US Air Force Hypersonic Test Fails

[Ryan_m_b]

Seems a real shame, apparently a control fin was faulty.
http://www.bbc.co.uk/news/technology-19277620

The US Air Force has said an attempt to fly its hypersonic jet Waverider at Mach 6 (3,600mph; 5795km/h) failed.

 

[boneh3ad]

Luckily they have one more vehicle and the previous test was a success so they have justification to use said remaining vehicle.

 

[Ryan_m_b]

Luckily they have one more vehicle and the previous test was a success so they have justification to use said remaining vehicle.

Actually I think the first test was successful, the second failed and this is the third. Otherwise you're right, at least they have something to back up that it can work (that and the fact that the reason this failed was an unfortunate subsystem error).

 

[boneh3ad]

You are correct. The second test had an engine unstart when switching to JP7 fuel.

 

[Greg Bernhardt]

Anyone know when the next test is scheduled for?

 

[boneh3ad]

Hasn't been decided if there is one yet.

 

[LURCH]

Another X-51 Test Failure

The X-51 had another failed test flight around mid-August. IIRC; the first test flight failed because the rocket carrying the test vehicle malfunctioned. Then I think they had one good test that ran for about two min. Then one where the engine itself failed to perform as expected (flamed out in just a few seconds). And now this.

So only two flights have been flown that actually tested the engine itself; one failure and one that is gaurdedly being called a success. Does anybody know how much it's costing to make each attempt? Considering how much time and effort is being wasted (on flights that yield no usefull data) and what are the potential benifits, do you guys think the project will be discontinued?

 

[RandomGuy88]

What I think is sad is that poor NASA has a minuscule budget compared to the military and keeps getting their budget cut, but they pull of the Curiosity landing without a problem. Maybe the engineers at NASA should take over for the air force.

 

[boneh3ad]

I fully support the substantial increase of NASA's budget, but suggesting that the X-51 program has any bearing in this is disingenuous. The X-51, despite several failures, has been a success. Even the engine flameout produced valuable data and the program for the first time ever achieved air-breathing, self-sustained hypersonic flight. prior vehicles such as the X-43 started their scramjets but didn't actually accelerate beyond the speed attained by the rocket booster.

At any rate, I believe there is only one more X-51 vehicle made and it hasn't been decided whether to use it yet. I would certainly hope they do. I can pretty much guarantee you that scramjet testing will not end with the X-51 though.

 

[Vadar2012]

Australia is about to launch a newly built scramjet, which has been developed over the past few years at the University of Queenland. It's first test flight is scheduled for march 2013. If you're interested type "Scramspace" into google. I've had a little part in it and I know they hope to beat the waverider. Let's hope someone gets it right.

 

[Aero51]

If scramjets are made practical they will usher in a new age of flight! For the sake of the aerospace industry they better not stop the research!

 

[boneh3ad]

It would be a long time before any vehicle was produced with a scramjet for carrying people. Unfortunately, the first application, as is common, will be military, i.e. hypersonic cruise missiles. Eventually they may find their way into SSTO vehicles and after that maybe commercial vehicles.

 

[LURCH]

Started another thread before I sawthis one. What I'm wondering is how much each test flight costs. Has anyone heard any figures? I mean, the flameout was one thing; at least we learned something about scramjet tech from that. But this failure taught us virtually nothing, and it cost just as much as a successfull flight. I am a bit concerned that a string of failed tests could sideline the whole program, whether or ont the failures have anything to do with the scramjet itself.

But as BoneH3ad pointed out:

I can pretty much guarantee you that scramjet testing will not end with the X-51 though.

After all, it is a technology with potential military applications.

 

[berkeman]

Started another thread before I sawthis one.

(Two threads merged)

 

[Ryan_m_b]

After all, it is a technology with potential military applications.

Just to play devil's advocate here are the applications really that great or are they niché? The SR-71 Blackbird was the peak in a trend for ever faster jets but was superceded by satellites, missiles and a general change in the manner in which jets were used. Are there many situations we can envision in which hypersonic aircraft would be militarily advantageous over other technology/tactics?

 

[Pkruse]

They are developing completely new engine technology that will not only be very fast, but also fuel efficient and quiet enough to fly out of civilian airports. They are also learning how to quiet the sonic boom. This thing is pushing current technology on all fronts.

 

[Aero51]

Ryan_m_b, consider this application: The ability to reach any location in the world in about 2 hours! If our entire airforce had this capability aircraft carriers would be rendered useless for most fighterjet applications. Consider also the new types of aerodynamic research that will be conducted in the hypersonic regime. We may have entirely new space vehicle shapes in the next 50 years. Hypersonic combustion also has applicability to the scram cannon - a device which could theoretically launch sattities into orbit at a fraction of the cost today.

 

[boneh3ad]

Started another thread before I sawthis one. What I'm wondering is how much each test flight costs. Has anyone heard any figures? I mean, the flameout was one thing; at least we learned something about scramjet tech from that. But this failure taught us virtually nothing, and it cost just as much as a successfull flight. I am a bit concerned that a string of failed tests could sideline the whole program, whether or ont the failures have anything to do with the scramjet itself.

It isn't really a per-flight kind of thing. They built a finite number of testbed vehicles. So far I think the program has cost on the order of $140 according to GlobalSecurity.org. That is absolutely nothing in the grand scheme of government spending.

Just to play devil's advocate here are the applications really that great or are they niché? The SR-71 Blackbird was the peak in a trend for ever faster jets but was superceded by satellites, missiles and a general change in the manner in which jets were used. Are there many situations we can envision in which hypersonic aircraft would be militarily advantageous over other technology/tactics?

The SR-71 is a totally different animal. It was built for surveillance and was therefore superseded by satellites. The development of scramjets, on the other hand, has been driven more for a combination of payload delivery to target in the form of cruise missiles and by the goal of single-stage-to-orbit spaceflight.

Space cannot be weaponized without violating various agreements and setting off an arms race, so nothing like that can replace the idea of a hypersonic cruise missile for rapid-response. Ballistic missiles armed with conventional warheads would also be a bad idea, as evidenced by the fact that we briefly looked into it and ran into a cacophony of protest from other nations because of the potential for confusion with actual nuclear launches. In other words, the military reason for developing scramjets will not go away any time soon.

On the other hand, reusable SSTO vehicles are something that have been highly sought after for years but have been elusive, and using scramjets is one of the more promising ways to do it. The interest in this will ebb and flow with the economy and budgets, but the idea will hang around until it is someday achieved.

Militarily, consider this: a Mach 6 cruise missile could be fired from Los Angeles and hit Beijing within about 90 minutes (Islamabad in about 2 hours) assuming that Mach 6 was at, say, 40,000 feet. Unlike an ICBM, a cruise missile launch would not be easily detectable from space because it wouldn't have that huge heat signature. It would be detected fairly late in its journey so the target would have much less time to react than that full flight time. I would imagine it would be on the same order as the 30 minutes reaction time available to an ICBM launch, only without triggering an exchange of ICBM fire. On top of that, there are no current SAM systems available to hit a target moving at those speeds. I am sure they could try and retool a Patriot to do the job, but hitting an air-breathing, maneuverable vehicle like a cruise missile moving at those speeds is significantly harder than a re-entry vehicle on a ballistic trajectory. In essence, such a weapon gives the military fielding it the ability to strike anywhere in the world with about 2 hours notice assuming they could put enough fuel on board without being anywhere near as provocative as launching an ICBM.

If our entire airforce had this capability aircraft carriers would be rendered useless for most fighterjet applications.

Let's not go overboard, mate! The ability to project power from a close-in platform like an aircraft carrier would take a lot longer than that to replace. Hypersonic flight has its limitations, as does over-reliance on cruise missiles.

 

[LURCH]

IIRC; the first test flight failed because the rocket carrying the test vehicle malfunctioned.

OK; here i was thinking of the X-43, the forerunner of the X-51. My bad.

(Two threads merged)

Thanks.

 

[HowlerMonkey]

My buddy was one of the engine designers at Pratt/Whitney and said that the plane that failed was the one with the "sweet engine" while the remaining engine/airframe is slightly different and not as "sweet" as he would like.

He won't expound any further than that.

 

[Vadar2012]

My buddy was one of the engine designers at Pratt/Whitney and said that the plane that failed was the one with the "sweet engine" while the remaining engine/airframe is slightly different and not as "sweet" as he would like.

He won't expound any further than that.

If he expanded further he'd probably be fired and sued. He probably has a level 3 clearance and has signed more confidentiallity agreements than he can count.

 

[Compressible]

So only two flights have been flown that actually tested the engine itself; one failure and one that is gaurdedly being called a success. Does anybody know how much it's costing to make each attempt? Considering how much time and effort is being wasted (on flights that yield no usefull data) and what are the potential benifits, do you guys think the project will be discontinued?

I wouldn't really call it a waste. Any in-flight data acquired is useful data for the hypersonic regime. It is exceedingly difficult (and in some cases not currently possible) to simulate the flight conditions of a hypersonic vehicle in ground-based facilities. Getting flight data like this is a tremendous advantage (though slightly costly and inefficient). Too bad they can't leave their data open to the public. I understand the reasons why, but information like this would help out the scientific community tremendously.

Are there many situations we can envision in which hypersonic aircraft would be militarily advantageous over other technology/tactics?

There are a myriad of advantages to hypersonic aircraft. As everyone else has mentioned, military benefits of being able to reach a target anywhere in the world within a few hours is a huge advantage. But you can also get a lot of in-flight aerodynamic data that wouldn't be available otherwise that can be used in space vehicle re-entry and other flight regimes that require hypersonic aerodynamic control and maneuverability.

On top of that, there are no current SAM systems available to hit a target moving at those speeds. I am sure they could try and retool a Patriot to do the job, but hitting an air-breathing, maneuverable vehicle like a cruise missile moving at those speeds is significantly harder than a re-entry vehicle on a ballistic trajectory. In essence, such a weapon gives the military fielding it the ability to strike anywhere in the world with about 2 hours notice assuming they could put enough fuel on board without being anywhere near as provocative as launching an ICBM.

There is an active area of research in direct-energy weapons that can accurately target and strike vehicles moving at hypersonic velocities. I believe Boeing and some other companies are currently working on it.

 

[boneh3ad]

Too bad they can't leave their data open to the public. I understand the reasons why, but information like this would help out the scientific community tremendously.

Surprisingly, some of it is. Just about every conference I go to has data from various hypersonic tests like the HiFIRE program. The X-planes are generally not as open though.

There is an active area of research in direct-energy weapons that can accurately target and strike vehicles moving at hypersonic velocities. I believe Boeing and some other companies are currently working on it.

The funding for the airborne laser (ABL) was cut, though, on account of the short range of such a device. The lasers dissipate too quickly in the atmosphere, not to mention the difficulties that result from diffraction and refraction over long distances. The ABL died mostly on account of the fact that to shoot down a tactical ballistic missile launched from North Korea with it, you would actually have to fly into North Korean airspace. It was never even intended to destroy anything as fast as an ICBM. It is a cool system though.

It's smaller cousin, the advanced tactical laser, is still alive though, but it is designed as an airborne weapon for use against ground targets for low collateral damage. I wouldn't be surprised to see the system retooled into a system similar to the Phalanx CIWS/C-RAM systems. That may be capable of shooting down a hypersonic cruise missile.

 

[Compressible]

The ABL died mostly on account of the fact that to shoot down a tactical ballistic missile launched from North Korea with it, you would actually have to fly into North Korean airspace.

I'd imagine that this issue could be remedied via the use of satellites granted that the proper wavelength is used to properly penetrate Earth's lower atmosphere and that you could properly house the energy generator within the satellite.

 

[boneh3ad]

I'd imagine that this issue could be remedied via the use of satellites granted that the proper wavelength is used to properly penetrate Earth's lower atmosphere and that you could properly house the energy generator within the satellite.

Probably. Unfortunately, most nations tend to object pretty vehemently to militarizing space. I can't say I blame them.

 

[Compressible]

Probably. Unfortunately, most nations tend to object pretty vehemently to militarizing space. I can't say I blame them.

I'd make the conjecture that although most countries are against militarizing space, it does not necessarily mean that some of them aren't doing it anyways. I'd say that it's highly probable that they have already started to do so. Case in point being that having satellites spy on other countries is extremely frowned upon, yet the United States and Russia have been known to do so in the past.

 

[boneh3ad]

I'd make the conjecture that although most countries are against militarizing space, it does not necessarily mean that some of them aren't doing it anyways. I'd say that it's highly probable that they have already started to do so. Case in point being that having satellites spy on other countries is extremely frowned upon, yet the United States and Russia have been known to do so in the past.

In the past? They do so constantly. That isn't nearly as frowned upon as putting actual weapons up there a la the Star Wars program under Reagan or the various proposals by various countries to have space-based nukes. In fact, your earlier proposal is very, very similar to Star Wars (the missile defense system, not the movies).

 

[LURCH]

I wouldn't really call it a waste. Any in-flight data acquired is useful data for the hypersonic regime.

So, do you think they actually get usefull data about hypersonic flight from a test in which the vehicle never gets launched? What kind of info could that yield? I can see the usefullness of the two tests I mentioned; one where the engine burned more or less as planned, and the other where it flamed out almost immediately. These are both usefull datasets. But what can they learn from the test where the booster rocket goes out of control as soon as it leaves the mothership, and has to be self-destructed with the test vehicle still attached. I mean, the vehicle tiself never even launched; I find it hard to believe any usefull data about hypersonic flight came from that. Or from this latest test, either.

Has anyone heard of any usefull information gained from these tests?

 

[Aero51]

Yes, a big topic in the hypersonic regime is stability and control. Even if the vehicle spirals out of control you can still estimate some stability derivatives.

 

[boneh3ad]

Except it spiraled out of control as a result of a defective fin. That isn't particularly useful, especially because the particular control problem is already solved considering it worked several times before.

 

[HowlerMonkey]

On top of that, there are no current SAM systems available to hit a target moving at those speeds. I am sure they could try and retool a Patriot to do the job, but hitting an air-breathing, maneuverable vehicle like a cruise missile moving at those speeds is significantly harder than a re-entry vehicle on a ballistic trajectory. In essence, such a weapon gives the military fielding it the ability to strike anywhere in the world with about 2 hours notice assuming they could put enough fuel on board without being anywhere near as provocative as launching an ICBM.

Check the sprint missile and it's descendents.

The altitude at which a scramjet currently needs to operate makes it trackable.

https://www.youtube.com/watch?v=YZZV464z9g8

 

[Aero51]

Except it spiraled out of control as a result of a defective fin. That isn't particularly useful, especially because the particular control problem is already solved considering it worked several times before.

At least the engineers now know how the X-43 will perform under broken fin conditions. Maybe they will find that all X-43's should be designed with broken fins to save on cost...you never know.

On a serious note, it still seems useful to at least know what will happen if something goes wrong.