My comment has been eaten.
I was saying this is a really practical range, and I did not expect something like this to happen so soon.

I applaud the R&D effort, but am very skeptical about the range claims.

> A liquid hydrogen tank is low weight.

Actually, no. Hydrogen storage systems are very heavy and volumetrically, very difficult to make work on an airplane.

90 mph is very slow for an airplane, revealing the limitations of the energy density of the system.

A cryogenic tank does not need to be heavy and the fuel is definitely not heavy. A compressed hydrogen tank is more heavy. I can't see what they use but I think it is cryogenic.

eci:

Lets see your numbers to back up your claims.

Perhaps you are confused, as you were when you confounded figures for the cost of running electric vehicles without equalising taxation.

Perhaps you would be more productively employed trying to move your website to some minimal standards of journalistic integrity, such as you and your writers declaring what financial interest you have in the shares of the companies you so uncritically boost, such as Tesla, rather than relentlessly trolling other more impartial sites.

The reformer is light and small, they have been made and used for decades. It has been done for more than a decade by Daimler in the NECAR program and even drove across the U.S.

Davemart as usual, full of personal attacks, but absolutely nothing of substance about the topic at hand.

You make some good points, Mahonj. Electric nosewheels are a recent innovation that appear to have commercial potential. The extra weight is justified by taxiway fuel
savings. There are some experimental propulsion hybrids, but extra mass that does not perform throughout the flight regime is inefficient.

The DLR HY4 has two fuselages, dual empennage, and one additional motor nacelle. There is no way around the fact that this increases the parasitic drag and construction cost vs a more conventional arrangement, which is one of the reasons why it is seen so infrequently in aircraft design.

There are some notable aircraft from Bert Rutan that have used a similar configuration, but in the evolutionary tree of aircraft design, it is not a branch with many progeny.

No doubt DLR chose this design because it provides extra volume for fuel
storage, but the performance specs speak directly to the viability of the concept.

If there were massive fuel cost savings, the low performance might be justified, but H2 fuel stations costing $2.5 - $4 million each, that is very unlikely to be the case. Except for training only use cases, or well-defined milk runs, lack of infrastructure will cripple H2 as an aviation fuel.

Regarding H2 fuel cost, here is a number for you Davemart. I was at Harris Ranch yesterday, where First Element has recently installed a hydrogen fueling station. Retail cost of H2 is $16.49 per kg.

Directly across the street, I refueled 200 miles additional range from the Supercharger for $0 (the fee had previouls been included in the purchase price of my car)

There is, by the way, also a Tesla battery swap station at that site. If you want that really fast refuel event, you can get it. It doesn't appear to get much use. Apparently after three hours of driving, most people would prefer to walk over to the fine dining restaurant and for about half the price of a swap, eat a premium steak dinner while the hoss feeds at the Supercharger trough.

Over the 15 year lifespan of an FCV (the 10,000 PSI fuel tanks are life-limited) a once per week 4 kg fueling stop at Harris Ranch ( ~12,000 miles per year) would cost $51,480. The first three years will be paid by Toyota or Hyundai, discount $10,296.

$41,184 H2 vs $0 Supercharger. There are some numbers for you Davemart.

It is too slow and the passengers can't talk to each other.

It looks like conjoined twin sailplanes, right down to the T-tails.  That is probably what it is, saving the cost of designing a new fuselage.  Only the wing center section needs to be new.

It also seems to have a very high wingspan, this making it large + it looks expensive to build.

You need the long wingspan to get the L/D required to fly 4 passengers on just 80 kW.

I'm always interested to see a good link, so thanks for posting SJC. I do have to ask though, without intending to be snarky in any way, what is the relevance of a link to a 13 year old story? ("DaimlerChrysler" was my first clue).

If no one has followed up and made a commercial vehicle in 13 years, how is that an indication that this technology is viable now?

Wiki> One of the potential drawbacks of using high concentrations of methanol (and other alcohols, such as ethanol) in fuel is the corrosivity to some metals of methanol, particularly to aluminium.

So don't spill it on the airplane wing while fueling. (the stuff on the wing surface would not be the problem. The stuff that seeps into the cracks and crevices from a spill would be the problem).

Toxicity does seem to be a problem, because it's possible to inhale fumes or absorb enough through the skin to cause blindness or death:

http://www.thetruthaboutstuff.com/pdf/(107)%20Kavet%20Methanol%20Vapor%20Toxic%20Dosage%20for%20Man.pdf

It may seem possible to fit high pressure H2 tanks in the tail boom, but only until you actually do some weight & balance calculations. Then it becomes clear that it's a total nonstarter.

Even if you were to temporarily suspend rational thought and imagine it possible to make the tail boom into, or contain, a leakproof 10,000 psi pressure vessel (which weighs over 100 lbs to contain 5 kg of fuel) there is a really good reason no real aircraft stores fuel in the tail boom. Depleting the fuel over the course of the flight would unbalance the aircraft.

I admire your enthusiasm Roger, but kindly suggest you spend less time reading fantasy fiction, and more time reading science and engineering textbooks.

It's just not helpful (to you, or anyone else) to repeatedly demonstrate that you haven't the slightest idea how the things you are suggesting would really work.

Stacks and reformers have improved since 2002. Daimler ran reformed methanol for more than a decade successfully. This has been done, it is proven technology.

Roger, i think you live in a lala land of your own creation. Instead of trying to "educate" people on a topic which you clearly do not understand yourself, why not spend your time getting a real education first, so that you have some credibility, and real value?

Have you ever even seen a hydrogen tank up close? Have you ever seen a cutaway of a hydrogen tank? What is the thickness of a typical 10,000 PSI hydrogen tank? (or for that matter even a 5,000 PSI hydrogen tank). None of this matters if you live in a fantasy land where reality is anything that springs from your keyboard.

But in the real world, it matters quite a bit.

I never said the oil industry has prevented reforming.