A spokesman said: "The flight went really well and the only issue was when it landed."
Well, that's kind of every air flight ever. Its sticking the landing that's the hard part. Its not the fall that kills you; its the sudden stop at the end.
There isn't really anything else -- if you look at a periodic table, you can see the next inert gas is Neon, but it is heavier than Nitrogen (which makes up most of the atmosphere).
But it would take an enormous volume of nitrogen to achieve significant positive buoyancy when the nitrogen is enclosed by much of anything. Air's mass is 28.97g/mol, vs. 28g/mol for N2. So, based on my vague recollection of chemistry, that means you only get 1g of container/cargo/engine for every 22.4L of gas enclosed.
> that means you only get 1g of container/cargo/engine for every 22.4L of gas enclosed.
For reference, the Hindenburg carried about 200 million liters of gas. A nitrogen craft would need approximately 1.52 million liters to carry a single 150#/68kg human being, not counting the additional gas needed for the craft itself.
So if you want to build a Hindenburg-size craft to carry about half a dozen people it might actually be plausible!
For the sake of argument, would it be possible to use vacuum? Maybe some kind of spongy structure, with no single points of failure, but lighter than air by way of being mostly nothing?
If your spongy structure is capable of withstanding a half decent vacuum it will likely be much heavier than the volume of that structure filled with air.
No, because there is no known material (even exotic stuff like nanotubes) that can hold a vacuum AND be lighter than the contained volume equivilant of air.
I was wondering the same thing. It would have to be a sphere, a thick shell constructed of an incompressible material such that the inward pressure causes compression. Some kind of honeycomb structure?
The weight of the shell depends on the area (goes up as the square of the radius). The lift depends on the volume (goes up as the cube). Seems like for a large enough size you might be able to get positive lift.
The inward pressure per square inch of shell is constant (14.7 lbs. per sq. in. at sea level with a total vacuum inside), so as long as the inward pressure is distributed evenly it doesn't seem like it has to be stronger just because it is larger.
Inside would only have to be a partial vacuum. You can heat the gas inside to reduce the pressure differential, which might not be too costly if the shell is fairly thick and provides thermal insulation. Here again the volume vs. area works in your favor.
Conclusion: Probably Buckminster Fuller could come up with something.
One of the advantages of large lighter than air craft is that they actually tend to crash in slo-mo, so the "sudden stop" tends to be pretty slow. In the case of the Hindenberg, a lot of the people who died did so because they jumped out too early and fell to their deaths, rather than "ride" the craft down.
Even in the worst disaster, the USS Akron, most deaths were due to drowning and hypothermia after the ship went down, rather than impact.
Well, obviously you don't want to hang around very long after its on (or even close to) the ground. IIRC, most of the burning deaths were crew-members in the upper parts of the ship who were either caught in the fire in its first stages or didn't have a way out even after it hit the ground. The lower decks weren't ignited till it hit the ground.
But the point is that "impact" wasn't a common cause of death for those who stayed in the ship until it was near the ground. Even when the lifting gas is being vented fairly rapidly, they tend to comedown at survivable speeds.
IIRC, most of the survivors simply waited near the bottom until landfall, then walked away. I think many of the victims had a choice between jumping or burning, but it definitely seems like a burning envelope is survivable if (your part of) the cabin doesn't catch.
Maybe the focus should have been on making the cabin nonflammable. Suspending the cabin with an air gap, and lining it (especially on top) with serious fireproof and heat-resistant lining, might have done the job.
It's true the aerostatic lift would help here, but the Airlander 10 is not actually a lighter-than-air aircraft. It's a hybrid and requires aerodynamic lift from forward movement in addition to lift from its engine-driven propellers.
The hybrid approach is puzzling to me because there are a multitude of advantages to be gained by being fully lighter-than-air.
My understanding is that when talking about aircraft, "lighter-than-air" means that it's designed to require no additional lift to keep it aloft regardless of cargo. Anything requiring non-aerostatic lift would be considered a hybrid.
I can think of a couple of advantages of hybrids. You could unload cargo without the thing trying to shoot up in the air and a problem with airships in general is them being blown around by the wind which may be less bad with a smaller hybrids. Also if you emergency land the thing may stay there whereas a fully lighter than air one would tend to drift off.
A minor setback is having to curtail the flight due to a faulty reading on a pressure gauge or a minor power issue with the engine.
A nosedive landing that damages the cabin in perfect flying conditions is about the very worst thing that can happen on an aircraft test programme, even if the flight crew walk away
I'm just saying, a crash that would be a disaster in a regular flight can be "not bad, we learned something here" for a new design on its second test flight.
It was a fun light read. Although at the end I just felt like I got a lesson in really expensive, and partially complete vaporware (vapor-commercial-ware?) and was left with little hope for their future.
Actually, a nose-dive landing occurred at LaGuardia in 2013 - Southwest Airlines - I believe the incident had something to do with the front landing gear failing. There was a small fire (as you mention, jet fuel is quite flammable and if there's a leak and a spark, that's a foregone conclusion, I'd imagine).
But the aircraft itself didn't look too bad which is a testament to decades of engineering experience with a device of such complexity[0].
Jet aircraft rarely nose lands. I'd imagine piloting a 90m helium balloon might be a bit more difficult and therefore result in far more nose landings.
Growing up, we flew in my dad's 4-seat (and later 7-seat) Cherokee very frequently and he'd always comment on his landing. He judged his entire flight by how easy it was to identify when the tire made contact with the runway. I remember a flight in high winds that he put down so softly that nobody could tell when we hit the ground. I also remember a landing when I was alone with my dad where we encountered a cross-wind a few seconds before making contact resulting in my slamming my head into the top of the cockpit and yelling "Mother F*cker!" (I was 14, he'd never heard me swear before and it was a bonding moment that he shrugged it off and thought it was totally warranted given the circumstances).
Bad landings seem to be something that unites almost all pilots. The better ones make bad landings less often, but nobody is immune.
Regarding your bonding moment, one reason I like to fly by myself is so I can swear as much as I want. Part of me is always slightly terrified of having a stuck mic.
Lots of different descriptions around this story:
"Damaged during flight"..."has been damaged after nosediving on landing"..."damage to its cockpit when it hit the ground"..."Collided with the ground"
But only one honest:
"The Air Accidents Investigation Branch has confirmed it is investigating the crash"
It crashed. During flight it collided with a fixed object (technically an "ollision") resulting in damage to the aircraft. On its second a test flight, the experimental aircraft crashed.
Watch the 1080p version.[1] Did they have a control system failure, or was this pilot error? The front fans are steerable, but there's no sign of an attempt to correct the nose-down attitude as the craft dives. Watch the front fan positions. After the crash, the front fans move, but by then the cockpit has been crushed and there's probably nobody in control.
This thing is the same concept as the Skunk Works' P791 prototype - slightly heavier than air, steerable fans - but the flight controls seem to be much less effective and the landing gear is far worse.
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[ 3.5 ms ] story [ 119 ms ] threadWell, that's kind of every air flight ever. Its sticking the landing that's the hard part. Its not the fall that kills you; its the sudden stop at the end.
[1] https://www.hybridairvehicles.com/downloads/download/Airland...
What options exist other than helium?
For reference, the Hindenburg carried about 200 million liters of gas. A nitrogen craft would need approximately 1.52 million liters to carry a single 150#/68kg human being, not counting the additional gas needed for the craft itself.
So if you want to build a Hindenburg-size craft to carry about half a dozen people it might actually be plausible!
The weight of the shell depends on the area (goes up as the square of the radius). The lift depends on the volume (goes up as the cube). Seems like for a large enough size you might be able to get positive lift.
The inward pressure per square inch of shell is constant (14.7 lbs. per sq. in. at sea level with a total vacuum inside), so as long as the inward pressure is distributed evenly it doesn't seem like it has to be stronger just because it is larger.
Inside would only have to be a partial vacuum. You can heat the gas inside to reduce the pressure differential, which might not be too costly if the shell is fairly thick and provides thermal insulation. Here again the volume vs. area works in your favor.
Conclusion: Probably Buckminster Fuller could come up with something.
Neon is insanely expensive however.
But wiki says Ammonia (Hard to combust)-
https://en.wikipedia.org/wiki/Lighter_than_air
Off planet you obviously have other options.
But a complex molecule might work I assume?
Even in the worst disaster, the USS Akron, most deaths were due to drowning and hypothermia after the ship went down, rather than impact.
But the point is that "impact" wasn't a common cause of death for those who stayed in the ship until it was near the ground. Even when the lifting gas is being vented fairly rapidly, they tend to comedown at survivable speeds.
Those were were not trapped either survived or jumped too early.
Maybe the focus should have been on making the cabin nonflammable. Suspending the cabin with an air gap, and lining it (especially on top) with serious fireproof and heat-resistant lining, might have done the job.
The hybrid approach is puzzling to me because there are a multitude of advantages to be gained by being fully lighter-than-air.
https://en.wikipedia.org/wiki/Aerostat
A nosedive landing that damages the cabin in perfect flying conditions is about the very worst thing that can happen on an aircraft test programme, even if the flight crew walk away
It was a fun light read. Although at the end I just felt like I got a lesson in really expensive, and partially complete vaporware (vapor-commercial-ware?) and was left with little hope for their future.
That's a huge win for lighter-than-air flight in my book. A jet aircraft would be a smear of aluminum, carbon fiber, and jet fuel all over the runway.
But the aircraft itself didn't look too bad which is a testament to decades of engineering experience with a device of such complexity[0].
[0] And found a link! http://gothamist.com/2013/07/23/video_southwest_planes_nosed...
Growing up, we flew in my dad's 4-seat (and later 7-seat) Cherokee very frequently and he'd always comment on his landing. He judged his entire flight by how easy it was to identify when the tire made contact with the runway. I remember a flight in high winds that he put down so softly that nobody could tell when we hit the ground. I also remember a landing when I was alone with my dad where we encountered a cross-wind a few seconds before making contact resulting in my slamming my head into the top of the cockpit and yelling "Mother F*cker!" (I was 14, he'd never heard me swear before and it was a bonding moment that he shrugged it off and thought it was totally warranted given the circumstances).
Regarding your bonding moment, one reason I like to fly by myself is so I can swear as much as I want. Part of me is always slightly terrified of having a stuck mic.
[0]https://en.wikipedia.org/wiki/Empire_of_the_Clouds
But only one honest: "The Air Accidents Investigation Branch has confirmed it is investigating the crash"
It crashed. During flight it collided with a fixed object (technically an "ollision") resulting in damage to the aircraft. On its second a test flight, the experimental aircraft crashed.
This thing is the same concept as the Skunk Works' P791 prototype - slightly heavier than air, steerable fans - but the flight controls seem to be much less effective and the landing gear is far worse.
[1] https://www.youtube.com/watch?v=DkYbw4R_-RQ