Global Observer's First Hydrogen-Powered Flight 34
cylonlover writes "Following on from a successful maiden flight under battery power in 2010, AeroVironment's high altitude, long endurance (HALE) Global Observer unmanned aircraft has now taken to the skies using hydrogen-fueled propulsion. The aircraft reached an altitude of 5,000 feet during the four hour flight on January 11 at Edwards Air Force Base (EAFB) in California. Both the endurance and the altitude of the system will be expanded in further test flights in order to achieve the planned operational altitude of 55,000 to 65,000 feet."
seemed like we had many hydrogen fueled... (Score:2)
aircraft in the 1930's.... ...also seems like it didn't end well for some of them.
Re:seemed like we had many hydrogen fueled... (Score:4, Informative)
aircraft in the 1930's.... ...also seems like it didn't end well for some of them.
I hate to put on the Internet Professor hat, but.. Hindenberg wasn't propelled by hydrogen, it was used for it's lighter than air qualities and was propelled by diesel engines.
The problems it had were probably a combination of multiple elements of its construction, not just the hydrogen. Kinda different situations.
I get that you're trying to make a joke but.. funny things are based in truth, hilarious things are true.
Re: (Score:2)
> I get that you're trying to make a joke but.. funny things are based in truth, hilarious things are true.
Now, are you just funny or are you hilarious?
Re: (Score:2)
Re: (Score:2)
As others stated, they were not powered by hydrogen. And airship, such as the Hindenburg, had a very poor combination of elements which all but demanded disaster. For starters, because hydrogen is so small, requires a special coating to prevent it from escaping its rather large, cotton, bladders. Their solution? Coat the cotton airship with thermite [wikipedia.org].
You can read more about it here [wikipedia.org]. Even Myth Busters did a segment on it which more or less confirms the thermite theory mentioned in Wikipedia's Hindenburg artic
Seems like a very bad idea! (Score:1)
Polluting (Score:1)
Re:Polluting (Score:4, Informative)
Re: (Score:2)
Water vapor comes and goes.
CO2 stays a long, long time.
Re: (Score:2)
Why hydrogen? (Score:2)
Re: (Score:3)
Re: (Score:2)
Liquid hydrogen has a very high energy density
"Very high energy density" is a very broad observation- a proton has a very high energy density compared to vacuum, so what? How does it apply to this particular engineering challenge?
That's also why it's a great rocket fuel.
It's a particularly crappy fuel, highly volatile and inefficient, and cumbersome in the sense that the Oxygen used for combustion has to be carried along. One wrong move, and the whole thing turns into a very expensive and deadly firework. But for very large payloads, it's the only one there is.
I think you are missing the poin
Re: (Score:3)
> "Very high energy density" ... How does it apply to this
Interesting strategy. Not exactly circular, perhaps a spiral:
1) Lobby for a diesel-burning plane, asserting diesel has a higher energy density than Hydrogen
2) Get corrected by first guy that comes along
3) Claim energy density has nothing to do with "this particular challenge"
4) Claim the plane shouldn't burn fuel
5) Complain things 'whooosh' by.
AeroVironment makes craft that fly pretty well. Been doing it as long as I can remember. And the compa
Re:Why hydrogen? (Score:4, Informative)
Woops. I somehow thought khallow's post and arisvega's post were from the same person.
Sorry guys.
Arisvega - energy density is important for aircraft because it needs to weigh as little as possible. Batteries have about the worst energy/weight ratios you can find.
Khallow - AeroVironment doing diesel is about as likely as the NRA lobbying to ban guns.
Re: (Score:2)
Liquid hydrogen has a very high energy density
Things like diesel fuel or methane have higher energy densities. The relatively low energy density of hydrogen is actually a problem in rocketry, it leads to oversized tanks which can hurt the overall mass fraction of the vehicle.
Re: (Score:2)
That is energy density compared to volume, it does poorly there. Mass wise it does quite well.
Re: (Score:2)
I think NASA has something to say about hydrogen powered flight.
I had the Shuttle and the Delta IV in mind when I made my observation.
Re: (Score:2)
Re: (Score:2)
Because hydrogen as a fuel does not inherently pollute nor is it inherently carbon positive. It has a lower potential energy than most forms of petroleum so the fact that they were able to make a plane that flies 4 hours on a tank of fuel is important.
The only problem with that statement is there is no such thing as "hydrogen fuel".
Hydrogen is non-polluting only if you ignore all the processing that goes into producing the hydrogen. It's like using a 2-stroke gasoline generator to charge up your electric car, and then declaring it a non-polluting vehicle. The hydrogen has to come from somewhere...and it's not just buried in the ground like petroleum, it has to be produced...and that process is at a net energy loss.
People who are overly excited abo
Re:Why hydrogen? (Score:4, Informative)
Because hydrogen as a fuel does not inherently pollute nor is it inherently carbon positive. It has a lower potential energy than most forms of petroleum so the fact that they were able to make a plane that flies 4 hours on a tank of fuel is important.
The only problem with that statement is there is no such thing as "hydrogen fuel".
I said "hydrogen as a fuel" and not "hydrogen fuel" to avoid silly hecklers like you, but it really doesn't matter because "hydrogen fuel" is an accurate statement anyway. Here's the definition of "fuel" since you seem to be confused: Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner.
Hydrogen is non-polluting only if you ignore all the processing that goes into producing the hydrogen. It's like using a 2-stroke gasoline generator to charge up your electric car, and then declaring it a non-polluting vehicle. The hydrogen has to come from somewhere...and it's not just buried in the ground like petroleum, it has to be produced...and that process is at a net energy loss.
Which is why I used the word "inherently" specifically twice. As you noted later, how much pollution is introduced depends entirely on the method used to create the electricity needed for electrolysis. There's no reason it has to be from a polluting source. A hydroelectric dam, wind farm, solar station, or thermoelectric plant could produce it during off peak hours. There are problems with hydrogen, mostly having to do with the high pressure to store it, but you seem to lack understanding in what the actual limitations are and instead forming circular arguments.
People who are overly excited about the "hydrogen economy" are woefully underinformed on things like the laws of thermodynamics. Hydrogen is never going to be a efficiency gain, it can't be. It can be a practical energy STORAGE medium, but it's going to require a cheap/nearly unlimited energy source to start with...like nuclear power. But of course, once you have cheap plentiful electricity, the hydrogen doesn't make much sense.
You've become absurd in your rant. You correctly call it a storage medium (that's all fuels are really) and then go on to say if we had cheap and "clean" nuclear power we wouldn't need a storage medium anymore. Do you expect planes and cars to have small nuclear power plants in them? This is exactly why hydrogen as a fuel is important. You don't have to go mining for dangerous heavy metals to put in batteries or pollute with fossil fuels to get the required energy density.
And of course it's not "efficient", we don't have a good "efficient" way for producing durable (as in the economic sense) energy yet. That's why this is important research. We can dig fossil fuels out of the ground, but it's not like we can actually produce fossil fuels for an "efficiency gain".
Re: (Score:1)
Re: (Score:2)
Because hydrogen as a fuel does not inherently pollute nor is it inherently carbon positive.
That's not useful to a military. And as the other replier noted, it doesn't inherently pollute less than a hydrocarbon fueled vehicle.
It has a lower potential energy than most forms of petroleum so the fact that they were able to make a plane that flies 4 hours on a tank of fuel is important.
Do you mean that hydrogen fuel has a high energy per mass ratio?
First Hyrogen Fight? (Score:1)
Tupolev Tu-155 flew using hydrogen for propulsion (Score:1)
From Wikipedia article:
"The Tu-155 first flew on 15 April 1988. It used hydrogen as fuel, and, later liquified natural gas (LNG). It flew until the fall of the Soviet Union and it is currently stored in the Ramenskoye Airport near Zhukovskiy."
And then they discovered cheap oil...