World's Largest Aircraft Completes Its First Flight (cnn.com)

The world's largest aircraft has finally completed its first flight after months of preparation and years of searching for funding. The Airlander 10 as it's called spent 20 minutes in the air on Wednesday, landing safely at Cardington Airfield north of London. CNNMoney reports: "Part airship, part helicopter, part plane, the 300-foot long aircraft is about 50 feet longer than the world's biggest passenger planes. The Airlander, made by British company Hybrid Air Vehicles, has four engines and no internal structure. It maintains its shape thanks to the pressure of the 38,000 cubic meters of helium inside its hull, which is made from ultralight carbon fiber. The aircraft was originally designed for U.S. military surveillance. But the project was grounded in 2013 because of defense spending cuts. [The team behind the giant blimp-like aircraft] said the aircraft could carry communications equipment or other cargo, undertake search and rescue operations, or do military and commercial survey work. The Airlander can stay airborne for up to five days at a time if manned, and for more than two weeks if unmanned. It can carry up to 10 tons of cargo at a maximum speed of 91 miles per hour. The aircraft doesn't need a runway to take off, meaning it can operate from land, snow, ice, desert and even open water." You can view the historic flight for yourself here (Warning: headphone users beware of loud sound).

Comments

Re:Waste of helium

[Anonymous Coward]

So this is a waste, but party balloons ore ok? Because I guarantee a lot more He is wasted on party balloons than will ever be used on these aircraft, by many orders of magnitude.

Re:Waste of helium

[Rei]

Helium is a rare element on Earth, despite being common in space. We need to be conserving our helium supplies. Why are we wasting helium on stuff like this?

Sigh, this stuff again....

1) All lifting uses combined (party balloons, blimps, etc) make up a fraction of the 13% "other" category.. The big wasters are industry, where they buy either gaseous (e.g. welding) or liquid (e.g. cryogenics) and just dump it to the outside air. No recovery effort whatsoever. To the people who run cryogenic / industrial equipment: Yes, I know, recovery systems are a cost and it's always iffy whether it pays for itself. But you, "cryogenic people", and you, "we're running out of helium people", fight amongst yourselves and leave lifting purposes - which use little helium - out of it.

2) Of that fraction of a 13% dedicated to lifting purposes, blimps use only a small fraction of it.

3) Modern fabric for blimps such as vectran or aluminized BoPET leak literally several orders of magnitude less than old fabrics like polyurethane-coated nylon.

4) Old style blimps need regular venting to adjust lift. Part of the purpose of this new generation of hybrid blimps is that they don't have to do that. And it's not the only type that can do this; variable-superpressure blimps can as well, as can phase-change blimps (see project ALICE).

In short, you're looking at a tiny fraction of a tiny fraction of a small fraction of a fraction of 13% of helium usage. No, this is not a problem. Furthermore, concerning helium itself:

1) It's not clear that we're anywhere near "running out of helium". Helium hasn't been studied nearly as much as more economically important resources like oil and gas. We really don't even understand why most deposits that are rich in helium are like that. Entire new categories of helium deposits, such as volcanic helium, are looking increasingly likely to be economical (it had previously been thought uneconomical because it would all be diluted with CO2; we're now finding that this isn't always the case). We're finding out that groundwater plays a role in where helium migrates to. And on and on. As helium prices rise, more work is finally getting put until understanding helium resources and finding new ones. It used to be just way too cheap for that.

2) The absolute worst case for helium is refrigerating it from the atmosphere, as the end stage of what we currently do to separate other noble gases. By volume, neon is about 3,5 times more common than helium, while helium is about 60 times more abundant than xenon; so the volumetric price for helium should be between that of neon and xenon, but closer to neon. Expensive, but still available. Except for one thing...

3) ... we'll never get to that point. Because any gases from the ground will always be significantly more helium rich than the atmosphere, so we'll always use them as our source. Even if today's helium resources do get depleted (not likely anytime soon, see #1), it just means a steady progression to less helium rich gases (including virtually limitless volcanic ones) as the source. It will never approach the price of gases like neon, even in the worst case.

Also, from the summary:

The Airlander, made by British company Hybrid Air Vehicles, has four engines and no internal structure. It maintains its shape thanks to the pressure of the 38,000 cubic meters of helium inside its hull,

Um, no, it's not. Blimps don't work that way. Loads are distributed at the very least by catenary curtains and cables.

If you want a small scale example, take a garbage bag, blow air into it, and tie it off (blimps only have a couple hundred pascals overpressure, they're not like party ballons). Now hang a weight from it. Notice how horribly it deforms. You need catenary curtains to distribute the weight of your load across the fabric, to maintain your desired (aerodynamic) shape. You also need ballonets, so that the blimp doesn't explode when you change altitude.

Re:Waste of helium

[Rei]

An envelope filled with N2 around each hydrogen cell would make a Hindenburg-style explosion pretty much impossible.

It doesn't work that way. Ignoring the tremendous amount of extra mass you're proposing and the increased cross section, hydrogen does not instantly dilute; by and large it will just rise through the nitrogen to the outside. Furthermore, hydrogen has an incredibly broad flammability range; you only need a couple percent H2 for it to burn.

Also, because the H2 molecule, being composed of two atoms, is twice as large as the He atom (helium doesn't pair with itself to form molecules), which only has one atom, it will take MUCH longer for the hydrogen to escape through the pores of the gas bag/lifting cell.

Permeability does not work that way. Permeability is a complex process involving not just porosity but also affinities and solubilities. As a general rule, hydrogen and helium permeabilities are quite similar.

a volume of hydrogen molecules is still halt the weight of the same volume of helium atoms.

It's actually not that much of a difference because both are vastly lighter than air (2 vs 4 vs. 29).

LZ-126/U.S.S. Los Angeles gives a real world example of the difference between operating the same ship with helium versus hydrogen.

It's not that simple. They didn't just switch lifting gases, they also added an exhaust water recovery system (aka added weight and a bit of extra drag and a bit of parasitic energy consumption). Range of an airship is relative to its drag, its energy efficiency and the amount of fuel it can carry.

if the Hindenburg had used helium instead of hydrogen,. it would have never got ff the ground.

They wanted to use helium as the lifting gas, and lobbied the US for permission to import it. They actually designed the airship around the premise that they'd be able to convince the US, and had to redesign it when the US refused. Zeppelin, the world's biggest producer of hydrogen airships, still preferred helium. Hydrogen was out of necessity, not desirability.