Hydrogen powered flight

[KungFooBob]

That truck is never gonna fly! Surely not.

Maybe the truck identifies as an aircraft, suggesting it's never going to fly is hate speech!

[Taff]

I've seen photo's of this test bed with a different prop fitted but it had power cables running to it presumably from a gert big generator.

This is a bit different here because it's running from batteries fitted to the truck bed.

[Mr. Dazzle]

AFAIK someone is building / gonna start building a Hydrogen powered Islander at Cranfield. My house is pretty much dead in line with the Runway there so I'll keep an ear out for the unusually quiet plane.

[Taff]

AFAIK someone is building / gonna start building a Hydrogen powered Islander at Cranfield. My house is pretty much dead in line with the Runway there so I'll keep an ear out for the unusually quiet plane.

So there is..
https://www.islesofscilly-travel.co.uk/ ... ropulsion/

I'll be interested to follow the progress on this one, I was the safety engineer in the MOD Highlander & defender project team a few years ago.

[Taff]

I'm not sure that you'd hear very much difference tbh because the vast majority of the noise at take off is from the prop rather than the engine.

[Tomcat]

The proposed planes look really odd to me, 'cause the wings are a long splindly shape. They'd keep the hydrogen in pressure tanks at the back, rather than in the wings like they do with jet fuel, thus leaving you free to optimise the wings just for flyin'. I.e. they don't have to be tanks too. Note the lack of windows at the back...

Long spindly wings are of course the focus of the manufacturers at the moment, as the favoured way to minimise drag and improve fuel burn. It's tolerable with liquid fuel as that sits in the wing cavities, though you'll lose some space for the folding mechanisms. Offsetting that you shouldn't need to carry as much anyway as you burn less if you have less drag, and reducing weight reduces drag again, so it's a virtuous circle.

But the problem of H2 as an aviation fuel is less the shape of the wings and more how to carry the stuff, period. You can't liquefy H2 below 33 Kelvin which is pretty damn cold, and a critical pressure of approx 200 psi. You can forget about carrying it as a gas. The storage and transfer of LH2 would present some pretty enormous challenges and I wouldn't like to be the one who had to write the risk assessment. You can forget about wing tank storage as well, you'd need large pressure vessels in the belly of the aircraft, just below where the passengers were sitting, cutting cargo revenue space and god forbid the slightest leak. At least it's fairly hard to ignite aviation kerosene. Airbus seem to suggest in that pic that tanks will be carried at the rear of the fuselage, well that's not cost free either because passengers can't sit there.

Then you have the "green" credentials. Splitting water into O2 and H2 is hugely expensive in terms of electrical power. Green, yes, but hugely expensive. Did I mention the expense? Most H2 production these days is done by splitting methane, which creates H2 and that well known non-greenhouse gas CO2.

If we can move to an economy of 100% renewable electricity with sufficient capacity (given that a lot of cars will be demanding it too) than perhaps H2 is a viable fuel for domestic heating. But I certainly don't see it having any place in aviation.

[Horse]

My house is pretty much dead in line with the Runway there so I'll duck

ftfy

[Taff]

If we can move to an economy of 100% renewable electricity with sufficient capacity (given that a lot of cars will be demanding it too) than perhaps H2 is a viable fuel for domestic heating. But I certainly don't see it having any place in aviation.

This seems to be a common view, but there is a hell of a lot of money being spent by many different projects to try and get it to work.

At our last count, we identified 17 projects, some of them may be startups that have little hope of achieving much before running out of money but that isn't the case for others. I suppose only time will tell

[Mr. Dazzle]

We need another cold war, people would consider any old mad shit back then!

https://en.wikipedia.org/wiki/Lockheed_ ... prov=sfla1

[Taff]

Airbus have just announced that they are still moving forward with hydrogen fuel cell and it sounds like they're dropping a pretty penny into it.

Airbus and MTU Aero Engines to create a ... nn6Fp3sJgd

Hydrogen fuel cell technology generates electricity through an electrochemical reaction between hydrogen and oxygen, producing only water vapour as a byproduct. This would eliminate inflight emissions of carbon dioxide (CO2) and nitrogen oxides (NOx) and contribute to reducing aviation's climate impact.
In March 2025, Airbus announced that it was focusing efforts on a fuel cell fully-electric propulsion system. The results of the fuel cell prototype and powertrain testing, as well as research into complementary technology such as cryogenics, supported the viability of this technology.
MTU Aero Engines has also reached some important milestones over the past months: the design for the company’s Flying Fuel Cell has been nailed down, stack manufacturing for the demonstrator has started, the eMoSys electric motor was successfully tested for the first time, and the first test cell went into operation in Munich

[.....]

Hmm hydrogen and flying vehicles was tried a few years ago, it didn't end well.

Whatcouldpossiblygowrong

[Taff]

Hmm hydrogen and flying vehicles was tried a few years ago, it didn't end well.

Whatcouldpossiblygowrong

Pretty much anything that can go wrong in any other aircraft.
Think Nimrod and Concorde as just 2 examples of what happens when you have a fuel leak.