Almost certainly, the airframes are the cheapest part.
Has anyone ever tried to build an airship using hydrogen both for buoyancy and fuel? My idea (almost certainly not new) is to fill it with enough gaseous hydrogen to give it a lot of lift to begin with, then gradually use the hydrogen for forward propulsion. It would be cool if the numbers worked out such that it was buoyant enough to rise to a great height to begin with, then gradually descend en route so as to be near the ground by the time the desired horizontal distance had been covered. An obvious problem would be clearing any obstacles in between. Absent that, the flight path could be almost vertically straight up to begin with, followed by a continual descent towards the destination.
I suspect another reason it wouldn’t work is the amount of hydrogen you take out causes a much greater vertical drop than the thrust provided by its combustion can offer in forward velocity. Does anyone know?
The interior is a complete one-off. They have stair access for the belly area so maybe there are hot tubs in there. Who knows.
The Hindenberg did not fare well with a hydrogen envelope, I doubt we will use hydrogen for lift in the future.
Still, the question is interesting so I took a stab at it.
A ballpark number for hudrogen consumption in an internal combustion engine is about .15 L/min per Litre of engine size. So a 1L displacement engine could be expected to burn about 9L per hour.
Let’s use the Hindenberg as an example. It was powered by four Daimler-Benz 88L diesel engines. Given the ballpark numbers above, that’s 792L per hour per engine, or 3162L of hydrogen per hour. The Hindenberg traveled about 84mph, so that’s 37.7L of hydrogen per mile.
The Hindenberg had about 200 million liters of hydrogen in it, so you aren’t going to deplete the volume of hydrogen by much. Perhaps a better way to look at it is how much lift you would lose as hydrogen is consumed. At sea level, 1L of hydrogen will lift about 1.1g. Call it 40g of lift lost for every mile traveled, or 40kg over 1,000 miles.
That surprised me. Assuming you don’t mind sitting under 200 million liters of flammable gas, it would be totally feasible to power the engines with the hudrogen.
Cool, seems like my intuition was completely backwards on this one. Many thanks. I agree that preventing fireballs is a greater problem.
They’re using Helium for lift but planning on hydrogen to run generators for the electric motors.
That seems hard to believe. Are you sure that isn’t liquid hydrogen or something?
Air is 21% oxygen. You need 2x the hydrogen to combust with that, though it looks like hydrogen ICEs rarely run at stoichiometric, and are generally ~2x leaner than that. So equal volumes oxygen and hydrogen, which means 0.826 L air and 0.174 L hydrogen for 1 L displacement. But the engine is running at >1000 RPM (the Hindenburg engines ran at up to 1350 continuous). So that’s 235 L/min–over 1500x your number.
The escape pods don’t come cheap either.
How do you spend $1B? By spending about $500M on designing a lot of one-off two-off gear, about $400M on buying 2 plus spares of each of those thousands of things, and about $100M each installing those things on 2 airplanes.
The non-recurring costs are what kills you. Same problem with most military gear. iPhones cost a LOT of money to design. But when you sell them by the hundreds of millions, the design cost amortized over all those units is a small increment per phone. If they only sold a couple thousand (like a military fighter), or a couple dozen (like a military submarine), or only 2 (like a VVIP transport), the same design costs exert a very different impact on final pricing.
Pharma is similar. It doesn’t cost much to manufacture a single pill when you sell lots of them. But when you spend billions per drug development effort and most of those fail to produce a salable product, each pill from a successful development effort has a big overhead to pay back.
Also, a considerable part of all that – in both hardware and software – has got to be upgradeable for at least 20 years after delivery.
I get it, but being a construction guy it just boggles my mind. Near as I can tell a 747-8i is about 15,000 square feet of interior space on 3 decks. So that about $66,000 a square foot assuming $1B a plane. It’s difficult to spend even a tenth of that on a non-flying structure, even the most elaborate high-rise.
As I understand it, the Trump negotiated contract was for around $2.5B for 2 planes (the original bid was $3.9 - Trump cut that with a reported savings of $1.4B - ). Boeing is now reporting a LOSS of $2B total over the contract value - so each plane is now at ($1.25B + $1B = $2.25B). So if your 15k sq.ft. number is accurate (and I have no reason to doubt it, these are big planes), we’re in the neighborhood of $150,000/sq. ft. And going up.
ETA: Numbers from here: https://simpleflying.com/new-air-force-one-jets-now-put-boeing-2-billion-in-the-red/#:~:text=You%20may%20recall%20that%20in,a%20cost%20of%20%243.9%20billion.
Aaaaaand they’re losing money on the O3b satellites, too:
Despite Boeing now under contract to supply 13 O3b mPower satellites rather than 11, and the work needed to upgrade five of them, Pinto said SES does not expect to spend more money on the constellation because of a risk-sharing deal with the manufacturer.
Boeing recently disclosed $315 million of losses on a satellite contract to meet life cycle commitments for an undisclosed customer. A source close to Boeing confirmed SES is this customer.
I’d almost feel bad for Boeing had their mistakes not been a direct consequence of their management strategy. And not killed hundreds of people along the way.
Like at most corps there are really two Boeings. The revolving door of vulturous VP and above self-interested predators moving from company to company, and the entire rest of the whole-career-at-Boeing pyramid below.
It’s appropriate to feel bad for the second group while hating the first group. Of course the first group is enabled by a comparatively small coterie of self-interested strivers in the second group, but that’s an accelerant, not a cause.
Cite back to dedicated thread on the latest commercial pilot outrage:
Gotta go to Singapore sometime!
https://www.cnn.com/travel/singapore-changi-airport-terminal-2-expansion/index.html
Very impressive. Especially when used only by the 10 people we saw in the vid. Add another 10 or 20K and it’ll be a bit more frenetic.
It’s going to need a missing children office because kids are going to wander off.
Interesting bulletin recently released by the AAIB (pdf): https://assets.publishing.service.gov.uk/media/6544b3089e05fd0014be7c9b/S2-2023__Airbus_A321-253NX_G-OATW.pdf
Looking at the photo in figure 4, one wonders how thorough the pre-flight ‘walkaround’ inspection was (the flight departed at around 11am, so well into daylight). Or are windows not part of such an inspection?
It seems the root cause of the issue was powerful floodlights being positioned closer to the aircraft than recommended by the floodlight manufacturer.