Rear center fuel tank adds roughly 20k liters and extends range by 1k NM | Hacker News Reader

Rear center fuel tank adds roughly 20k liters and extends range by 1k NM

airbus.com

36 pointsr2sk5t59 comments

> flight times of up to 22 hours

Making flight connections is never fun, but this sounds absolutely brutal.

I'd love to visit Australia and SE Asia but am hesitant with those long flights. I'd probably be fine with layflat seats but those are well beyond what I'd ever consider paying for an airline ticket.

Would make sense to offer packages with lay-flat seats in shifts (possibly formally/informally for people on the same ticket).

You could pack a lot more in if you sedate them and put them in racks like they have at the morgue. TBH I'd sign up for that on a long flight if the sedative recovery wasn't bad.

Next stop Phlosten Paradise.

This is exactly what I was thinking of when I wrote it down ;)

Just like The Jaunt by Stephen King. "It's longer than you think, dad! ...about 22 hours."

Ah yes, the B.A. Baracus method! I'd use that!

Especially on the same routes where you’d think about using this kind of airliner...

https://www.airnewzealand.com/economy-skynest

You just know this is going to be 2-3 times the price of an economy seat, which means you're going to buy the economy seat anyway. In flights, price beats everything else.

I think this is an ancillary specifically for economy class passengers—you pay a certain amount to reserve a 4-hour slot on a bunk or something. I have no idea, but my guess is economy + nap slot would still come in well under the cost of a business seat. Plus they can sell those same 6 berths what, 4 or 5 times over in the same 22-hour flight?

If I recall correctly they’re not certified for use during taxi takeoff and landing, I’d imagine due to orderly-evacuation kinds of requirements.

You can play the points game and win - Singapore biz from US west coast booked a year in advance is within the signup bonus amount :)

Many of colleagues do this all the time, usually via the Middle East. I did it before; it sucks but with enough gin tonic and melatonin it goes by in with too much pain.

I've traveled UK to Australia a few times. Not nonstop, but with stops in SE Asia, basically 2x13 hours plus a few hours airport time.

It sucks, but you get over it because how else are you going to get there? If you don't suffer blood clots or something, it isn't really actively dangerous.

>2x13 hours plus a few hours airport time.

That sounds like pure torture

Isn't everything, really? A dentist's appointment for example. It has an end, and then you're glad you had the courage to go through it.

The longest I've spent in a dentist's chair is perhaps an hour, when I had braces as a teen.

Being cooped up in a metal tube for 13 hours, knowing you had to do the same thing tomorrow, and then the same thing two more fucking times on your way home, is not worth any vacation to me.

Then don't do it for vacation. A resort in Australia is no more valuable to you than one in Florida (if you're in the US). Do it for something more meaningful.

> how else are you going to get there?

Sailing would be more fun, IMO. Might take a quarter or half a year though.

Living in Australia, and travelling to Europe last Christmas as a family of 4, I really wanted to get the direct London to Perth flight, but connecting flights didn't line up. Being able to do Melbourne or Sydney would be great. Not needing to deal with connections, and cutting 6+ hours off the total travel time sounds amazing, possibly getting us there a day earlier, meaning more time for Greggs vegan sausage rolls.

Yeah but the idea is most folks will fly direct.

Also bad for fuel economy (and/or take a hit on cargo/pax/luggage carrying capacity): You have to take off with all that fuel even though you only need X / hr. Increased weight = more flying at a lower altitude (+ air resistance) until the fuel burn makes it safe to fly higher.

On shorter flights, you still have the weight impact from that empty tank and its infra. If they had to make a bump out on the fuselage, you have a permanent aerodynamics hit.

It's like permanently attaching a cargo carrier to your vehicle to carry more fuel. Fewer fuel stops, but more burn per mile. Can make sense in some situations.

The study of breaking up long-haul flights for reduced fuel burn is usually called: "Intermediate Stop Operations"

But it may allow operation of more routes without the need to refuel at both ends. That can be logistically interesting, paticularly going forward in a world of fuel crisis and uncertainty. Being able to deliver people in and out of Cuba without having to refuel in that country would be a market niche.

Assuming you can regularly land with your fuel tanks half-full. You could overbuild everything to support that, but usually airlines don't want to pay for a niche design to support that. I'd bet military aircraft do get that treatment though.

It is actually rather common. Many airlines running shorter flights will not refuel at every stop. It saves time on the ground, which can be more valuable then fuel.

rather common amongst (ultra)-long voyages?

You're still cutting a take off and landing so I can't imagine it'd be too hard to break even for flights where this increased capacity is helpful.

Not only do take-offs spend large amounts of fuel; the fact of a landing and the servicing and refueling in the airport also cost the airlines.

Not having to land but instead having to carry some extra fuel while the engines work in their most efficient mode, and the air drag is low at a high altitude, should make airlines money. Else they won't try that :)

Not just cost, but that limited airport "slot" represents (a slice of the) significant carbon emissions from building/operating the airport.

So even if you only care about carbon emissions, it can still make sense to skip the stop even if it causes slightly more total fuel burn.

Semi-tangential, but this is why free markets are much more efficient than armchair experts.

Armchair experts won't correctly estimate all of these incidental costs nor the value of the saved time and overhead for everyone involved.

It's basically the business model for some airlines like the Icelandic and middle eastern ones. Hub in the middle so you're not paying (potentially extra) staff to rest on an aircraft and/or hotels at each end. Be at home more rather than an out-station. Fuel up more where its cheaper. Do some "scissor" routing. Fly cheaper/less specialized aircraft. Not as easy for Qantas to get all those advantages. Cargo airlines do the same to carry more cargo.

It's okay that different businesses specialise differently. Icelandic Air can do the two short hops and Qantas can focus on the super long nonstop routes, they're both valid. When companies in an industry become carbon copies of each other, they race to the bottom and the industry rapidly enshittifies.

At some crossover point, the reduced fuel carrying (and max capacity requirement) makes up for the additional takeoff+landing. When we're talking ultra-long-haul, constantly fighting against more gravity due to incr fuel weight adds up to a lot of cost/burn.

A compromise option is a technical stop[0] where the plane lands to refuel but passengers don't have to transfer to another aircraft (and often don't even have to deplane). I've never experienced one of these but it sounds way less annoying/stress-inducing than a connecting flight.

[0]: https://travel.stackexchange.com/q/1598

Does it actually take 22 hours for a commercial airplane to get to the diametrically opposite point on the globe?

900 km/h, 20,000 kilometers. Yep!

22 hours is a very long time to be in a plane. But, being able to skip a stop in a 3rd nation is likely worthwhile for many. Depending on the routes, it will likely reduce the overall travel time significantly and a meaningful amount of time in the air.

What are the economics of connecting flights? I'd imagine that max flight time isn't the only factor; hubs allow people to move around via connecting flights in a way that might not be economically acceptable if all flights were direct.

These ultralong flights will surely only be used regularly on routes with enough traffic, like London/Sydney.

Although they could also run intermittently to different places. Like London/Sydney on Monday, London/Melbourne on Tuesday... Which one brings in more money? I really have no idea. If you do it like this you can serve more people with direct flights, but they can't pick any day they want. I was once on a scenic long-distance train for some reason that didn't run every day due to low usage — Wellington to Auckland, I think? Normally you'd fly.

Seattle to Joburg is brutal. It's ~23 hours of flying with a lay over somewhere like Dubai. As much as a 23 hour flight sounds terrible, it's hard for me to express how much dread I felt getting back onto a plane right after a 13 hour flight. I'd rather just hunker down for the full day I think.

New A350's has better air quality, higher humidity and cabin pressure, and these long haul flits have less seats to reduce weight .. but it's still brutal.

> In addition, a new galley air cooling system will also be certified, which features lighter and more efficient refrigeration units for very long flights.

I wonder how they work.. considering outside air is way below freezing ar cruising altitude, I guess radiators?

Could the refrigerant be brought close to the plane's skin to cool it?

Or just… computer controlled air vents?

may not be worth the aero hit. Kinda like running a/c in a car at high speeds instead of opening the windows. Not sure where the crossover point is.

In my dreams, my ultra-advanced car would open the windows when braking to get two benefits in one.

  >In my dreams, my ultra-advanced car would open the windows when braking to get two benefits in one.

Or use those triangular vent windows / wing windows, as seen on old trucks and classic cars.

https://www.fastlanecars.com/blog/wing-windows-history-and-c...

https://www.ccjdigital.com/trucks/article/15749837/the-story...

You could quickly flip it open with a servo when braking, controlled by a differential thermostat so it only pulls in air when the outside isn't too much hotter than inside. I think you actually want a negative thermostat offset, because even if it's a couple degrees warmer you still get moving air.

Compared to rolling down the window you don't get the loud buffeting sound, it acts as a really good aero-brake, and it pulls in huge amounts of air. There's the downside that it will preferentially pull in air around intersections, where traffic pollution tends to peak due to braking and accelerating (EVs help but there's still brake and tire dust).

Love this honestly. It has definite "shitty project" potential...

Planes generally avoid braking. Many are equipped with explicit "speed brakes" and all can use their control surfaces to create inefficient aerodynamic configurations, but fuel is expensive so they avoid it unless there's a situation like getting cleared for a shorter approach than expected. Ordinarily, they plan a descent path which can be accomplished naturally with a lower than normal thrust. The standard is three degrees below horizontal. Of course they also activate all braking possibilities upon touching down, but you can't keep the fridge cold by cooling it only upon landing.

When cruising (most of the flight), smooth aerodynamics are extremely important, and you wouldn't mess them up just to keep the galley fridge cold. Example: whenever a plane has the landing gear out it burns 2-3 times as much fuel, because that's just how much it costs to not be smooth. That's why they retract the landing gear almost the moment the plane leaves the ground, and why a plane with its landing gear stuck has to return home (despite not being a serious emergency).

For cars not planes, but apparently you're an LLM so....

Am I? Uhhh, I mean, you're absolutely right! Honestly, that's load-bearing. It's not a bird, it's Superman.

Punchy sentences. Stupid metaphors. No substance. 100% pure LLM slop delivered straight to your retina.

Maybe the refrigeration is shared with the galley (food storage), and/or is only needed when the plane is on the ground?

Seems like the galley air cooling system is designed for cooling the equipment and food in the galley, not the general air supply for the passengers.

https://aviateai.com/efficient-galley-cooling-system-optimiz...

At altitude you can reject heat straight to the aircraft skin. Some designs run an internal heat sink on the ground and during climb, watch altitude, and only switch on the skin-exchanger coolant pump once outside is cold enough to cool the loop for free.

The reason it stays a refrigeration unit and not just vents is the ground case. Gate on a hot day, doors open, no ram air, warm soak: that's the worst case, and where the compressor has to work. One published point-of-use chiller design specs roughly double the load on the ground vs in cruise (order of 700 W vs 300 to 400 W per unit). So the vapor cycle is sized for the ground, and most of a 20 hour flight is spent in the regime where you barely need it.

And these aren't fridge boxes at each cart. It's a central vapor-cycle chiller cooling a glycol/water loop piped to air chillers at the galleys; the carts get chilled air. The heat comes off the condenser and goes to ram air, a skin exchanger, the cargo hold, or back into the ECS, depending on the aircraft. Which one the new ULR units use, Airbus hasn't said. For a 22 hour flight the interesting number isn't peak capacity, it's efficiency and weight in cruise, which is probably what "lighter and more efficient for very long flights" is pointing at.

Presenting raw LLM output as your own writing in a human-to-human context is rude and antisocial, not to mention incredibly transparent.

I was oblivious - how did you tell?

There are a lot of commas.

I didn't notice but this sentence feels like AI:

> Gate on a hot day, doors open, no ram air, warm soak: that's the worst case, and where the compressor has to work.

Was once on a flight sitting at a gate with a faulty ground air connection or something, and they weren't allowed to run the APU at the gate due to pollution. It must've been 40 degrees (Celsius) inside, at Singapore Changi, and they were delayed at the gate too. Everyone breathed a sigh of relief when we started moving and got air conditioning from the engines.

I think once bleed air is compressed to a suitable pressure it's hotter than room temperature, and has to be cooled down.

The Sydney / London flight most direct path cross Russia and that's already 17000km so probably it has to go south of Iran and that's another 1000km thus 18000km total.

The route Qantas has stated they will use (at least for part of the year due to weather and winds) actually goes northeast over the Pacific Ocean, over the central US/Canada, over the North Pole, and then into the UK from the north. It doesn’t go over Asia at all.

I like stop overs but I wish they counted toward flying time.

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