it somewhere in space.
It is rather rare on earth. And is the first to be blown off by the sun.
Hydrogen is lighter, but forms compounds that bind the hydrogen to the earth.
Hydrogen has twice the lifting capability (H2 molecules are nearly twice the volume, and only half the mass).
Personally, I would think a double bag system with carbon monoxide in the outer bag, and hydrogen in the inner bag would be just as safe as using helium. The CO could then bind to any leaking hydrogen (preventing combustion) and still provide 90% of the lift of hydrogen.
"Hydrogen has twice the lifting capability"
Nope, by that logic a vacuum chamber would have an infinite lifting capacity.
The lifting capability if the difference between gas density and air density. The molecular weights are:
i) Air: 29 (approx)
ii) Hydrogen: 2
iii) Helium: 4
So the hydrogen has an advantage of 27/29 to 25/29 (or 8% more). Hydrogen is lovely because it's dirt cheap, not super-floaty.
"Hydrogen has twice the lifting capability [of helium] (H2 molecules are nearly twice the volume, and only half the mass)."
1) The lifting capacity is the difference between the density of air and the density of the lifting gas.
Hydrogen: 1.293-0.0899= 1.2031 kg/m3
Helium: 1.293-0.1785= 1.1145 kg/m3
(at 1 bar, 0° C)
2) The volume of H2 molecules is irrelevant. The number of molecules present in equal volumes of gases at the same temperature and pressure are equal (Avogadro's principle).
...and one small leak in that CO envelope would render your ground crew dead from poisoning! Never mind the issues with refilling it with the stuff.
Helium = too rare and expensive
Hydrogen = too bloody flammable
Airships based on either = not a good idea.
Military applications? Multiple gas cells would be irrelevant against a single brief burst of cannon from a modern aircraft or gunship. Or perhaps one of them there anti-aircraft missiles?
> Personally, I would think a double bag system with carbon monoxide in the outer bag, and hydrogen in the inner > bag would be just as safe as using helium. The CO could then bind to any leaking hydrogen (preventing
> combustion) and still provide 90% of the lift of hydrogen.
There certainly could be no problem with this scheme?
It's rare down here at the bottom of a gravity well full of other gasses and water and monkeys and things. Hydrogen we can at least extract from the water, which is already down here with us. Helium doesn't hook up with other things, so it's not something we can extract from other stuff that's around, and once we let it leak away, it goes up to the top of the atmosphere and stays there until something blows it off.
"Hydrogen we can at least extract from the water, which is already down here with us"
Certainly hydrogen has some advantages. This whole "really flammable is a bad thing" idea is interesting, because on the same basis you wouldn't come up with designs where you fill an aircraft wing with highly flammable avtur, and then hang a nice hot, fast spinning gas turbine a few feet away.
Most of the Zeppelins lost in WW1 went up in smoke one way or another, the R101 left a big pile of ash, but only when the Hindenburg had the temerity to be caught on newsreel did it become an irresolvable problem. A bit like Concorde, which in a similar manner was acceptably safe until it wasn't, or the dodgy fuel lines on Nimrods.
Given progres in materials science, is it really impossible to produce a reasonably safe means of holding hydrogen in this application?.
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Probably not an issue with modern tech for a low impact civilian cargo shifter, but not ideal where people will be actively trying to make it not fly, by using tracer & incendiary ammuntion.
I would also be concerned that these are large, slow, and not particularly manuverable targets, so forward support might be a "bit risky", and the concept of "rear areas" has not been seen to exist for some time, hence the flying styles adopted by C-17, Hercs and Chinook pilots.
Low signature loitering radar platform for blue water surface combantants might work?
" imagine jabbing a knitting needle through a roll of bubble wrap"
Not many AA missiles depend on impact fuses, because you can't be sure of a direct hit - much easier to get within the warhead's destructive radius and detonate (in principle, think of the altitude fuses on anti-aircraft shells in war films (or reality, for that matter).
A payload of shrapnel detonated close to the airship will puncture enough cells to bring it down. I'm sure rockets or missiles can be modified to carry shrapnel. I don't see the point of this aircraft as it's too big, too slow, too vulnerable. Because of the load it can carry the loss of life and equipment if one was brought down would be huge.
" I'm sure rockets or missiles can be modified to carry shrapnel."
That's how the smaller ones work anyway - many years ago when I saw the stuff on things like this, they used stuff like big bike chains round the warhead, or a cylinder or cone of metal around the charge. On a larger SAM you could use a bigger explosive charge that would damage by blast alone, but even then you've got the residual bits of the missile itself as shrapnel.
However, the size of an airship ins't really material, because it is unlikely they'd carry more than a conventional transport aircraft already does.
" ...stuff like big bike chains round the warhead, or a cylinder or cone of metal around the charge... "
The concept you're looking for is "(expanding) continuous-rod warhead." Take a bunch of fairly ductile metal rods. Arrange them in a cylinder. Weld alternate adjacent end bits together, so the stack of rods becomes a continuous circuit, closely collapsed. Stick an explosive charge in the middle. Hang a rocket off one end and a proximity fuse off the other, and Voila! A modern AA missile!
The warhead detonation tends to turn the rods into a very large ring, violently expanding flying high-velocity ring. They do horrifying things to conventional aircraft - I suspect they'd do rather worse to lightly-hulled dirigibles. Hydrogen or no hydrogen.
I don't think it's supposed to be flying into the front lines. I think it's more likely for quickly moving larger forces and heavier equipment into secure locations after a safe air-corridor has been established by a the initial group of conventionally transported frontline troops.
Alternatively, if the _entire country_ is too hot for it, you put down in a supportive neighbouring region and roll over the border on the ground. The alleged strategic advantage remains that it is faster (and works in more places) than a carrier ship, and gives you better value for money than tying up conventional aircraft.
>A payload of shrapnel detonated close to the airship will puncture enough cells to bring it down.
Basically that principle was proven by the British fleet sailing to the Falklands and using artillery (low speed shells) against (high speed) aircraft.
However, as this is a rigid airship, there is the potential to use kevlar and associated composites to lend some protection to the air sacks.
But putting all this combat zone stuff to one side, any observation of recent major military deployments would reveal two important themes: Firstly supply lines have been very long (IUK-Falklands, USA-Iraq etc.) and requiring significant amounts of heavy lift by air, which is expensive and a logistical nightmare - even if you can get your hands on an Antonov. Secondly, the military has become involved in humanitarian & disaster relief work, where typically the infrastructure has been disrupted or destroyed and the need is either to ship stuff in and/or get large numbers of people out. I think in these circumstances a heavy lift airship becomes quite useful and hence something the military would want in their back pocket.
> If an airship was used to transport troops to take on a militarily capable country, surely it just presents a nice large slow moving target for a missile system to put a few holes in?
This is the primary reason they are no longer used.
This is an extract from Storm a biography of Irvin Crick. (The rain maker.)
In the early morning hours of April 4, 1933, Krick's habit of searching out fronts on weather maps involved him in an event which firmly set the course of his future.
With an early morning class at CalTech, Krick took a nap each night during the five hours of little flying activity when the IIO-miles-an-hour Fokker F-IOs flew from Salt Lake City to Las Vegas. As he turned in, he remarked to the radio operator, "I'm glad we're not flying off the coast of New Jersey tonight. There's a cold front coming down from the north-east and a warm front coming up from the south-west. When the two meet there is going to be one awful mix-up. It'll be very violent."
Krick was no sooner asleep than he was shaken awake by the radioman.
"My God, the Akron just went down in the Atlantic off Bamegat Light -right where you said all that rough weather was coming!" he exclaimed. The Akron was an enormous airship -78? feet long, large enough to accommodate five airplanes aboard. It was the pride of the United States Navy. Seventy-three men died in the disaster, the headline event of the day.
At school later in the morning Krick sought out Dr. Theodore von Karman. Known as "master of the wind" for his knowledge of fluid mechanics, this Hungarian-born scientist was chairman of CalTech's Guggenheim Aeronautics Laboratory, which later was to spawn the world-famous Jet Propulsion Laboratory. Von Karman also headed the Goodyear Airship Institute at Akron, Ohio.
"The Akron never had a chance," Krick said. "The wind shear set up by these two opposing air masses blowing in opposite directions was bound to destroy the ship. She should never have been flown into this kind of weather."
Von Karman was impressed by Krick's earnestness. "Get me the velocity of these winds and we'll calculate the stresses on the ship," von Karman told him.
The calculations, by Frank Wattendorf, Karman's assistant, proved Krick to be correct:
The Akron, broken in two like a stick across the knee of a giant, was doomed from the moment the ship left the hangar, although the United States Weather Bureau had reported that the storm posed no danger to flying that day.
So that is major problem #2 covered. Modern meteorology can help plan journeys of 5 days and get most aircraft out of harm's way any old three days ahead. I don't know what metal fatigue and electro-static problems still remain.
Problem 3 is the gas and containers
And a loooooong way behind is the ballast problem. There is always going to be a problem with trim, even the most modern submarines have the same thing to contend with. With aircraft yawing and etc., is part of the fun of flying and is compensated for by computers in larger craft.
"surely it just presents a nice large slow moving target for a missle system to put a few holes in?"
I can't see a close combat role for this thing, but for a modern AA missile any transport plane or helo is so slow as to be stationary, and in that respect an airship is a bigger target, but speed and manouvrability for anything other than a fast jet don't come into it - you have to avoid being shot at, or deploy countermeasures.
Even old tech hand held missiles like the thirty year old Stinger have speeds of 1,500 mph, compared to the circa 250 mph of a transport aircraft at low alititude, a speed differential of 600 yards a second, if the missile is fired after the aircraft. Cruising speed at higher altitude of a C130J is still only 400 mph, and at those altitudes (unless you're attacking people armed with nothing more advanced than Russian, Chinese or Iranian Stinger- equivalent) you're facing more advanced longer range mssiles moving at speeds of 5,000 mph, a speed differential of more than a mile a second.
Obviously transport aircraft and helos can hide in the terrain and an airship can't, but as we've repeatedly found that doesn't make them invulnerable, and adds risks of its own. A more pressing limitation is the combination of size, acceleration, maouevrability, and load, which is likely to favour helicopters, although it is notable that 32 Chinooks have been lost in Afghanistan, about half of them to enemy fire, and a large proportion of the remainder due to operating to avoid enemy fire (so low flying, unfavourable landing conditions).
The main competitor for the military airship is the carrier group, which usually includes an amphib carrier with lots of transport choppers. Whilst the majority of the World's trouble spots are within range of choppers from off-shore carrier groups the idea is really moot, and you have to wonder how it manages to scrape through the budget meetings. The only reason I can see is the usual inter-service rivalries.
".....the COSH gear aboard the new ship can vary the 36,000lb (16,329kg) ship's weight by about 10 per cent....." 3,600Lbs is not much of a payload, it's within that of even the smaller transport choppers. The CH-53E Super Stallion, typically what the Yanks use from their amphib carriers, has a useful load of 32,000Lbs and is based on an over forty-year-old design. The tilt-rotor V-22 Osprey can manage 20,000Lbs and has many of the range and speed advantages of traditional cargo planes.
".....British forces have not conducted a combat parachute drop since the 1950s...." But even the Brits have conducted helicopter assaults, because the helicopter is a more flexible and cheaper tool. Even should the airship idea actually be made to work, the very cost of will mean the idea of owning more than a dozen will be unlikely when the chopper can do 90% of the missions required. At best, the airship will be relegated to the role of second wave transport, after the choppers have secured the landing zone, and in the short time before a strip is cleared for transport planes.
As a cargo carrier it certainly doesn't look that useful.
But rather more interesting as a development project if (rather than for cargo) is actually towards unmanned weapons or surveillance platforms, capable of staying on station for weeks at a time.
Against a capable adversary with modern air power they would be very vulnerable, but in the wars of choice that are typically fought these days they could be very useful, and for example in cold war monitoring of naval traffic. Potentially they could be used for AWACS, being hardly much more vulnerable than a lumbering 707 airframe, where you need several aircraft (multiple AWACS plus tankers) to give continuous cover.
I like it better for delivering large amounts of cargo to remote, unimproved sites where there is no likely prospect of a landing field, and where helos are range-probibited.
Probably be damned useful in logging, too - no need to cut roads in or out - deliver the loggers vertically, remove cut trees the same way.
Wilderness firefighting? Possibly as a high-endurance on-scene incident controller? Has possibilies.
Fisheries surveilance, enforcement, support, and survey? Yup.
Poor-man's satelite? Why not?
So - I see uses. Whether they're *economic* uses remains to be seen.
"Probably be damned useful in logging, too - no need to cut roads in or out - deliver the loggers vertically, remove cut trees the same way."
This principle is used in several locations worldwide, although the gasbags are usually tethered to a couple of adjacent ridges and loggers usually walk in.
There are a bunch of civil applications where airships would be tremendously useful, as long as kept clear of bad weather - and if unmanned they can be flown "above the weather" for months at a time. Even for military use the Walrus concept has a lot going for it logistically as long as it's kept out of hostile areas. (Ok, so it takes time to pump down the gas, just unload at a slower rate - or use more pumps.)
Hydrogen has a few more issues than just its flamabilty - apart from the metal embrittlement issues it does much the same thing to gasbag materials too (fill a kids' ballon with the stuff, leave a few days, then deflate to see what I mean)
Completely unsuitable for wilderness firefighting: large fires create huge thermals and very strong turbulent winds, and can also generate lightning and fire tornadoes. In other words, even the largest airship won't cope with the 'weather' created by a large fire. Here is some El Reg reporting on the subject: http://www.theregister.co.uk/2012/11/21/australian_fire_tornado/
The cost effectiveness of the ships is the controlling factor here. Cost and maintenance of a large helicopter is huge. Fuel efficiency is very low.
Airships are likely to scale the way liners and oil tankers do, the bigger, the better.
The only problem is that they would need their own air force to protect them.
(Which would make them about even -except that if you had a fleet of airships you would have at least 1 spare air-force to play with when not invading Norway.)
Yep, the CH53 needs 44 hours of maintenance per hour of flying time, while Ospreys and Chinooks are around 10:1.
If an airship can get down to half that, and they scale up to carry a decent payload, then there is a definite market.
The other thing is I can see them being incredibly useful for is disaster relief. Flooding, tsunami wreckage, anything large scale and requiring rough field capability. Especially since a lot of disaster relief gear is bulky but relatively lightweight - foodstuffs, shelters etc. Water, not so much, but win some lose some.
Also, things like mobile medical facilities - a decent surgical suite is relatively light, and if backed up by helicopters for medivac to offfshore units for severe cases - drop the airship down into a clearing, anchor it in place, and easy to move on once the need is finished.
I think the military transport role is pretty much a white elephant, but things like long term surveillance, maritime patrol or S&R are all viable use cases if they can solve the payload issue, as they play to an airships strengths.
Airships are also incredibly useful for situations where the need to spend a LOT of time in the area is paramount. Their speeds are enough that they can keep station in almost any weather, they're fairly quiet as flying things go, and they can get in close to places because they can move very slowly. And once there, they can hang around for DAYS, not mere hours. You might not even need to land that surgical suite; just winch up patients, treat, and winch them back down for post-op care where they are and move the suite on to the next site.
>> Using an air tank that can be compressed (rather than helium) would allow for a larger weight change with less chance of losing expensive helium.
That sounds rather more sensible, suck the outside air on-board and compress it into tanks to take on weight. The surrounding air is also full of moisture unless you're over a cloudless desert and this could be taken on-board too.
I presume that is part of the COSH design
a single cell is made of a rigid material with an inner membrane like a sac. filled with Helium.
to take on mass, the helium is sucked in and compressed, with outside air (outside the protective sac) filling the space ... thus negating helium loss and also avoiding a vacuum in the cell, also the incoming air adding more mass.
I imagine that'd be a scary ass noise, hundreds of vents hissing out air on ascent ... :)
"That sounds rather more sensible, suck the outside air on-board and compress it into tanks to take on weight."
Sure, but how much fuel are you going to use to do the compressing, and how much weight will you lose from burning off said fuel in the process?
Unless you can do some kind of reclamation or you use solar power (which, given the situation, might not be too impossible...) my guess is that you'll still end up losing a bit of weight. Can anyone with more than a hunch answer that question for real?
I can see niche markets.
Tourism / air 'cruises'
Delivering cargo to very remote locations with no landing strips (e.g. some nature reserve in middle of Congo or Amazon)
But I don't see any military uses, certainly not in terms of flying into war zones. They're big, slow and fly at low altitude. I'd sooner risk a parachute jump and take my chances on the way out.
My grandfather served on an LST in the pacific, and was the first one to tell me the 'LST' thing. He had some pretty awesome stories - I guess he didn't tell me the other kind.
One of them was that he (IIRC, maybe it was a friend of his) and a buddy were ordered to paint the first mate's office; the mate saw the work and was pissed because they missed some parts. So he yells, "When I say the office, I mean THE WHOLE OFFICE!" ...so my grandpa and his buddy painted the whole office: Walls, ceiling, floor, desk, paperwork, windows, chair...
I wish I'd tape recorded more of our conversations. And with my great uncle, too, who was in a tank battalion in Europe... apparently tanks were a really bad gig. I hope someone out there is interviewing the vets 'for real'; it would be a shame if the main legacy of WWII troops is 900 hours of low-rent History channel 'air battle' documentaries...
"apparently tanks were a really bad gig."
Think "Cannon fodder" - The germans used to call Shermans "Tommy cookers". Horrifically vulnerable to a shot from the side and the front armour wasn't up to a close shot from panzers or tigers either.
The only advantage they had was that there were a shitload more of them than there were Tigers or Panzers, so the Allies could "afford" to lose 10-20 Shermans per German tank destroyed (There were a few Churchills in service but they were mostly obselete and converted to "funnies" (mineflailers, bridgelayers, etc) well before D Day.)
War by attrition is the kind of thinking which in earlier years brought us events like the battle of the Somme.
Even with the numerical advantage, what really put the german tank divisions out of action was the sucess of allied attacks on axis logistics - a tank can't go far with no fuel.
about the parachute assault on Dien Bien Phu - Operation Castor. It worked perfectly with the exception of the first bulldozer slipping its parachute harness and free falling most of the way to the ground so delaying the opening of the runway by a few days. It was the rest of the plan - Operation Pollux - that went pear shaped.
Seriously doubt a ludicrous boys toy like this would have made any difference other than giving the Viet Minh AA gunners something else to shoot down.
Besides, Operation Market Garden was not a complete failure. It did not achieve all the objectives, and Arnhem was indeed a bridge too far. The bridges over the Waal and Maas rivers were captured intact, by paratroops. The southern half of the Netherlands (including me mum and her family, who lived in Nijmegen at the time) were liberated much earlier than the rest of the Netherlands, thanks to Market Garden.
".....Operation Market Garden was not a complete failure....." True, but that one bridge too far left a lot of paras stuck in the brown stuff with very little option for extraction. I'm not sure a blimp would have made much difference, it would present too big a target, but helicopters would definitely have allowed extraction if they had've been developed at the time. I think Lewis's contention that an airship or airships would allow a large ground force to be extracted better than existing means is debatable. It might have a point with a longer range insertion of heavy kit, but only at considerable risk to the heavy kit in that a blimp makes an awfully easy target to shoot down, even with conventional artillery.
The paratroops that dropped on the tank battalion were shot out of the sky. The egyptians did exactly the same thing to us when they took over the canal there. Hitler stopped the parachute attacks after the problems in (was it) Crete?
It was obvious that they were completely at the mercy of anyone below them if the home side was prepared. None has ever come up with a solution. But if you were a looong way behind enemy lines and had a night operation planned, you could successfully land an army with a few large airships.
An army that would be seen coming, quickly surrounded and have very little chance of surprise in the first place and no hope of supply or rescue in the second.
It isn't a military solution. But it should be a military project. Otherwise civilians will never reinvent it.
Pumping the helium into a container on its own wouldn't suffice. If the gas cells are rigid, then the helium needs to be replaced with some other gas, else you'd create a vacuum, which at the least wouldn't reduce buoyancy. Also, replacing the pumped out helium with some other gas (like normal air) is not a good idea, either, since then if you'd want to increase buoyancy again afterwards, siphoning out the air without also removing some of the expensive helium would not be easy - they won't be that cleanly separated.
My guess would be that they have internal helium cells that they can decrease in size as required to control buoyancy, without actually moving the helium from the cell into some container.
Still, this needs to be a very fast system, unless they only want to be able to load/unload small items one at a time.
Good point. Increasing the size of the airbag would also reduce the space available for the helium, so no need to reduce the volume of the cell. (I was remembering when I built a model airship, filling the thing with helium is difficult when using rigid cells. Needs to be done very slowly, else too much air remains mixed with the helium)
Maintaining the shape of the airship is not due to the helium, though. You'd normally have some kind of outer hull.
I'm not sure old airships had a "greatest" weakness. They were all slow, unmanoevrable, fragile, had limited lifting capacity, and being highly flammable was icing on a rather unsavoury cake. A quick gander at the Wiki article on WW1 Zeppelins shows that as many were lost to weather as defensive action. Even if filled with helium, then the tactic of dropping bombs on them would probably have brought them down through loss of buoyancy.
We've still yet to see that with modern design the airframe is strong enough to survive the weather, the propulsion capable of controlling the vessel, and the buoyancy systems able to keep the aircraft aloft if all operating conditions.
Not so useful, I'd guess, because the payload is so small relative to the size of the vehicle.
A single C130 has a max payload of twenty tonnes. or 130 combat troops, and to get that from an airship you're talking of a 500+ foot long vessel, which might have low fuel costs, but won't come cheap in terms of construction costs. And by the time you've built the facilities to safely operate a vessel of that scale you might as well have built a rough strip for the C130. (with parking to allow you to land and park five or six at a time).
There might be a future for airships, but it needs to be a much higher value add task than transporting a handful of troops in undefended territory.
Death by helium asphyxiation is the top recommended method in the alt.suicide.holiday faq-file. Simply get a canister of helium, rig up some breathing apparatus so that you are breathing almost pure helium. You get none of the 'omg I'm suffocating' gag reflex, since that is actually due to the build up of CO₂ in the blood, and you gradually lose consciousness as you lose oxygen in the blood. After about 20 minutes or so, you've had a comfortable, pain free death,
Downsides are that if discovered 'in time', you've typically suffered brain damage. Lots of it.
The other suicide method that has intrigued me is slashing the wrists and bleeding out in a warm bath, as favoured by the Romans, who saw 'patriotic suicide' as a way of dying with dignity in an impossible situation, eg Cato the Younger, who disembowelled himself - ripping out his own intestines rather than let a doctor tend him - rather than live under the despot Caesar.
I actually mentioned it in the original post - alt.suicide.holiday FAQ.
It's not a monthly publication, somehow people only wanted the one issue, and after that all their mail was returned...
And it is quite interesting. Suicide was never 'sinful' until the god botherers got the idea that part of you - the soul - isn't yours, it's part of a cosmic godhood that you are just renting, and don't do anything bad with, or you go to the hot place. Greeks and Romans viewed suicide very differently.
There are lots of different methods documented in the FAQ, some are crazily efficient, some are crazily inefficient, and most suicide attempts use the inefficient ones - either they don't know better, or they don't really want to die.
Eg, hanging, you can hang yourself quite easily - and asphyxiate to death with a crushed windpipe. It's excruciatingly painful, and if discovered before you pop your clogs, unlikely to work. Alternatively, buy the right rope, tie the right knots, fall the right distance for your weight, and your neck will snap instantly, with almost no chance of failure.
"Cato the Younger, who disembowelled himself - ripping out his own intestines rather than let a doctor tend him - rather than live under the despot Caesar."
You know, I crave liberty as much as the next guy, but I think I'd pick 'Live in comfort and wealth under the despot' over 'Die a slow, agonizing death in exchange for mad post-mortem street cred and a guaranteed spot on the Wikipedia 'notoriety' list'.
Shear stresses brought about by opposing storm cells.
Quite a problem without satellite surveillance.
Easy to shoot down by AAM.
More so than you might think. In WWII Zepplins were the terror weapon. Machine gun fire did not down them because they make very small holes in a very big skin. It was when both sides switched to tracer rounds and ignited the H2 that they started to drop.
And a dirigable would make quite a gunship.
One of the less appreciated things about airship operations was (AFAIK) that they had no flight simulators for pilots to practice on.
Keep in mind that a truck tire is also an "inflatable gas bag" and tires on carrier aircraft can run into the 100s of psi. So building a lightweight pressure sphere (best shape for high pressure) which does not have to be weather proof (as it's inside the body) should not be too difficult for say 10 atmospheres. Likewise using membranes to separate toxic propellants from driver gases which might dissolve in them is known in the pressure fed rocket field. Making lightweight highly impermeable gas tight membranes is well within the SoA. So using the same bags for air and Helium (on opposite sides of the membrane) is certainly possible and expelling the air should be quite fast.
The question is how big (and how heavy) a compressor do you need to get the responsiveness of the process to work?
I think their is huge potential for this. Imagine floating at near zero speed and watching Eagles or Falcons circling it the way dolphins follow ships.
Another problem with WWI Zeppelins for the Allies was the height at which they flew compared to the wood, linen and wire aircraft of the time.
An Airco DH2 in 1915 took about 25 minutes to reach 5,000 ft. In the time it took to achieve an interception, the Zepppelin could have unloaded its bombs and be flying - even higher - for home.
As anti-submarine patrols, the British put a lot of non-rigid airships into the air. How about using an airship to as escort shipping in pirate zones.
"As anti-submarine patrols, the British put a lot of non-rigid airships into the air. How about using an airship to as escort shipping in pirate zones."
ASW has been a running theme of US Navy work.
People keep thinking what a huge radar scanner you can skin inside the envelope without turning it into a fuel hog.
Naval early warning aircraft for those 'this week it's vertical takeoff only' QE class aircraft carriers? Like a 'copter, but can go higher and has massively greater endurance.
If the baddies can shoot it down if its 10,000ft above the carrier, then your CAP's failed and the carrier is then not going to be a lot safer, is it?
Surely the idea here is that it would not be flown into a warzone? I'm not convinced they are trying to create it to fly into active warzones where they do not already hold the air. Take the Iraq war as an example, within 1-2 days of the conflict there was little/no threat of planes being shot down (although it did still happen, didn't it). Given the load something like this could hold, landing even close to where you'd like to be will still be a better idea than trying to get everything in using conventional planes (Considering cost/how much this can move) i'd have thought.
If it's largely hardware (vehicles, etc) then it can move on it's own after you land, if not and it's equipment then it's just loaded up and moved after landing via vehicles. I'm not convinced you'd even bother trying to fly something like a C130 into an active warzone where you don't already hold air dominance so i don't see this as being much different really.
If your against an opponent who has a reasonable air force/surface-air defence, i don't think this is "that" much more vulnerable than any cargo plane and if you are going to fly it over SAMs, etc then you deserve to have it shot down.
Just what i reckon...
And it is essentially that the strength to weight of available materials limits their size if they are to handle anything more than quiet air conditions.
Even carbon fibre wont substantially make a large airship capable of carrying a decent load, feasible.
There may be a very small niche market - as the Goodyear blimps have exploited - for the ability to remain stationary for long periods. But its a very small one.
Helium? If only Bill Clinton had not sold off the massive Strategic Helium Reserve in the late 90s this would be a zero-cost option. I wonder what we now use the big underground caverns the helium was kept in for?
Also: Military gasbags? Strikes me this is not only a double entendre but more importantly a stupid idea waiting to be demonstrated. If I have the facts straight, military sites needing emergency supply have these things called "bullets" zooming around. Military "bullets" are designed to go right through a human being (the bods that drew up Geneva Convention believing this was less cruel than having the "bullets" lodge inside a soldier apparently). I imagine the so-called parabellum "bullets" would have no trouble whatsoever in riddling the internal gas-cells of this machine, making the lift/ballast question moot as the entire ship became what we call a "frame tent" (albeit a leaky on thanks to the holes punched in it by the "bullets").
Also also: Helium diffuses out of most expanding rubber-like materials very quickly as every kid who has been given a fairground balloon knows. This idea of pumping it around in bike tyres seems to be uninformed wrt the ugly facts.
Also also also: For all the hoo-ha about Hydrogen's dangerousness when compared to Helium, it provides twice the lift for a given volume of gas. Have any kind of studies been done on the weight of fire mitigation tech vs half-the-lift, or are we firmly in the land of the No Nuke mentality here?
Also also also also: Airships suffer from a problem specific to the mode of lift generation, namely that the air density upon which the local lift depends can vary suddenly with no warning, and it can do so non-homogeneously over the length of the envelope, all of which is part of the lifting structure (unlike a conventional aeroplane). Airships of old were *extremely* vulnerable to this problem - irrespective of the lift gas chosen - because of their enormous length and the fact that the sun shining or not on bits of the envelope can locally heat or cool the lift gas and cause it to change its lift properties.
These craft are only meta-stable at the best of times. Submarines have similar issues but their medium and buoyancy techniques have the advantage that changes introduced are usually fairly slow affairs, easy to correct for in the comparatively dense medium of the sea. Not so with airships that can move quite quickly through the air in any direction should the conditions change.
There's a rather neat eyewitness account from the control gondola of an airship launch in the January 1925 issue of National Geographic that demonstrates that even with a crack crew and officers who knew what they were doing, something so "simple" as casting off from the mooring mast was an operation fraught with complications. I recommend it to all.
It's maximum lift is the density of the air at sea level.
The idea is employed in the "The Diamond Age."
The problem is that air pressure is surprisingly strong when it's not balanced.
As the container gets bigger the surface area over which it acts (on the container) gets bigger.
Looks great, but if it works out then I expect a sudden uptick in flying saucer sightings. Several points follow:
Regarding capturing water from the engine exhaust for use as extra ballast, wouldn't it be easier to just capture it from the surrounding air using a condenser of some sort, rather than adding something to the exhaust system that might affect engine performance? Then again, I guess a condenser for external air could be weighty, and would probably not work well in very dry environments, whereas the engine exhaust would always have a certain amount of water in it from byproducts of combusting hydrocarbons.
Agree with previous posters that a hydrogen-based airship would probably not work very well in a military environment. Helium could be bad enough if someone was shooting at the airship and hit the ballast system.
Something like this ship might work beyond the military for extraction of lumber from remote areas, which is sometimes done by helicopter now. Maybe even airlifting agricultural produce like coffee beans, or precious metals/ores from remote sites?
I'm the first to concede I ain't no combat veteran. H3ll, I wasn't even combat-arms. So my opinion is light in the balance. But the idea of being transported anywhere-- but especially into action-- with something covered with...fabric...any kind of fabric...no matter how high-tech, in my opinion...and virtually hollow...is A Really Bad Idea...and frightening to the core.
The sad thing is, I know The Puzzle Palace isn't kidding. Some wingnut, uniformed or otherwise, there actually thinks this is a concept worth millions of dollars of investigation if not R&D. And moreover, said wingnut even has found people more authoritative to rubber-stamp the deal!
All the Helium on planet Earth comes from a single mine in Delhart, Texas...
The US Congress in 2011 released the strategic hold on the reserve...
Enabling this harebrained project and ensuring the end of commercial Helium...
Like we need more kinds of spy in the sky equipment, that uses irreplaceable stuff...
Best use for these things is un-manned, with Hydrogen lift gas...( WW2 barrage balloons )...
Let them be blown up occasionally by enemy ground fire...save the Helium...RS
Try reading Dean Ing's _The Heavy Lifters_ for a more advanced (imo) and larger rigid airship with more utility- dynamic ballonets for balance- though military use would be rather dumb [or desperate] unless you had more than your payload in point defense! (BTW, bigger can really be better with Lighter Than Air designs)
(for a taste of possible why's, try the same author's _Systemic Shock_ [and keep reading, it's the first of a trilogy! ])
Another possible COSH method can be found in S. M. Stirling's _On the Oceans of Eternity_, [2004, 3rd book in that trilogy] where they use a fixed set of lifting gas bags, and a section that's a variable lift hot air balloon. granted, it's a tricky bit of engineering- but they were working with limited amounts of tech hardware, albeit with knowledge of 20th century tech.
both concepts use the simple idea of neutral-density fuel gases so running the engines doesn't affect static lift. (yes, that does make for low-energy-density fuels, but there are always tradeoffs... see _the Grantville Gazette, volumes 41-44 for LTA airship design possibilities in the _1632_ universe- and some history of airship propulsion that may be surprising to many)
I think the "radical airship firm Aeros" folks lack some of the ability to think big found in the _Troy Rising_ trilogy by John Ringo.
Why would one want to build things like this for military use? big bucks, limited quantities, more chance of a relatively small (in commercial terms) vulnerability to kill all chances of a payoff.
Go commercial application first- lower bucks per each but once proven, potentially a *lot* more volume of units. *then* harden some for the assault mode...
Airships do not fly by hydrostatic lift: they all need aerodynamic lift too. As they rise the atmosphere gets less dense but the airship doesn't, unless it drops ballast, in which case it has to vent gas to come down again. So airships are filled and ballasted to float just above ground level, and use aerodynamic lift for climbing and cruising.
As far as delivering troops and cargo into a combat zone, I can't see a possible use for this. Too big, too slow and nothing that can't be replicated with fixed/rotary wing aircraft. Perhaps if it was stealthy, maybe for insertion of special operation forces with their equipment to the middle of nowhere where there aren't full-blown hostilities.
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