The whole proposition of hybrids is that they don't need tethers because they are heavier than air.

That will be until the wind blows over the aerofoil envelope and creates 20T of lift! :p

That indeed may be. I believe the suction hover-skirt is aimed at dealing with that. Not that I know how capable it is.

20T of suction is going to use a lot of power and, unless there is a perfect seal, will need to be generated for a long period. The more I hear about this, the more I think it is madness...

LJ

(In a Scottish accent) It will end in tears!

Time and again the proposers of these systems forget about how easy and vulnerable they are to hostile action. Military systems are targets in times of conflict and expecting the enemy to take pity on one of these lumbering hybrids is not a realistic hope.

Yes, because if you put up a big balloon in Afghanistan it would immediately be shot down......

Oh, wait...

Ahh a proponent of the 'next war will be just like the last one' theory.

Enjoy your job at the Treasury.

Actually, the opposite is true. Both the US and UK militaries have fired rounds of varying calibres - up to and including 20 mm - into HAV-made vehicles and have even tested the effect that a SAM might have, in a bid to determine their vulnerability. In each instance, the airships survived, in most cases so well that, faced with similar ammunition in combat, the crew probably would not notice that they had been the subject of an attack.

There are several reasons for this, chief among them the fact that helium is an inert gas and so incapable of igniting even when exposed to a tracer round or missile detonation. While the hull's fabric was pierced by both the entry and exit passage of the round, the gas inside was contained under such a low pressure (1/10th of 1 lb per square inch) - and there was so much of it - that although the hull was riddled with holes it took hours to deflate significantly.

It was concluded that a SAM would pass straight through without detonating, leaving two relatively small holes. Tests established that it would take the vehicle three and a half hours to deflate with these two holes in the skin.

A warhead was also strapped to the inside of a fully inflated test hull and detonated to test the airship's behaviour if a SAM were to explode inside the envelope. The results of the experiment were somewhat surprising, blowing out the windscreens out of the testers' cars, but having the hull just going 'boing' and coming back out again. And although the casing from the explosive made a number of shrapnel holes, they were irrelevant.

Even if such holes were numerous, they would have little effect on the vehicle as the helium would not be escaping under pressure. As a result, the damaged fabric skin has a natural tendency to seal itself. Also, as there is no internal structure to the envelope (it is fully supported by the pressure of the gas), there are no parts to damage.

I led one of the UK/US vulnerability studies which tore apart the company manufactured theories. You can only imagine how keen they were to show how inert helium was whilst ignoring vulnerable systems and the pink fleshy things inside.

About the only positive I could state is that if an enemy was dumb enough to repeatedly target the big empty space then they may have a chance. Should the enemy choose to target the other things then it would get messy.

To tease the company we even showed how simple it would be to ruin their much vaunted helium envelope, just for fun. A helicopter laying an explosive rope along the top would do the trick. At one stage people were looking into how to defend against the threat of being boarded inflight. Anyway, a burst of fire or a missile or 2 into the flightdeck is much more traditional. If you target the engines and consult the metman you may even find a load of nice equipment downwind somewhere.

Still, these things are so slow that there is plenty time for the enemy to learn on the job.

:ok:

While you could armour the gondola, you would of course be trading payload for weight. Of course, there's always the unmanned option as envisioned for LEMV.

Already in the 'real-world' HAV and others fly these airships across the States and North America on a regular basis, where they are repeatedly shot-up by every hick with a firearm. Ive been told anecdotely that they often arrive at their destination peppered with bullet holes, and to date none have been lost to such ground fire.

Of course, a large part of surviveability is being smart as to where and when you use it. There are planty of platforms in service today that you'd think twice before deploying directly into harms way, and yet they all have a role to play.

The armour vs weight issue taxes all the slow movers. HAVs do have a significant weight lifting advantage but it is difficult to see how they could armour it enough given the lack of ability to run, hide or manoeuvre. The company did honestly look one of our team (an Apache pilot) in the eye and said when they add armour his little bullets would just bounce off.

'You do know we are reasonably good at plinking main battle tanks don't you?'

I don't think anyone is talking about flying these things into any environment worse than the risk of small arms (disperse your redundant systems and a bit of Dyneema around the soft pink bits) and MANPADS (IR aimpoint goes where?).

As for wind: I have not seen an HAV with a pressure cabin so we are talking low altitudes, where mean zonal winds can be around 30 mph max - not impossible with an 80 knot/90 mph cruise. Now use satellite weather planning to route around the worst of it.

http://showcase.netins.net/web/wallio/MZW_12mo.gif

I think there is a case for a tech demonstrator to prove out long-range cruise, operability and ground handling. Aeroscraft has done quite a lot on limited money, and HAV Ltd is working on the ex-LEMV. This actually is something that is being taken seriously in a lot of places despite the fact that there is not a lot of government money to be had, and that's a good sign.

Besides, you'll never see a heavier-than-air craft that, for some unaccountable reason, reminds you of Kim Kardashian.

http://airpigz.com/storage/2012-augu...=1344710075000

I am reminded of the song that starts


"All of a sudden a ruddy great b@ll@ock came flying through the air............"

Looks like a flying arse - oh, it is...:ok:

It is a very disappointing fact that most people seem to assume that just because something has never worked before that it never will.
Fortunately the human race has those who are not so easily put off.

Especially if they can get someone else to pay!

I remember Aerospace Developments and then Airship Industries making grossly exaggerated claims as to their abilities back in the 70s, ISTR it was ASW/ASUW then. No matter how many times they were told to go away they kept turning up like the proverbial bad penny.

If HAV only works in 'ideal' conditions and scenarios, what is the point of depleting ones limited financial resources on such a beast only to end up with fewer more capable platforms?

Was Harold Camping involved with this project too?

If airships or hybrids had failed after receiving one-tenth of one percent of the R&D investment lavished on tilt-rotors or STOVL one might be justified in writing them off. As it is, the technology has suffered from all the ills that could afflict it: bounced around from one service sponsor to another, drip-fed money in tiny increments one minute and expected to yield 500 ton payload monsters the next.

LowObservable wrote: Nevertheless, these totally useless windbags are simply a complete and utter waste of time, money and effort. If the snake-oil salesmen, who are trying to sell these ridiculous pieces of junk to the military, had any real belief in their project, they'd already have identified a niche market. But it's clear that they're trying to find a solution to a problem which, frankly, doesn't actually exist.

And Bruce, stick to Heavy Metal.....