Hydrogen-Powered Aircraft == Anti-Terrorist Device?

maladroit asks: "Today on NPR's Talk of the Nation/Science Friday , Harry Braun of the Phoenix Project said that a hydrogen-powered airplane would not have produced the fire and intense heat that brought down the World Trade Center towers. Is this true ? What are the other advantages and disadvantages of hydrogen fuel ? Details on the Phoenix Project's website are a bit sketchy, but I'm sure the Slashdot crowd has some answers (and Richard Dean Anderson jokes)." Sounds like a good theory, it doesn't account for the hostage aspect, but it would prevent the use of aircraft as cheap bombs. Would there be any drawbacks? How much would such a refit cost for your average commercial aircraft?

Comments

Remember the Hindenburg?

[jvv62]

I think you still have problems with a big explosion. What you probably won't get is a long burning hot fire. The explosive tendency of hydrogen gas is one of the reasons that you haven't seen those super clean burning fuel cells in standard passenger cars yet.

Re:Remember the Hindenburg?

[sh00z]

Why did you post this anonymously? Some of us browse at +1 to avoid the crap, but this is the single most informative piece of information to give the folks who still believe that it was a hydrogen fire (well, maybe you could have posted this link).

And moderators, please mod me as redundant AFTER you mod the parent up to informative. The Anonymous Coward wrote:

The Hindenburg's demise was not a result of an initial hydrogen-fueled explosion.

It caught fire because of the way the airship was designed, and how it dissipated the electrostatic charge that built up on the outer skin.

The ship's skin was a series of panels that were stitched (not really, more like tied) together. When the landing lines are lowered, the charge in these panels are supposed to flow through the entire skin of the airship and down the landing lines.
Because of poor design/construction, some of these panels retained their electric charge because of poor contact with their surrounding panels. The voltage between the charged panels and the non-charged panels was great enough to produce a spark.

BUT... the spark did NOT ignite the hydrogen.
The spark ignited the SKIN.
Since the skin had to be reflective to reflect heat, the germans coated the skin with a mixture that contained aluminum oxide powder.

Sound familiar? Aluminum oxide powder is used as solid rocket booster propellant in the space shuttle.

It was the fire on the skin that ignited the hydrogen cells. Hydrogen burns clear, and is barely visible in daylight. The initial fire on the airship was orange-red.

Re:Hydrogen burns

[Seanasy]

It wasn't hydrogen burning.
From the DOE H2 website:

Did hydrogen cause the Hindenberg to blow up?

No. A recent study of the accident implicates the paint used on the skin of the airship, which contained the same component as rocket fuel.

Re:Hindenburg

[chporter]

The reason the WTC collapsed was not because the crash weakened the structure. The planes were full of jet fuel for the trips across the country. (This is said to be part of the terrorist plan.) The high-temperature of the burning jet fuel compromised the structural integrity of the steel, which is why the building collapsed. If the jets were relatively empty, like they would be on a trip from Boston to NY the fires would not have lasted as long and the building would probably still be standing. The WTC towers were designed to withstand impacts from large aircraft (707? 727?) and the steel was designed to withstand heat for prolonged periods of time.

The hydrogen fuel would not burn as hot and also would evaporate very quickly.

Re:Hindenburg

[Hieronymous Coward]

You are right. The burning fuel brought down the towers, and it took an hour. The impact of the plane was negligible to the structure - it would have destroyed a floor or two worth of office equipment/drywall, but the building would be back in use within days.

Kinetic energy didn't take down the towers.

[DunbarTheInept]

The impact of the planes did not destroy the towers. They were build to take a *massive* shakedown like that and still stand. They fell because the steel they were made out of started getting mushy when their temperature approached the melting point of steel. In other words, take out the fuel fire and just have the kinetic energy of the impact and the towers would have stood. (but the damage would have been bad enough that it would still have taken a long time to fix them.)