Boeing-Skyhook Airship Faces Technical Challenges

waderoush writes "Since the Hindenburg disaster, dreams of giant airships capable of lifting heavy cargo have been restricted mainly to Popular Science covers (with the notable exception of the Cargolifter AG failure) — until Boeing and a Canadian company called Skyhook announced on July 8 that they're building a 300-foot-long, helium-filled craft that will lift loads of up to 40 tons and carry them 200 miles. But an aeronautical engineer at the University of Washington cautions that there are still some big problems to be worked out with mega-airships, including their stability in turbulent weather."

Comments

Oblig. Simpsons

[name*censored*]

Wow, it seems we're coming full circle with air travel..

"I'd like to send this letter to the Prussian consulate in Siam by aeromail. Am I too late for the 4:30 autogiro?"

Re:Oblig. Simpsons

[DaedalusHKX]

Ironically, when the Hindenburg (which was among a tiny minority of airships that actually crashed) wrecked, a scant few people were killed, a couple injured, and the rest survived. When an airliner crashes... well, survival chances are... not quite as good. So lets get it right, if an airliner pilot wrecks the plane, you're fairly likely to DIE. If a zeppelin or something to that effect crashes, you've got a fairly good chance to tell a "wow look at me" story about your "shipwreck adventure" which is probably why the Hindenburg got such note...

Do your own research on the subject, but they actually were safer than airplanes (and significantly more economic). Either way, hopefully you'll dig up your own research on the subject.

Re:Oblig. Simpsons

[b0s0z0ku]

Ironically, when the Hindenburg (which was among a tiny minority of airships that actually crashed) wrecked, a scant few people were killed, a couple injured, and the rest survived. When an airliner crashes... well, survival chances are... not quite as good.

This was a crash upon landing -- i.e. the airship caught fire at an altitude of about 100 ft when approaching its docking tower. Your chances of surviving an airliner wreck from 35,000 feet are quite small -- your chances of surviving a crash or fire upon a (somewhat controlled) landing are much greater.

-b.

Re:Oblig. Simpsons

[GleeBot]

Actually, chances of surviving a fire on the ground in an aircraft are quite low. Most of the fatalities in air crashes come from people who burn to death shortly after impact, rather than the impact itself.

I'm also reminded of numerous crashes which happen quite close to the ground which result in massive casualties--Tenerife, in particular, comes to mind. The greatest loss of life in aviation history came about because of a collision on the ground.

One of the things that makes airline accidents so deadly isn't necessarily the altitude, but the speed and the fact that these things are carrying so much damn fuel. I wonder which has more energy, the envelope of the Hindenburg or your average passenger jet fuel tank...

(Incidentally, airships can crash land from quite high altitudes with minimal ill effects. Because they're lighter than air, and contain so much lifting gas, even sizable holes leak quite slowly in comparison to the envelope volume, and the airship drops slowly. Fatal airship crashes have usually involved loss of control, rather than a sudden loss of lift; even the Hindenburg, with the entire envelope aflame, crashed rather gently.)

Re:Oblig. Simpsons

[Original Replica]

Not if you factor in that time = money. Then they aren't so economically competitive with jet aircraft because of how slow they are.

For business trips, I agree with your point. For vacation travel I might disagree, depending on the cost and luxury of airship travel. A airship ticket from NYC to London that costs the same as the airplane ticket might be a good deal if I have a decent sized seat and can walk to a dining area and eat real food on my 24 hr trip as opposed to being cramped in an economy seat with a microwave meal for 7 hrs. If the trip is actually part of the vacation it could be worth it.

Re:Oblig. Simpsons

[drinkypoo]

I'm also reminded of numerous crashes which happen quite close to the ground

Most crashes happen quite close to the ground, with the exception of midair crashes, which are comparatively rare.

Re:Oblig. Simpsons

[cyclone96]

One of the things that makes airline accidents so deadly isn't necessarily the altitude, but the speed and the fact that these things are carrying so much damn fuel. I wonder which has more energy, the envelope of the Hindenburg or your average passenger jet fuel tank...

Interesting question. I did some quick googling and math. I wasn't particularly careful, so corrections are welcome.

The Hindenburg had a gas volume of 200,000 m^3, at 0.089 kg/m^3 standard density of hydrogen gas, that is a total hydrogen load of 17,800 kg. Hydrogen has a high energy density of 143 MJ/kg.

A fairly heavily loaded 747 will be carrying 136,000 kg of Jet-A at 43 MJ/kg.

So, the 747 has more than twice the energy onboard, although smaller jets would be rougly equal, all depending on the fuel load. I also did not include the diesel onboard the Hindenburg (or its rather flammable aluminum paint).

One significant difference between hydrogen and Jet-A burning is that the hydrogen is going to rise once the gas bags rupture and not hang around on the ground like Jet-A.

Again, I read the article

[holophrastic]

This is, once again, a stupid and worthless article. Allow me to summarize again.
1. Someone's trying to build something
2. Someone else says it was hard a few decades ago

That's it. Gee, thanks for the news. Once again, "Someone is going to try to do something" is not a headline!

Where's the beef?

[BrotherBeal]

There's got to be more to this analysis than TFA leads on. I mean, identifying turbulence as a problem is hardly a feat of aeronautical engineering. We've been flying aircraft of many varieties for a long time, and it's not as if we don't have strategies in place to deal with turbulence or any of the other weather conditions that exist (which TFA seems to confuse with turbulence). Problems with aerodynamic control are hardly showstoppers either. If worse comes to worse, put a tail-rotor on the thing just like a helicopter, or use counter-rotating props. As for the third problem (the high price of helium) - that's hardly a "technical challenge". If companies feel this new design opens some profitable avenues, they'll find a way to fund it - otherwise, it will remain a prototype. I'd like to hear what this engineer ACTUALLY had to say, since the folks at xconomy.com seem to have left nearly all the meat out of his critique.

Re:Where's the beef?

[Deadstick]

and it's not as if we don't have strategies in place to deal with turbulence

We certainly do. The one for aerostatically-suspended vehicles is "Fly in nice weather".

An airplane suspends itself entirely with aerodynamic force, which the pilot can manipulate to a high degree and on a very short time scale. Hit a downward bump, pull back a little on the stick, lift increases, flight path remains nearly constant.

An airship suspends itself principally with an aerostatic force which can't be modified very much, and maintains the desired flight path with relatively small aerodynamic forces which are manipulated in the same way as an airplane. The latter forces just don't have enough range to deal with serious turbulence.

Besides making maneuvering difficult or impossible, turbulence presents another threat: stress. While the aerodynamic forces the pilot can apply are small, the ones a thunderstorm can apply are not. Aerodynamic forces depend on the surface area of an object, and the surface area of an airship is huge. Big forces, big stresses on a necessarily lightweight structure.

rj

I can fix that one ...

[ScrewMaster]

But an aeronautical engineer at the University of Washington cautions that there are still some big problems to be worked out with mega-airships, including their stability in turbulent weather.

Well, duh. Don't fly them in a storm them. Geez, do these guys need to have everything explained to them?

Re:Helium Crisis Approaching

[b0s0z0ku]

It could use hydrogen gasbags within an envelope filled with pure nitrogen to prevent mixing with air and combustion. Technology has come a long way since the Hindenburg, and hydrogen airships could be made safe. (BTW, some theories state that the Hindenburg accident wasn't caused directly by the hydrogen gas but by the fact that the ship was painted with a flammable aluminium-based paint).

-b.

Re:IF it works

[BlueMikey]

Unless we run out of helium.

http://www.wired.com/wired/archive/8.08/helium.html

"At our current rate of consumption, Cliffside will likely be empty in 10 to 25 years, and the Earth will be virtually helium-free by the end of the 21st century."

Re:Oh, its a headline alright, to many people.

[holophrastic]

You mis-understand me. "people are trying to build an airship" is news-worthy even if they were built every day. But that's not this article's focus. This article focuses on how some other people (not the airship builders) mention problems with airship design. This article is about raining on someone else's parade.

What makes it particularly stupid is that these people who are predicting the builders' failure are doing so in an industry where virtually nothing has been done for decades. So essentially they are using antiquated data to argue against current endeavours. That's not only mean, it's retarded -- in the correct sense of the word.

Re:IF it works

[Oktober Sunset]

pffftt. Helium is for wimps. Have some balls and use hydrogen.

Mods on crack?

[spectrokid]

Let me summarize responses which for some weird reason have been modded down:
+ 200 miles in a blimp = 8 hours You fly around with a refinery cracking tower for 8 hours you gonna want to take a leak.
+ Any long distance you do by ship or train. Pick up your oversized baggage directly from the ship, and fly it to its final destination.
+ If I can add my own: the weather can change a lot in 8 hours. Flying into a storm with a 50 ton windmill hanging from your butt is bad news.