It's disappointing that SST died off the way it did. In the 1960s, the 747 was originally designed as a stopgap between subsonic and supersonic, which was viewed as the next inevitable step.
Unfortunately, in a hamfisted effort to study the impact of sonic booms, the air force created so many over Oklahoma City that the government lost a very large lawsuit over the damage done to nearby buildings. Regulations ensued, and that effectively stunted any efforts to minimise the sonic boom in commercial applications.
I'm hopeful this can kickstart a new effort to renew SST and scale it to where it was more cost effective than the Concorde tried to be.
Sonic Booms wern't the only problem. It's hard to get around the cost element since jet fuel is a significant chunk of an airline ticket and SSTs are necessarily going to burn a lot more of it. Ultimately people largely chose to save the $1,000 and take the extra 3 hour penalty to their trip. Even for people willing to pay more you have to consider competition like the luxurious Emirates A380s that give you a small bedroom for the trip vs. the coach seats on the Concorde.
It's probably worthwhile to continue researching the space, but it's hard to see the economics working out--especially outside of small business jets. There just aren't that many people who care enough about extra hours that they can already travel in a fair bit of comfort if they're willing to pay for it. This is especially true if the design can't handle truly long distance travel like trans-Pacific.
Although it's not quite the same thing, I'd observe that British Airways has even cut back on its business class-only flights from London to New York. There just aren't that many people willing to pay thousands of dollars to either save a few hours or to travel in more comfort for a few hours.
Perhaps in the near term it only makes sense for business jets, but it is a step forward. It isn’t money down the drain and the research will pay future dividends.
> The United States spent $20 billion for air conditioning during the Afghanistan and Iraq wars.
Do you think this is some kind of luxury? Have you got any idea how hot it gets in an operations room tent in Afghanistan? And some of those tents are hospitals.
As much as I like what SpaceX are doing, I'm personally dubious about the idea of tens or hundreds of large scale ballistic rocket launches every day and their affect on the atmosphere, purely for consumer travel.
The thought of making a colander out of our ozone and ionosphere sends shudders down my spine.
They are LOX/kerosene so it's not as bad as hydrazine or something. And it's less fuel for a suborbital lob and subsequent braking burn than for LEO. And a good portion of the journey is unpowered ballistic drift.
But yeah, it probably isn't ideal for the atmosphere.
SpaceX are using methane for BFR point to point, not kerosene. Burns cleaner, and they're planning on synthesizing it eventually like they need to do for Mars.
Although I suspect that long-term, if you're synthesizing your fuel, you're better off using hydrogen instead of methane. Structural mass is generally higher if you use hydrogen, but there is a performance boost especially at higher velocities. And you avoid the inevitable energy loss from the Sabatier Reaction. And generally better for the climate than methane, particularly if you're running fuel-rich.
From a conservation of mass standpoint, synthesizing methane would be better for the climate. The stored fuel represents temporarily sequestered carbon. The exhaust, whether the engine runs rich or lean, only represents carbon that was in the atmosphere before the Sabatier reaction was run. However, the total size of the launch vehicle market renders these speculations superfluous, for now.
The problem isn't just carbon mass (i.e. CO2 in the atmosphere), but the fact that methane is a much stronger greenhouse gas than CO2 per unit carbon.
The total size of the launch market today is infinitesimal (~100 launches per year and vast majority less than a tenth the payload capacity of BFR). But BFR is being built to change that by orders of magnitude. Long-haul point-to-point transport of people means potentially hundreds of thousands to millions of flights per year. Long road to get there, though, and the primary obstacle may just be the incredible airline safety record (to make it close, you probably need to include lifetime saved by making the trips shorter).
It's not a stronger greenhouse gas than CO2 when it's sitting in a tank, and it's not a stronger greenhouse gas when it's emitted as hot, reactive exhaust into the atmosphere, where it is immediately reduced to CO2, CO, H2, H, H2O, HO, and so on.
But, like I said, premature and superfluous, even though we should still do our accounting carefully, and not rely on "OMG methane!" as the guiding principle of our thinking.
Hydrolox will always be a more efficient fuel, but it's a nightmare to store and manage, and destructive to engine components, fuel lines, storage tanks, and, well, everything it touches.
It may be tough to have a reusable hydrolox rocket that's efficient from a total cost of ownership perspective.
I think we should consider the cost benefit analysis and maybe it makes sense to mandate that boosters throttle back when transiting the ionosphere. Especially if we are going to increase launches by a factor of ten or more.
Boeing had a competing transsonic design that lost to the 787. We hit $4/gal for gas during planning and airlines were interested in operating costs. Not shaving 90 minutes off an intercontinental flight.
As long as airport transportation and security continues to be a dog and pony show, that wastes more of my time then the flight does, I'd rather fly subsonic. Hell, I'll take one tenth of the delta between the two tickets, and splurge for extra leg room and a bottle of wine to see me through the flight.
with carbon emissions rising, I don't think a supersonic jet is something earth needs... I really wonder why Nasa invests in that. Is there some other research to be made on that prototype ?
1) The whole point of Interstellar is, yeah, if you're facing an existential threat, more farmers isn't going to help you much.
2) Farming is one of the biggest contributors to climate change and perhaps THE largest contributor to humanity's impact on the environment.
We probably need to eliminate most farming and replace it with a synthesized vegan diet (i.e. grown in vats, processed to reintroduce texture, etc) if we really care about protecting the environment.
We can (haha, farming), but it's much less efficient than synthesis (i.e. photovoltaics to produce electrolyzed hydrogen/methane which is then fed to hydrogenotrophic/methanotrophic bacteria that produce protein, starches, fats, etc), especially for protein production.
And it competes with nature for land and resources, especially water. And the need to keep pests at bay also causes big impacts. As does the run-off.
If we're imagining technology advanced enough to vat-grow vegetables (and social controls strong enough to make everyone eat them), we might as well just imagine better runoff control, better land usage, and low-toxicity pest and herbicides.
We already do eat vat-grown stuff. And I'm mostly talking about staples, which make up the vast majority of farmland. For anything mashed or made into flour or oil or powder, there's basically no fundamental difference between it being made in a vat versus a field. Whole, unprocessed vegetables like lettuce, etc? Well, that corresponds to a small fraction of farmland, and it also grows great hydroponically. Don't need to grow that in vats.
you must be joking. A lettuce which has grown in some backyards, with time and sun (and a lot of fight against various insects, true) tastes so much better.
But maybe your hydroponics are better than mine.
I'm all for optimizing farming if it's possible but I don't want any compromise on quality (taste, nutrients, whatever).
We don't need farmers. We've had too many farmers for the last 100 years. That's still going the way of consolidation and increasing automation. Engineers on the other hand are in high demand.
I saw the movie, but I missed the reference. My comment applies to the guy in the movie. He needs engineers too, not farmers. You don't raise agricultural output with more hands, you raise it with better tech.
You can make a supersonic electric jet (particularly with lithium-air batteries), or use fuels synthesized using electricity (i.e. hydrogen). It doesn't necessarily need to be a net emitter of carbon.
The intent behind my comment was not clear : I dream about stuff which is not frivolous in my opinion. I'd love to see economical nuclear fusion, 2 liters per 100km cars, advanced cancer understanding, interstellar travel. All these things point towards, I believe, a better future (or at least a future with a bit more hope). A supersonic jet doesn't like (for my very novice eyes) a step in the direction of my dreams, hence my question : is there something in it that I should know.
Perhaps there's military applications of their research, so they might do this to get more funding. And once they get more funding, they can spend it elsewhere (or not).
Electricity production is the biggest chunk of greenhouse emissions, accounting for 29% while transportation accounts for 21% [0]. Within transportation, emissions from airplanes only account for 9%. Extrapolating, airplanes are then calculated to be responsible for about 1.89%. On the other hand, emissions from vehicles and trucks emit 17.4%.
Applying Pareto's rule, we're better off focusing our efforts on decreasing emissions on electricity production and vehicles.
Aerodynamics, probably. Also, at that geometry, if the window were to provide any view forward, it'd need to be enormous.
A full-sized plane would probably have some front-facing windows, but I'd expect most of the visual approach to be done by instruments anyway. In order to have a view of the runway during landing, the Concorde had an enormous and heavy movable nose.
I wouldn't be surprised if it's a thermal issue. Front facing windows on supersonic aircraft get extremely hot. They probably figure they can do better with good camera/video setup instead. Or maybe the pilot wears VR goggles attached to an array of cameras around the plane so he gets a virtual transparent cockpit.
Also, to properly investigate something, it's usually better to investigate only one thing, not a combination of various different things that,with luck, means something.
Every image of this plane has a so-called "normal shock inlet," similar to the kind you see on an F-16, for example. These inlets are limited to the low supersonic range. (Mach 1.4 is really pushing it.) So, it's very unlikely that this is a thermal issue, especially given that the F-16 cockpit seems mostly conventional.
Far more likely is that abrupt area changes cause discrete shocks, each of which could merge into the "sonic boom" that the demonstrator is designed to alleviate. However, a simpler way to understand it is that, from a practical point of view, you basically want to be flying a needle to reduce the boom to its minimum possible volume.
I hope that nose is really light. Reminds me of the X-3 Stiletto which, from what I read, has been called an awful plane to fly (My intuition would say that its due to inertial characteristics, same reason the F-104 was so dangerous to fly).
It would have to be. Look how far back the nosewheel is. That nose is going to be like a baseball bat when this thing is taxiing around.
It's so comically long that you kind of want them to put a hinge on it way back at the cockpit so it can swing upright and let the pilot see where he is going when he's on the ground.
That wouldn't solve the giant club problem. Or you'll have the disorienting sensation of turning the wheel and having your POV swing sideways instead of pivoting. Possibly barf inducing since your body would be pivoting.
Ugh. The X-30! What a boondoggle! Nobody had any idea how to get that done. In every aero/astro engineer's undergrad fluid dynamics class, they teach you about heat addition to subsonic and supersonic flows. The biggest takeaway is that adding heat to a moving fluid destroys total pressure (aka stagnation pressure), the measure of useful work a fluid can do. The amount of total pressure destroyed depends on the amount of heat and the flow velocity. Half the job of a diffuser and/or compressor is to raise the pressure of the incoming flow, but the other half is to slow the flow down so that heat addition can be done without destroying too much total pressure. The very idea of "supersonic combustion," the "sc" in "scramjet," is antithetical to engine efficiency.
At some point,even a theoretical scramjet becomes a drag-producing device, instead of a thrust-producing device. Real scramjets will always crap out long before orbital velocity, which is around M=30.
To end on an optimistic note, dream of a rocket-based combined cycle engine, instead. They may or may not ultimately be viable as SSTOs, but at least there's room to dream, there!
I might be misunderstanding your suggestion, but a rotating launcher will have somewhat absurd structural stress (and be generally more dangerous) compared to a linear accelerator.
Perhaps someone with more experience can answer this question: is this an exceptionally large contract ($247 million)? The article implies that it covers the plane and its delivery, not the whole research project.
Can someone fix the title please? It uses X-Plane in the singular 'X-Plane construction begins' rather than the title from the article which is more clear about this being the newest among many explains over the years.
Maybe something like "NASA begins construction of new Super Sonic test plane"
Thanks! And thank you for deleting this as well. There was no need for my comment to stay open to discussion once it was addressed. No need to give us all more space to go down a rabbit hole.
Note the lack of front window. A periscope was installed at the last minute at the behest of a sponsor, (much to the chagrin of Lindbergh) but there's no evidence that it was ever used.
Interesting. I can't find any sort of artificial horizon, but i suspect the two "spirit levels" at the bottom (T shape) serve much the same purpose.
Given that it was an ocean crossing he would probably be watching the airspeed, altimeter and compass for most of the journey anyways (instrument flight rules?).
74 comments
[ 2.9 ms ] story [ 138 ms ] threadUnfortunately, in a hamfisted effort to study the impact of sonic booms, the air force created so many over Oklahoma City that the government lost a very large lawsuit over the damage done to nearby buildings. Regulations ensued, and that effectively stunted any efforts to minimise the sonic boom in commercial applications.
I'm hopeful this can kickstart a new effort to renew SST and scale it to where it was more cost effective than the Concorde tried to be.
Although it's not quite the same thing, I'd observe that British Airways has even cut back on its business class-only flights from London to New York. There just aren't that many people willing to pay thousands of dollars to either save a few hours or to travel in more comfort for a few hours.
https://www.huffingtonpost.com/2011/06/21/air-conditioning-m...
Perhaps in the near term it only makes sense for business jets, but it is a step forward. It isn’t money down the drain and the research will pay future dividends.
What does that have to do with the discussion at hand? I am struggling to see the relevance.
Do you think this is some kind of luxury? Have you got any idea how hot it gets in an operations room tent in Afghanistan? And some of those tents are hospitals.
I was only trying to show how little the research costs in the big scheme of things.
The thought of making a colander out of our ozone and ionosphere sends shudders down my spine.
But yeah, it probably isn't ideal for the atmosphere.
Although I suspect that long-term, if you're synthesizing your fuel, you're better off using hydrogen instead of methane. Structural mass is generally higher if you use hydrogen, but there is a performance boost especially at higher velocities. And you avoid the inevitable energy loss from the Sabatier Reaction. And generally better for the climate than methane, particularly if you're running fuel-rich.
The total size of the launch market today is infinitesimal (~100 launches per year and vast majority less than a tenth the payload capacity of BFR). But BFR is being built to change that by orders of magnitude. Long-haul point-to-point transport of people means potentially hundreds of thousands to millions of flights per year. Long road to get there, though, and the primary obstacle may just be the incredible airline safety record (to make it close, you probably need to include lifetime saved by making the trips shorter).
But, like I said, premature and superfluous, even though we should still do our accounting carefully, and not rely on "OMG methane!" as the guiding principle of our thinking.
It may be tough to have a reusable hydrolox rocket that's efficient from a total cost of ownership perspective.
http://www.businessinsider.com/earthquakes-fracking-oklahoma...
1) The whole point of Interstellar is, yeah, if you're facing an existential threat, more farmers isn't going to help you much.
2) Farming is one of the biggest contributors to climate change and perhaps THE largest contributor to humanity's impact on the environment.
We probably need to eliminate most farming and replace it with a synthesized vegan diet (i.e. grown in vats, processed to reintroduce texture, etc) if we really care about protecting the environment.
And it competes with nature for land and resources, especially water. And the need to keep pests at bay also causes big impacts. As does the run-off.
you must be joking. A lettuce which has grown in some backyards, with time and sun (and a lot of fight against various insects, true) tastes so much better.
But maybe your hydroponics are better than mine.
I'm all for optimizing farming if it's possible but I don't want any compromise on quality (taste, nutrients, whatever).
For a start we could just avoid wasting so much :
https://en.wikipedia.org/wiki/Food_waste#Global_extent
https://www.youtube.com/watch?v=_E792RxIpnU
Applying Pareto's rule, we're better off focusing our efforts on decreasing emissions on electricity production and vehicles.
[0] https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emis...
A full-sized plane would probably have some front-facing windows, but I'd expect most of the visual approach to be done by instruments anyway. In order to have a view of the runway during landing, the Concorde had an enormous and heavy movable nose.
I would opt for much simpler camera, an already-proven ILS and windows that allow the pilot to look down on the side of the plane.
The fewer things to go wrong on a brand-new design, the better.
Far more likely is that abrupt area changes cause discrete shocks, each of which could merge into the "sonic boom" that the demonstrator is designed to alleviate. However, a simpler way to understand it is that, from a practical point of view, you basically want to be flying a needle to reduce the boom to its minimum possible volume.
It's so comically long that you kind of want them to put a hinge on it way back at the cockpit so it can swing upright and let the pilot see where he is going when he's on the ground.
At some point,even a theoretical scramjet becomes a drag-producing device, instead of a thrust-producing device. Real scramjets will always crap out long before orbital velocity, which is around M=30.
To end on an optimistic note, dream of a rocket-based combined cycle engine, instead. They may or may not ultimately be viable as SSTOs, but at least there's room to dream, there!
This is the later phase of the NASA’s Quiet SuperSonic Technology Preliminary Design, or QueSST Project.
Can someone fix the title please? It uses X-Plane in the singular 'X-Plane construction begins' rather than the title from the article which is more clear about this being the newest among many explains over the years.
Maybe something like "NASA begins construction of new Super Sonic test plane"
That plane doesn't look very pilot-able. How can the pilot see forward? I know it's an early render, but still ...
[1]https://en.wikipedia.org/wiki/Droop-nose
https://airandspace.si.edu/sites/default/files/styles/slides...
Note the lack of front window. A periscope was installed at the last minute at the behest of a sponsor, (much to the chagrin of Lindbergh) but there's no evidence that it was ever used.
And that was before cameras and in-cockpit AR!
Given that it was an ocean crossing he would probably be watching the airspeed, altimeter and compass for most of the journey anyways (instrument flight rules?).