20hrs on a Qantas plane: the future of aviation or a fresh hell in economy?
theguardian.com
theguardian.com
If people need to travel long haul, this is the way to go.
I arrive at the station/terminal/depot, get put to sleep and loaded into a pod, then wake up at my destination. No fuss, no mess!
All the inconveniences go away and transport efficiency skyrockets.
Though I do worry that I may wake in the wrong place, given how airlines tend to lose baggage today - once we start treating passengers as cargo then we have to worry about all the cargo issues...
https://www.washingtonpost.com/travel/2022/08/16/craft-beer-...
But not a lot of options if I need to get to Indonesia or the Bahamas.
Or they lose track of your pod and find you a dried husk in a warehouse a few years later.
The folks at the airport bars sell a wonderful concoction called a "Long Island Iced Tea"
Don't let the name fool you; if you drink one 30 minutes before departure (and make it to the plane), you'll open your eyes just as the plane touches down :)
But still 20 hours ain't really that much, not even a full day.
Is it the airlines problem that people with problems book long haul flights?
With a rocket engine, reaction control system and ablative coating, the X-15 almost had more in common with a space ship than an airplane.
Like this image depicts: https://en.wikipedia.org/wiki/Qian_Xuesen#/media/File:Tsien_... (This sort of missile flight is sometimes called a Qian Xuesen trajectory, after the man who first came up with the idea.)
The basic physics are arrayed against you. Higher speed cruise flight already means you already fly at higher altitudes or the thermal and structural loads would be intolerable. Stall departure resistance isn't the issue. Get high enough, and you're no longer talking about cruising flight, you're talking about hypersonic glide that has been accelerated to hypervelocity by rockets (this is called point-to-point boost-glide). It has been looked at, and people are continuing to look at it. There is a whole loose industry coalition in the U.S. called "FastForward" that is interested in this topic.
Even the new supersonic plane in development, Boom, has a promised range that requires a a stop for transpacific flights.
Where do you get this from? I suspect you are talking about the Breguet range parameter, which is (M / SFC * L / D), where M is the cruise Mach number, SFC is fuel consumption per unit thrust, and L/D is aerodynamic efficiency.
Cruise L/D drops monotonically with Mach number until it asymptotes out to hypersonic waverider type figures (the well-known Kuchemann curve fit for supersonic L/D and the asymptoting to waverider values is illustrated at: https://aerospaceweb.org/design/waverider/design.shtml ).
SFC for gas turbines is extremely sensitive to cycle parameters and internal temperature limits, but generally well-designed gas turbine propulsion systems are going to beat ramjets until they hit thermal limits. Today's gas turbine technology is far more capable than the J-58 technology of the the A-12/SR-71 era. That said, SFC is still going to increase monotonically with cruise Mach number until you asymptote out to flatter slopes of ramjet and scramjet curves. (Edit: see the Isp illustration at: https://en.wikipedia.org/wiki/Specific_impulse ; Isp is the inverse of SFC).
So you are banking on the increase in M more than offsetting the increases in SFC and decreases of L/D. This is not going to support the case for increased efficiency in high supersonic (M >= 3) cruise. You could make the argument going full-on hypersonic waverider could "make sense" since the range cost functions plateau out, but that is still going to have a strictly lower overall range parameter than a supersonic vehicle. Kuchemann addresses this topic in his well-known text, "The Aerodynamic Design of Aircraft".
A naive Breguet range parameter perspective also fails to consider airframe mass penalties associated with flying faster (roughly, aircraft acquisition costs trend with aircraft unfueled weight), or that high aerodynamic efficiency is often at extreme odds with volumetric suitability for passenger & cargo carriage. Mass penalties will come from variable geometry, thermal management, Cg management, degree of compromise in structural efficiency for aerodynamic efficiency, etc. Let's say you manage to keep Breguet range parameter really high and fuel burn per seat-mile is acceptable. All the complexity and increased airframe mass of the faster aircraft is still going to make recurring costs to operate & maintain the aircraft really high.
The above also neglects boom, which you ideally want to minimize to maximize overland flight potential for your supersonic aircraft.
As per a previous comment I made: https://news.ycombinator.com/item?id=27386119 , if you're going to go in on supersonic civil flight, you likely want to be below Mach 2. Mach 1.4 - 1.8 might be the sweet spot when you consider all factors, assuming it makes any sense at all economically.
For the majority of air travel, we would be better served by making the airport experience much more streamlined and less shitty. And I say this as one who loves and works in high-speed flight.
Circa 1960 they imagined that supersonic military aircraft would "dash" when the mission required it but otherwise fly more slowly, then they realized the fuel economy of supersonic aircraft peaks around Mach 3. Something SR-71 class has good fuel economy at speed, but has horrible problems when it comes to (1) materials, and (2) taking off. The SR-71 was of course made of Titanium and dealt with (2) by taking off with as little fuel as possible and then refueling once it was up in the air -- an answer which isn't suitable for civilian use.
Also circa 1965 it was widely thought that SSTs would make airliners like the 747 obsolete quickly because they could make more flights in a given amount of time thus being able to pay the capital cost quickly. The US aimed to develop Mach 3 class airliners
https://en.wikipedia.org/wiki/Boeing_2707
and failed but the Europeans developed a slower airliner
https://en.wikipedia.org/wiki/Concorde
which was "successful" in terms of getting into the air but probably doomed in economics from the very beginning. The Concorde couldn't actually fly more flights per day than the 747 on the routes it flew on so it didn't get the capital cost amortization advantage that a faster plane might have gotten, and fuel economy was worse.
A more ambitious plane might require some crazy ideas like
https://venturebeat.com/offbeat/nasa-sideways-supersonic-pla...
to solve the takeoff problem.
https://theaviationgeekclub.com/heres-why-the-sr-71-blackbir...
Couldn't we, in theory, slingshot the planes into the air to achieve the same relative fuel burn rates ?
I think this only exists on aircraft carriers ?
The required release velocity would need to be so high that drag from air resistance (which increases with the square of velocity) would slow down the vehicle such that there would be no benefit.
However, it then raises the question: What are they doing on aircraft carriers and how is that different ?
https://en.wikipedia.org/wiki/Aircraft_catapult
... I assumed those had some fuel-use benefit, but perhaps their only benefit is shortening the runway ?
You could likely lessen fuel burn of a supersonic aircraft taking off (as you could with a subsonic aircraft) by accelerating it via a catapult of sorts, but you have to do so at acceleration levels tolerable to all passengers, which would make for a long, unwieldy catapult. Release speed is also obviously going to be very subsonic.
As I noted in a below comment, there isn't a way for this statement to be accurate without a lot more qualifications. For "equivalent technology level", Mach 2 cruise will beat Mach 3 cruise in passenger seat-miles per unit fuel burn, and below Mach 2 will be better still.
The extremely questionable economics of supersonic commercial flight were realized by technical people far before the 1960s US programs were terminated. Two excellent sources on this topic are by aviation historian Richard K. Smith,
https://www.jstor.org/stable/26802349 , with text freely available at: https://www.thefreelibrary.com/THE+SUPERSONIC+AIRLINER+FIASC...
and the book "High Speed Dreams" which also covers the 1990s HSCT era: https://press.jhu.edu/books/title/8516/high-speed-dreams
There's significantly more to the problem than just managing heat and "solving" takeoff.
I can walk around, find something to eat or read, people watch. Plug in a laptop and sit at a table that's reasonably comfortable to work on. Relocate somewhere quieter, or more interesting. See if I can find bathrooms that aren't slammed. Get my steps in / some exercise.
The struggle is real on those long flights when there's little respite from turbulence, though, to the degree that the service is constantly interrupted (or abbreviated), passengers can't get up to use the facilities, and everyone's too nauseous to sleep. I've been on a few where the seat belt light was lit up almost the entire ride.
or, you know, beer.
Ultra low tier services like spirit airlines shouldn't exist for flights longer than 4 hours. Ultra Economy seats for more than 10 hours might as well qualify as torture in some nations.
They don’t if you don’t fly them.
Consumers are wrong and actively bad for being willing to buy ultra low cost tickets on long flights. These people are wrong and regulations should exist to prevent their lunacy. We do this in many other industries where there would be a race to the bottom of regulations didn't exist. Water, transportation, electricity, why not airlines?
And others are rooting for security to remove them as quickly as possible so that they can get to where they’re going without additional delays.