Comment by AlexMuir | Hacker News Reader

Comment by AlexMuir | Hacker News Reader

The insurmountable problem so far on these cargo airships is ballast. It's what killed off the Cargolifter Project (as I read while sitting naked under a palm tree in its former hangar. [0])

Their killer use case is moving heavy stuff to inaccessible areas. Wind turbines being the flavour of the moment. They combine the long distance capability of a plane, the hovering of a helicopter and the lift capacity of a crane...

However, once the 160 tonne payload has been dropped, the ship either needs to take on 160 tonnes of ballast or jettison helium (not an option since it's so expensive). The Cargolifter idea was to just pump up water if I remember correctly, but for land-based tasks that meant being met by ten tanker lorries at the drop site, thus negating all the benefits and meaning you might as well stick the cargo straight on those trucks.

I'd love to see it work out, but so far these projects have been nothing but a wipeout for investors. Coincidentally back in 2006 I worked a couple of desks over from people managing the liquidation of Skycat, which was basically the same thing, also built at Cardington. It may even have been the same team.

[0] http://en.wikipedia.org/wiki/Tropical_Islands_Resort

Compress the helium into tanks and use atmosphere as ballast. Ballast can be dropped by directly purging with helium. Alternatively, contain the ballast in bladders that vent as helium pressure rises. Designing flexible bladders that don't leak too badly would be an engineering problem. A terribly inefficient option would be to allow the gasses to mix and just use fractionation to separate the heavy elements when dropping ballast.

It exists. http://rt.com/news/aeroscraft-revolutionary-airship-cargo-18... (Feb 2013)

It seems like it should also be usable for shipping between non-remote places, in situations where you need more speed than a boat can provide but don't want to pay the full premium for air freight.

For instance, I seem to recall that Apple ships their laptops by air from Asia to keep the supply lines short. Shipping by boat might be too slow, but this thing might be able to cross the Pacific quickly enough, and at a lower cost than a conventional airplane. A route like this would have warehouses on either end, so you could easily have ballast waiting for the airship whenever it needed it. (You'd probably just pump water from the Pacific at one end, then put it back in the Pacific at the other end.)

>(You'd probably just pump water from the Pacific at one end, then put it back in the Pacific at the other end.)

You most certainly would not. Because the risk of spreading invasive marine species the MARPOL convention doesn't allow it. This means ships have to gradually replace all their ballast water during a passage. Just don't repeat Cougar Ace's mistake: https://en.wikipedia.org/wiki/Cougar_Ace

An interesting, though probably semi-insane, alternative.

What about having a tank on-board, that normally is filled with air, that, when you drop off the payload, gets filled with liquid air instead? It'd be power-hungry, but meh. I mean: liquid air has a density of ~0.87g/cm^3 - it's not so far off that of water.

Tank mass would kill you, but as you say, the actual lifting capacity is relatively cheap.

Many years ago (in the 80s), my parents took me on a road trip which happened to go through Tillamook, OR (yes, famous for cheese). At the time there were two huge WW2-era blimp hangars there, one of which housed a company building a blimp that had a rather novel solution to this problem. The blimp itself was neutrally buoyant and had four wing-like rotors with propellers at the end; the whole unit spun slowly. Lift and angle/direction were controlled by changing the blade angles like a helicopter. They were out field testing it, which is why we stopped by and chatted for a couple hours (yes, I am the son of engineers).

Picture a cross between a blimp and a Triebflügeljäger.

I heard they went out of business before getting it into production and I can't seem to find any relevant information on Google. Anyone know what it was called? I imagine that it would be much easier to develop the control systems today than it was back in the early 80s.

Since then, one of the two hangars burned down and the other has been converted to an air museum. The structure itself is actually worth a visit on its own - one of the largest wooden structures in the world.

Exactly this, and you can't really navigate in cross winds (although the M&M shaped craft was trying to negate that by being a saucer). The steam punk in me would love to see zeppelins again in the sky but I somehow doubt we will.

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