I know because my great uncle died flying the X-15 on an experimental flight , so it's always been an interesting story for my family.
Scramjet planes are faster than other non-rocket planes I would imagine?
Scramjets do need air, although something to consider is that the faster you go, the more air you get. So at high altitudes with very thin air, you can go faster to get more air. In fact you have to go faster (true airspeed) in thin air anyways even if your brought along liquid oxygen for your engine, because as the air thins your stall speed will go up.
The whole thing is a complicated system of equations. Engine capabilities and/or critical mach number (for planes designed for subsonic flight, like the U-2) of the airframe set an upper limit on how fast you can go. Air density decreases with altitude, increasing the stall speed (according to true airspeed, not indicated airspeed.) But for a given true airspeed, with increased altitude the temperature of the air drops, consequently dropping the speed of sound, which reduces the mach number. In subsonic planes as altitude goes up the stall speed and critical mach number eventually pass each other, beyond which your plane can no longer fly. The point of that intersection is known as the 'coffin corner'. In planes designed for supersonic flight passing the critical mach number isn't a problem, but eventually you'll reach a point where the drag on the aircraft is so great that the engines simply don't have enough power to overcome it. Increasing altitude reduces drag as the air gets thinner, but that only works for so long. Air speed inside the engines needs to be considered too. The airspeed past the turbine blades needs to be such that you won't get compressor stall. When you discard the turbine requirement, that's where things start to get interesting. A ramjet has no turbines, it compresses the air using the intake geometry. At full speed the SR-71 was actually producing most of it's thrust with a ramjet effect, most of the air going into the engines was not going through the turbines. The difference between a ramjet and a scramjet is that in a ramjet, the air inside the engine becomes subsonic again for the burn, but in a scramjet the air inside the engine remains supersonic. Scramjets could go really fast.
I think the hypersonic planes will all be drone munition delivery (or just munitions themselves) for a long time. Maybe some day they'll carry people but there's no supersonic aviation much less hypersonic and even then the piloting at speed will probably be all automated.
The big challenge is basically making sure that you mix your fuel with the air, combust it fully, and extract the energy before it flies out the back of the engine. Scramjets are the engines capable of this at the highest speeds.
So when you get to mach 6 you might as well be in space....
It's certainly a glider on reentry. Now, most speed records for planes are "in level flight" which would disqualify the shuttle during reentry. But if we ignore that it's interesting that the speed record for manned aircraft is held by a glider, and the speed records for RC aircraft are also held by gliders! https://www.youtube.com/watch?v=MoaWlKC3wIM
So as far as "Official" speed records go the fastest "airplane" is a Sr-71. Its technically the fastest manned air breathing aircraft.
There seem to be some semantic ambiguities between Aircraft, Airplane, Rocket, etc.
His flight was a bit... crashy. The Wrights managed a fully controlled powered flight first, but even then their "first flight" wasn't as far as Pearce's flight had been nine months earlier. And it also ended in a crash.
Typically the Wright Flyer is credited with "the first sustained and controlled heavier-than-air powered flight" or something similar.
If you add enough qualifiers you can be first at anything.
As a Brazilian (see previous comments about the Wright Brothers), I consider that an airplane:
* Is powered, otherwise, it's a glider;
* Can maintain level flight, otherwise, it's just "Falling with style";
* Can take off on it's own, assistance (RATO, catapults) is allowed for short take-offs (like from a carrier);
The Shuttle fails in all that in some point of the flight or another, Buran on the other hand, could be fitted with air breathing jet engines that allowed it to do all that.
I like Douglas Adams' description: The ship hung in the sky in much the same way that bricks don't.
Well, by that definition I think the X-15 isn't a plane - it required a B-52 mothership to launch after all. IMO it's hard to find a definition of "plane" that includes the X-15 but not the Space Shuttle stack (not the orbiter on its own - the full stack).
And on descent it was gliding, not under its own power.
The other popular case, the only lost ship was also similar to the bad MCAS system in the Boeing 737max, the pilot forgot to turn off the problematic flight control system, and he didn't see the 90 yaw angle because he turned it off, so he raced straight down, and the control SW kept it that way.
The first one took flight over fifty years ago and we still talk about it as if they represent the promise of the future. As a culture and community, we rarely view Project Apollo in the same way. To me, in contrast to the Blackbird, our first step outside our cradle looks dated. The Saturn V is an ode to the sheer force of will required to send human beings to another heavenly body. It certainly looks the part. The Blackbirds, on the other hand, were precise, surgical instruments designed to cut borders and they look the part. Every element of the plane ends in that sharp-looking edge. There are no blunt surfaces on it. It’s one complex curve wrapped around itself and stretched into that timeless shape.
And that's before you pull back on the curtain. I don't have online sources for this, but I have read books about the project that explained how every single part within the Blackbirds - from the engines to the paint - was brought into being for this project. They set out to do something so daring and so pioneering that they had to invent new alloys to do it. And then they had to build the machines to work that alloy: new machines - tape-based robots - to precisely carve it into shape, new procedures to put it together, and new philosophies to let it fly. These planes were designed to fly so fast that ordinary Titanium-based alloys would melt or weaken over time leading to rapid, unplanned disassembly. They didn’t have more advanced ceramics which could do the job, so Kelly Johnson’s team came up with a new alloy that was annealed - or re-tempered - in flight, so that it became stronger and stronger over time. Theoretically above some classified altitude the Blackbird can go much faster than Mach 3 and keep on going until the airframe melts away at some crazy high, theoretical speed no one has bothered to check.
They did all of that in a past where the most sophisticated engineering tool in common use was a slide rule and the first scientific pocket calculator was nearly a decade into the future.
Do you ever wonder when we'll build something so daring that it will finally eclipse this project? I do. Paraphrasing Thiel, "what happened to the future? We were promised Blackbirds and got the F-35 instead."
It's kinda weird how the F-35 just looks somehow dated and like a slob compared to e.g. the older (and cooler looking) F-22. Though perhaps "cool looks" is maybe not the prime factor in fighter jet selection...
This quote opens an essay on beauty by Paul Graham, http://www.paulgraham.com/taste.html
The urban legend about why the X-32 lost out to what become the F-35 is it having a stooopid looking mouth on it: https://i.imgur.com/1GW21we.jpg
If you were to write down all the ways in which you could measure an airplane—payload, fuel, ordnance, handling—and ask 100 pilots to rank which is the most important, I guarantee you that 100 out of 100 pilots would say “situational awareness.” By far. Not a single pilot in the world would say “turn radius.” Not one. Because the more you know, the more accurately you know it, the better able you are to make a decision.
In situational awareness, the F-35 is superior to all platforms, including the Raptor. I’d never been in an airplane that so effectively and seamlessly integrates information to tell me what’s going on around me—and not just from the radio frequency spectrum, but laser, infrared, electro-optical. That’s usually the first thing people notice when they get in the airplane. They know so much more than they ever knew before.
With that said, if push came to shove, the electronics on the F-22 could be quickly replaced/augmented to either have a focused IRST ala the SU-35 or a 360 system like F-35's EODAS. Your argument is in line with "It would be difficult to restart the F-22's production line." Sure, but neither doing that or updating it would cost nearly as much as the amount of money that went into the F-35.
I think IRST wasn't made a priority because the US expects to have AWACS wherever they operate and the F-22s to shoot based on AWACS data without ever actively emitting themselves anyway. That or planes toggling radar one at a time and passing data via datalink to their squadron, which makes them fairly safe (at least that was the idea with datalinks).
EDIT: Thanks everyone, I wasn't aware that the F22 had a higher price and additional export restrictions.
One F-22 vs one F-35 is a contest obviously in favor of the F-22. One F-22 vs. three F-35s becomes a lot more ambiguous, particularly when we are not at war and there's no guarantee that any of these planes will do anything more than force projection.
(The F-35 very much seems like a peacetime fighter to me, and that may be exactly what the U.S. needs right now. History has shown that basically all your assumptions about how the next war will unfold go out the window once the next war actually starts. Under those conditions, it may make more sense to try out a bunch of new technologies, keep the defense contractors alive and the aeronautical engineers employed, contain costs, and build enough numbers that you don't get completely steamrolled in the early days of a war. Then when war actually does break out, you rapidly adjust and build the planes that you actually need, when you have real data about what's winning on the battlefield.)
Also, don't forget that nuclear weapons still exist. Nuclear powers shooting down squadrons of each others fighters to achieve "victory" does not seem likely.
Other controversial opinion: I think that the assumption that the next major war will be between nation-states is a likely candidate for one that'll go out the window. In my view, the next major war will be like Syria but on a global scale, with many semi-organized subnational groups duking it out in exceptionally nasty urban & guerilla warfare.
2. F22's are only fighter jets. F35 for better and worse is designed to do just about everything.
But to be fair, as the other comments have pointed out the F-35 is lower cost, a decent peace time machine and is has flexible configurations.
The F-22 also can't be sold as an export.
Given a volunteer military, and remembering their advertising in high school, they probably want people to feel as cool as possible joining up too.
I've always thought it was a shame the YF-23 wasn't developed into the role eventually filled by the F-35. It had a lower radar cross-section than the F-22, could supercruise faster, had better range, and with the deletion of the afterburners (not necessary for the revised role, especially when you can truck along at M1.8 without them) it could have opened up a lot of space for additional weapons storage. And it was a long way to being a developed aircraft. Could have been finished much more cheaply than the F-35, no doubt.
 Not sure of the CG shift implications, though.
 Not sure if those savings would have been eaten up by higher operating costs.
Quote I've heard attributed to WW2 pilots, but google isn't helping me with.
We can't do that kind of engineering anymore. Computers have made us ... lazy? That's not really the word. With so much computing power at hand, we just don't have the pinpoint focus that it would take to make another SR-71 and not hobble it with over engineering and feature creep. Or even just being able to let go of a nagging problem. For example, a proper sealant couldn't be found to keep the fuel from leaking so they just said whatever and let it leak fuel until it warmed up. Nobody would do that today.
Computers didn't make us lazy, but the Git-R-Done mentality of the old projects got gobbled up by the bureaucracy in all of our big defense contractors/aerospace companies. It's super hard for a Kelly Johnson type to fend off thousands of middle managers all trying to justify their position.
The F-35 is a giant weird beast because it's massively multi-mission, but really as a backstop to what we can't do with drones, missiles, and satellites.
No, it's multimission because new airframe types for manned combat aircraft that could meet evolving demands were becoming giant weird beasts and getting exponentially more expensive (something that typically happens with classes of systems as they become unviable) anyway, and doing one airframe for almost every conceivable role was envisioned as a means of containing costs.
Still, I think the point about it being a backstop to unmanned aerial assets stands. I don't know if it needs to be optimized for any single mission when it's likely to be a worse choice than one of those assets.
Didn't they learn from the Phantom that one airframe for all tasks simply doesn't work ?
Will it not be most likely the last manned fighter jet?
Maybe not more, but up there with it are the Concorde, and the H&K G11.
Also, if you like the SR-71, check out the A-12. The immediate predecessor of the SR-71, very easy to confuse the two, with the notable exception of the A-12 having a single seat. I think that makes it even cooler. Just one pilot, no other aircrew, up there alone with the machine. That's really incredible to me.
With the wingtips are folded up, the A-12 looks like something out of Star Wars.
The triangular shape is reminiscent of B-2 Spirit, though these are of course completely different beasts. Both the A-12 and B-2 were designed during roughly the same era, late 1980s. I guess there was some kind of cross-pollination of ideas (maybe via DARPA) for a triangular design to appear like this?
Don't even bother trying to figure out US military naming schemes.
I suspect that the reason the A-12 and the B-2 looked alike is that there is enough similarity in mission that the best shape ended up that way. (Or as an old friend used to say, "aerodynamics can't lie.")
Knowing the CIA, that designation may have been misdirection too. 'Main battle tanks' are called 'tanks' today because of WWI era misdirection. Instead of calling them "armoured tractors" or something descriptive like that, the British called them "water carriers." The abbreviation of that (w.c.) was considered crude though, so they were renamed "tanks" as in a container for carrying water. This was to ensure any German spy who overheard the wrong conversation would get the wrong impression.
The Lockheed A-12 has a familiar appearance... I always thought it somehow looks like a flying dragrace car. Everything in it screams "fast".
And as for the "wrong" (McDonnell-Douglas) A-12, another thing I found interesting was that some of the modern drone designs also have the same triangular shape. (Like X47-B, X45-C/Phantom Ray, nEUROn, RQ-170)
And the X47-B can even fold its wings!
I'm very skeptical of these rumors. The SR-71 inlets were shaped for a specific range of mach numbers, and wouldn't work beyond that. Significant new engineering would be needed to go well beyond mach 3.5.
In an SR-71?
However, the economics of never really made sense in regards to its utility. Only during the cold war could such a project be dragged into the realm of possibility.
That's a rather understated way of saying "She'll fly herself apart!"
I should be working, but your comment was enthralling.
Some of my favorite stories include the fact that you could take off in the morning, fly up to the arctic circle, and back down in time for dinner in the evening.
Maybe we have, and just haven't been told about it.
It certainly looks cool though.
The parent comment simply talks about engineering challenges and it’s frankly amazing.
There was a story where Trump basically tried to get NASA to try and do a manned mars mission within 10 years. He said he’d offer them an unlimited budget. They said no.
Now, feasibility of any of this aside: that just depresses me more than anything I’d heard in a long while. You won’t even try? C’mon! What happened to “we are doing it not because it’s easy, but because it’s hard”? The mentality that we can do literally anything we put our minds to?
Look at the way that people want to vilify Elon Musk. Here’s a guy that embodies everything I grew believing was the American spirit, and apparently that makes him a bad guy. So sad.
"Cancel all your research projects and focus on a rushed, unsafe, mission to Mars within the next four years" isn't an offer I'd take either.
And that's even supposing he has the political power to actually give them the money he was offering. Which he doesn't.
There's a Tyson show on it, perhaps still on Netflix if interested.
They are going to try. Just a month before, Trump himself had signed a bill outlining a manned Mars mission, and the timeline to actually do it.
What they said no to was a spur of the moment request, made without discussing feasibility (or anything else about it) with anyone else before making it, to do it way way way faster than that.
Here's an article with the details .
NASA is an enormous entity with many different branches, and each aerospace mission must be planned and funded carefully. Upper management at NASA must also consider the politics of a situation; what would happen to NASA if they agreed to such an offer and failed to deliver results?
This seems like it was a political move by Trump that allowed him to look good by making a risky request. If NASA says "yes" and gets to Mars, Trump wins. If NASA says "yes" and fails to get to Mars, Trump says "I gave the money and you didn't do your part". If NASA says "no", Trump says "I offered them the money but they didn't take it".
 - https://www.theatlantic.com/science/archive/2019/01/trump-ma...
UPDATE: Video with better sound thanks to https://news.ycombinator.com/item?id=19505767 I found the specific story I was referring to at 33m
Here's one with better sound: https://www.youtube.com/watch?v=BZRP1q1PGUk
I was surprised to find the plane can be flown solo , and with no pressure suit below 50,000 feet .
There is also a section on "Tactical Limits" describing scenarios where exceeding normal operating limits is advised to exit a hostile area 
Doubtlessly a consequence of the A-12 being flown solo. The SR-71 was a derivative of the A-12.
I first came across the story here on HN, and every time someone mentions it I re-read it. It truly never gets old; only now I just got goosebumps. I think it's the people bonding part that gets me.
The enemy will fire missiles at us. What shall we do? (1) Invent missile-proof armor, (2) Build computer-guided anti-missile lasers, (3) Just fly really fast.
I guess all of those are hard to do. Making the SR-71 fly at Mach 3 wasn't easy. But to me it seems more elegant.
In the early 2000s, Google made a big deal about speed in web apps. I think it still does, but I don't hear about it anymore. And everybody knows that GMail is slower. But I appreciated it while it lasted.
On the ground to leaked fuel like a sieve, it was only once it reached operational speed that the joints & frame heated up and sealed it, (thus requiring a refueling shortly after take-off).
These sorts of stories are what impress me about programs like this. No commercial product could ever be so expensive, so difficult, so wildly impractical. The military are practically the only ones who can do things like this, because the need is so great it justifies all the craziness. I work at NASA and we do crazy things like sending robots to Mars, but that seems tame compared to the insanity of something like the SR-71.
“Had the spy plane violated Soviet airspace, a live missile launch would have been carried out. There was no practically chance the aircraft could avoid an R-33 missile.”
I do suspect the "surround from all directions" approach detailed later would've worked, but that's why we moved off to stealth and satellites.
https://www.youtube.com/watch?v=-5nSKLyrM1s (long talk by SR-71 pilot Maury Rosenberg mentioned in the first video)
https://www.youtube.com/watch?v=CeBu6mRDaro (an even longer talk by another SR-71 pilot Richard Graham)
so we don't really know if they have the capability, but after they downed the U2 in 1960, seems the US didn't want to find out empirically.
that said, you have to love this plane. it's a spaceship.
The Chinese sent up a fighter after it, and, well, it wasn't fast enough. It also had too low of a ceiling.
Can't cite a source (I read about this, what, four decades ago?) so I can't prove it happened.
You want fast, take a look at the Sprint missiles. The damn things had 100g of acceleration and could hit 3400 m/s.
Even the slightest turn at those speeds moves the airplane by 10s of miles.
Any attempt to intercept or shoot down planes that fast happens at great distances and is totally dependent on computers, radar, and missiles.
> It wouldn't get much time to spy at that speed
That's why you take photos and do the spying part back on base. The SR-71's weapon was its sophisticated camera setup.
> it's fuel limits won't allow great distances without speed changes
When it set its speed record, it crossed from LA to DC on one tank of fuel. (It tanked up immediately after takeoff and immediately before landing, but the cross-country flying part didn't involve a tanker.)
There are many faster objects, including the X-15 and Shuttle. Both are faster than the Blackbird but do not count. Shuttle is a spacecraft but even during reentry, shuttle could not hit such speeds unaided by other aircraft that departed from it along the way (the boosters etx). Nor could the X-15 which was dropped from a larger carrier aircraft. Both could not get to their records speed unaided.
Neither could the SR-71/YF-12. They burnt so much fuel getting off the ground that, to preform a run to top speed and get home, they needed to refuel. So how is that fundamentally different than Shuttle or the X-15? For an aircraft to qualify as an aircraft it should be able to get up and down without help. Therefore it is the Mig-25/31 that deserves the praise of "fastest aircraft".
They could have taken off and accelerated to record-breaking speeds if that's all they wanted to do, but the typical mission profile was to fly to far away locations to conduct surveillance, so in-air refueling was always part of the mission profile.
TLDR: They needed full tanks (more or less) or an inert layer of nitrogen over the gas in the tanks before hitting Mach 3 or else the fumes in the tank might ignite. At the end you'll see that they had a system for fueling the tanks on the ground in order to hit mach 3 right after takeoff but it was a maintenance nightmare.
If I remember right, the SR71 could fly at Mach 3 for up to 90 minutes between refuelings. That's significantly longer than any jet ever made.
Except the XB-70. Data is rare, but it was to cruise at 3.0 for somewhere between one and two hours.