DARPA/Boeing X-51A WaveRider

I will happily* eat words if it reached Mach 6 and/or maintained Mach 5.5 for the majority of the flight, and made it to the planned end of the flight. Remember the first flight was all good news and then in the fine print we discover that it didn't accelerate any faster than what the booster dropped it off at.


*Been taking the George Costanza approach and betting on the opposite of what I want to happen. ;D
 
seruriermarshal said:
First speed is Mach 4.88 , May 2010 .
Click to expand...

Anything less than breaking ASALMs record (Mach 5.4) of 30+ years ago would be a disappointment in my book.

"Coming in the wake of these disappointing prior tests, the success of the May 1 flight could therefore be pivotal in helping drive further research and development to meet the Air Force’s long-term goal of hypersonic capability. The test involved the last of the four vehicles to be built by Boeing and configured with a Pratt & Whitney Rocketdyne SJX61 dual-mode ramjet/scramjet engine, and incorporated improvements and lessons learned from the three former flights."

Okay, wait a second. I thought HyFly had the dual-mode engine and X-51 had scramjet only? ??? I REALLY hope they didn't just dial back the mission so it would make it to the end it's flight for appearances sake. Theoretically we could be looking at nothing but a conventional ramjet flight at Mach 5.01 that did nothing ASALM didn't do better 30 years ago. I am interested in the details.
 
sferrin said:
seruriermarshal said:
First speed is Mach 4.88 , May 2010 .
Click to expand...

Anything less than breaking ASALMs record (Mach 5.4) of 30+ years ago would be a disappointment in my book.

"Coming in the wake of these disappointing prior tests, the success of the May 1 flight could therefore be pivotal in helping drive further research and development to meet the Air Force’s long-term goal of hypersonic capability. The test involved the last of the four vehicles to be built by Boeing and configured with a Pratt & Whitney Rocketdyne SJX61 dual-mode ramjet/scramjet engine, and incorporated improvements and lessons learned from the three former flights."

Okay, wait a second. I thought HyFly had the dual-mode engine and X-51 had scramjet only? ??? I REALLY hope they didn't just dial back the mission so it would make it to the end it's flight for appearances sake. Theoretically we could be looking at nothing but a conventional ramjet flight at Mach 5.01 that did nothing ASALM didn't do better 30 years ago. I am interested in the details.
Click to expand...

I'm with sferrin just build ASALM and done hypersonic strike missile.
 
Judging from the record of SLAT (son of ASALM), I wouldn't be too quick to jump on that bandwagon...
 
sferrin said:
seruriermarshal said:
First speed is Mach 4.88 , May 2010 .
Click to expand...

Anything less than breaking ASALMs record (Mach 5.4) of 30+ years ago would be a disappointment in my book.

"Coming in the wake of these disappointing prior tests, the success of the May 1 flight could therefore be pivotal in helping drive further research and development to meet the Air Force’s long-term goal of hypersonic capability. The test involved the last of the four vehicles to be built by Boeing and configured with a Pratt & Whitney Rocketdyne SJX61 dual-mode ramjet/scramjet engine, and incorporated improvements and lessons learned from the three former flights."

Okay, wait a second. I thought HyFly had the dual-mode engine and X-51 had scramjet only? ??? I REALLY hope they didn't just dial back the mission so it would make it to the end it's flight for appearances sake. Theoretically we could be looking at nothing but a conventional ramjet flight at Mach 5.01 that did nothing ASALM didn't do better 30 years ago. I am interested in the details.
Click to expand...


HyFly used the JHU/APL DCR (dual combustor ramjet). Subsonic inlets fed a subsonic fuel-rich gas generator whose choked exhaust fed into a supersonic combustor where it mixed with additional air from supersonic inlets and burned. It used no fuel-cooled components and the GG provided the hot partially cracked fuel to the supersonic combustor.

A dual mode ramjet scramjet aka thermally throated ramjet has no physical minimum downstream of the throat and can operate in ramjet mode with a thermal throat in a divergent combustor or of pure scramjet mode. Here much of this engine is fuel-cooled and this heated, partially cracked fuel is then injected into the combustor.
 
Steve Pace said:
sferrin said:
Steve Pace said:
-SP
Click to expand...

Relevance?
Click to expand...
None except Mn7 speed. -SP
Click to expand...

Yeah, but that's the X-43. Not the X-51. Different vehicles altogether so it's not really relevant here. May as well have thrown up a picture of a Minuteman missile.
 
aim9xray said:
Judging from the record of SLAT (son of ASALM), I wouldn't be too quick to jump on that bandwagon...
Click to expand...

The "LA" in "SLAT" was for "low altitude" (i.e. a different part of the envelope than the missile was designed for). And at least ASALM had some successful flights which already puts it ahead of anything being tested today.
 
USAF press release

130501-F-QG253-009.jpg


5/3/2013 - WRIGHT-PATTERSON AIR FORCE BASE, Ohio -- The final flight of the X-51A Waverider test program has accomplished a breakthrough in the development of flight reaching Mach 5.1 over the Pacific Ocean on May 1 a little after 10 a.m. Pacific Time.

"It was a full mission success," said Charlie Brink, X-51A program manager for the Air Force Research Laboratory Aerospace Systems Directorate.

The cruiser traveled over 230 nautical miles in just over six minutes over the Point Mugu Naval Air Warfare Center Sea Range. It was the longest of the four X-51A test flights and the longest air-breathing hypersonic flight ever.

The X-51A took off from the Air Force Test Center at Edwards AFB, Calif., under the wing of a B-52H Stratofortress. It was released at approximately 50,000 feet and accelerated to Mach 4.8 in about 26 seconds powered by a solid rocket booster. After separating from the booster, the cruiser's scramjet engine then lit and accelerated to Mach 5.1 at 60,000 feet.

After exhausting its 240-second fuel supply, the vehicle continued to send back telemetry data until it splashed down into the ocean and was destroyed as designed. All told, 370 seconds of data was collected from the experiment.
 
Mach 5.1. :-\ So, not even what a plain old ramjet did 30 years ago. I am (unsurprisingly) disappointed.

From the first post in the thread:

"During the flight test, currently planned Dec. 2, the Air Force Flight Test Center's B-52 will carry the X-51A to 50,000 feet over the Pacific Ocean then release it. A solid rocket booster from an Army tactical missile system then will ignite and accelerate the X-51 to about Mach 4.5. Then, the supersonic combustion ramjet propulsion system will propel the vehicle for five minutes to more than Mach 6. Hypersonic combustion generates intense heat so routing of the engine's own JP-7 fuel will help keep the engine at the desired operating temperature."

My guess is they dialed the test all the way back to, "whatever we can do so it makes it to the end of the flight". The alternative is that it doesn't have the capability to go any faster.
 
sferrin said:
Mach 5.1. :-\ So, not even what a plain old ramjet did 30 years ago. I am (unsurprisingly) disappointed.

From the first post in the thread:

"During the flight test, currently planned Dec. 2, the Air Force Flight Test Center's B-52 will carry the X-51A to 50,000 feet over the Pacific Ocean then release it. A solid rocket booster from an Army tactical missile system then will ignite and accelerate the X-51 to about Mach 4.5. Then, the supersonic combustion ramjet propulsion system will propel the vehicle for five minutes to more than Mach 6. Hypersonic combustion generates intense heat so routing of the engine's own JP-7 fuel will help keep the engine at the desired operating temperature."

My guess is they dialed the test all the way back to, "whatever we can do so it makes it to the end of the flight". The alternative is that it doesn't have the capability to go any faster.
Click to expand...

My question would be that despite the slower speed does this confirm the flowfield/path ignition and sustained burn technology of this design and can this then be ramped up in the future?
 
bobbymike said:
sferrin said:
Mach 5.1. :-\ So, not even what a plain old ramjet did 30 years ago. I am (unsurprisingly) disappointed.

From the first post in the thread:

"During the flight test, currently planned Dec. 2, the Air Force Flight Test Center's B-52 will carry the X-51A to 50,000 feet over the Pacific Ocean then release it. A solid rocket booster from an Army tactical missile system then will ignite and accelerate the X-51 to about Mach 4.5. Then, the supersonic combustion ramjet propulsion system will propel the vehicle for five minutes to more than Mach 6. Hypersonic combustion generates intense heat so routing of the engine's own JP-7 fuel will help keep the engine at the desired operating temperature."

My guess is they dialed the test all the way back to, "whatever we can do so it makes it to the end of the flight". The alternative is that it doesn't have the capability to go any faster.
Click to expand...

My question would be that despite the slower speed does this confirm the flowfield/path ignition and sustained burn technology of this design and can this then be ramped up in the future?
Click to expand...

I'm guessing what they did is dial it back enough that it shows acceleration (if only barely) but that it didn't stress it as much to increase the odds of making it to the end of the flight. If this one had tanked too, you can be sure the program would have received a huge "CANCEL!!". Now? Maybe it'll have a chance to move forward. It's mainly the geek in me that was hoping for Mach 6+. ;D
 
sferrin: reference about that ASALM Mach 5.6+ flight 30+ years ago ??
TIA
 
bobbymike said:
sferrin said:
Mach 5.1. :-\ So, not even what a plain old ramjet did 30 years ago. I am (unsurprisingly) disappointed.

From the first post in the thread:

"During the flight test, currently planned Dec. 2, the Air Force Flight Test Center's B-52 will carry the X-51A to 50,000 feet over the Pacific Ocean then release it. A solid rocket booster from an Army tactical missile system then will ignite and accelerate the X-51 to about Mach 4.5. Then, the supersonic combustion ramjet propulsion system will propel the vehicle for five minutes to more than Mach 6. Hypersonic combustion generates intense heat so routing of the engine's own JP-7 fuel will help keep the engine at the desired operating temperature."

My guess is they dialed the test all the way back to, "whatever we can do so it makes it to the end of the flight". The alternative is that it doesn't have the capability to go any faster.
Click to expand...

My question would be that despite the slower speed does this confirm the flowfield/path ignition and sustained burn technology of this design and can this then be ramped up in the future?
Click to expand...

Yes!

Or put another way.
That ramjet is near its speed limit without adding stuff to it.

But a endothermic fueled, fuel cooled structure, dual mode scramjet flying SLOW and ACCELERATING
(therefore positive thrust) to Mach 5.1!!
HOLY TOLEDO!!!!
I'm pretty darned pleased actually.

But I don't know all the inside information.
But if one tries to assimilate all the public scramjet tech stuff like I do,
this is actually pretty cool! And if you guys are right about them dialing
it back and still doing this! That is VERY cool!!

Offer me an ASALM or an X-51 as the foundation for the future, I'd take the
X-51 hands down!

Good job guys!
 
shockonlip said:
bobbymike said:
sferrin said:
Mach 5.1. :-\ So, not even what a plain old ramjet did 30 years ago. I am (unsurprisingly) disappointed.

From the first post in the thread:

"During the flight test, currently planned Dec. 2, the Air Force Flight Test Center's B-52 will carry the X-51A to 50,000 feet over the Pacific Ocean then release it. A solid rocket booster from an Army tactical missile system then will ignite and accelerate the X-51 to about Mach 4.5. Then, the supersonic combustion ramjet propulsion system will propel the vehicle for five minutes to more than Mach 6. Hypersonic combustion generates intense heat so routing of the engine's own JP-7 fuel will help keep the engine at the desired operating temperature."

My guess is they dialed the test all the way back to, "whatever we can do so it makes it to the end of the flight". The alternative is that it doesn't have the capability to go any faster.
Click to expand...

My question would be that despite the slower speed does this confirm the flowfield/path ignition and sustained burn technology of this design and can this then be ramped up in the future?
Click to expand...

Yes!

Or put another way.
That ramjet is near its speed limit without adding stuff to it.

But a endothermic fueled, fuel cooled structure, dual mode scramjet flying SLOW and ACCELERATING
(therefore positive thrust) to Mach 5.1!!
HOLY TOLEDO!!!!
I'm pretty darned pleased actually.

But I don't know all the inside information.
But if one tries to assimilate all the public scramjet tech stuff like I do,
this is actually pretty cool! And if you guys are right about them dialing
it back and still doing this! That is VERY cool!!

Offer me an ASALM or an X-51 as the foundation for the future, I'd take the
X-51 hands down!

Good job guys!
Click to expand...
I think X-51 in it's current form is nowhere near being useful for a weapon. Way too big for what you get. Look how compact ASALM was by comparison. Even HyFly was much smaller. It's too bad they couldn't get HyFly to work because I think that one had some real potential at being fast-tracked to a weapon. But they didn't even dare try LRASM-B. . .too risky.
 
Great news ! Now they can put it in FaCET and other program ! that's meaning scramjet UAV , Aircraft

:)
 
seruriermarshal said:
Great news ! Now they can put it in FaCET and other program ! that's meaning scramjet UAV , Aircraft

:)
Click to expand...

AFAIK that thing is deader than T-rex.
 
UAV means Unoccupied Aerial Vehicle - Men and Women fly them. - SP
 
sferrin said:
bipa said:
sferrin: reference about that ASALM Mach 5.6+ flight 30+ years ago ??
Click to expand...

It was on one of the USAF research labs sites history section. About 10 years ago. It was a one-paragraph blurb.
http://www.designation-systems.net/dusrm/app4/asalm.html
http://www.secretprojects.co.uk/forum/index.php/topic,466.0.html

If you felt ambitious you could probably dig through the AIAA and Flight International archives to find more information.
Click to expand...

Thanks.
I already knew those references, but I have always been skeptical about this story of a vehicle "accidentally" reaching M=5.5 while its design was for M=4 to 4.5, so I was wondering whether you had other references.
Unfortunately I can't find a good picture of the MM PTV vehicle, but Flateric has posted some good drawings and (though I know it is hard to tell from the naked eye) the inlet design does not at all look like it could allow positive thrust beyond M>5. If otherwise, I agree with you that it is a shame the US have not invested more into further developing this vehicle (and inlet concept).

Could it be that it was the rocket that went out of control (impulse too big?) and eventually dropped the ramjet above M=5 ? Also kind of hard to believe, but...

On the thermal aspects... On my calculator, total temperature @ M=5.4 and 12,000 m should be about 1100-1200°C (2000-2200°F).
It may leave you with a wall temperature around 1000-1100°C (1800-2000°F).
While at M=4.5 (same altitude), the total temperature should be around 800°C (1400-1500°F) and wall temperature around 700°C (1300°F).

(any hypersonics expert please feel free to rectify my rough estimates)

So from a materials standpoint, that looks like a completely different story between M=4.5 and M=5.4. Like titanium skins, high temperature edges (maybe CMC)... In any case, it seems unlikely that this M=5.4 ride lasted for more than a few seconds.
 
bipa said:
sferrin said:
bipa said:
sferrin: reference about that ASALM Mach 5.6+ flight 30+ years ago ??
Click to expand...

It was on one of the USAF research labs sites history section. About 10 years ago. It was a one-paragraph blurb.
http://www.designation-systems.net/dusrm/app4/asalm.html
http://www.secretprojects.co.uk/forum/index.php/topic,466.0.html

If you felt ambitious you could probably dig through the AIAA and Flight International archives to find more information.
Click to expand...

Thanks.
I already knew those references, but I have always been skeptical about this story of a vehicle "accidentally" reaching M=5.5 while its design was for M=4 to 4.5, so I was wondering whether you had other references.
Unfortunately I can't find a good picture of the MM PTV vehicle, but Flateric has posted some good drawings and (though I know it is hard to tell from the naked eye) the inlet design does not at all look like it could allow positive thrust beyond M>5. If otherwise, I agree with you that it is a shame the US have not invested more into further developing this vehicle (and inlet concept).

Could it be that it was the rocket that went out of control (impulse too big?) and eventually dropped the ramjet above M=5 ? Also kind of hard to believe, but...

On the thermal aspects... On my calculator, total temperature @ M=5.4 and 12,000 m should be about 1100-1200°C (2000-2200°F).
It may leave you with a wall temperature around 1000-1100°C (1800-2000°F).
While at M=4.5 (same altitude), the total temperature should be around 800°C (1400-1500°F) and wall temperature around 700°C (1300°F).

(any hypersonics expert please feel free to rectify my rough estimates)

So from a materials standpoint, that looks like a completely different story between M=4.5 and M=5.4. Like titanium skins, high temperature edges (maybe CMC)... In any case, it seems unlikely that this M=5.4 ride lasted for more than a few seconds.
Click to expand...

Look at the rocket section and then compare it to what it took to get the X-51 to Mach 4.8. There's no way the integral booster of ASALM had enough impulse to get it to mach 5+. Given that it was a ramjet and not a scramjet it likely only had enough impulse to get it to a high enough speed for the ramjet to take over. And according to the AFRL site the reason it oversped out of control is that there was a malfunction with the fuel control system. It did keep going until it ran out of fuel though.
 
sferrin said:
bipa said:
sferrin said:
bipa said:
sferrin: reference about that ASALM Mach 5.6+ flight 30+ years ago ??
Click to expand...
It was on one of the USAF research labs sites history section. About 10 years ago. It was a one-paragraph blurb.
http://www.designation-systems.net/dusrm/app4/asalm.html
http://www.secretprojects.co.uk/forum/index.php/topic,466.0.html
Click to expand...
Could it be that it was the rocket that went out of control (impulse too big?) and eventually dropped the ramjet above M=5 ? Also kind of hard to believe, but...
Click to expand...
Look at the rocket section and then compare it to what it took to get the X-51 to Mach 4.8. There's no way the integral booster of ASALM had enough impulse to get it to mach 5+. Given that it was a ramjet and not a scramjet it likely only had enough impulse to get it to a high enough speed for the ramjet to take over.
Click to expand...

Agree. Hard to believe, either way...
There could as well have been a malfunction in airspeed measurement and/or telemetry.

seruriermarshal said:
No malfunction reported , It stop after exhausting its 240-second fuel supply .
Click to expand...

Sorry we were talking about the (reportedly) M=5.4 flight of ASALM in the late 70's, not the recent X-51 flight.
 
bipa said:
There could as well have been a malfunction in airspeed measurement and/or telemetry.
Click to expand...

Unlikely. Tests are measured/observed with multiple independent systems.
 
Looks like the X-51 flight test program has been completed, but we don't know whether the USAF ever plans to develop a hypersonic cruise missile based on the X-51. Even if the USAF doesn't, Boeing may want to consider using the X-51 technology to develop a passenger aircraft able to fly from Los Angeles to Tokyo in just 1 hour.
 
Vahe Demirjian said:
Looks like the X-51 flight test program has been completed, but we don't know whether the USAF ever plans to develop a hypersonic cruise missile based on the X-51. Even if the USAF doesn't, Boeing may want to consider using the X-51 technology to develop a passenger aircraft able to fly from Los Angeles to Tokyo in just 1 hour.
Click to expand...

I wouldn't hold your breath.
 
Someone was reading too much PopSci backissues from late 80s...
 
bipa said:
On the thermal aspects... On my calculator, total temperature @ M=5.4 and 12,000 m should be about 1100-1200°C (2000-2200°F).
It may leave you with a wall temperature around 1000-1100°C (1800-2000°F).
Click to expand...

FWIW, it appears you are using perfect gas relations in your computation. The error due to the caloric imperfection at this temperature is close to 200F. See for yourself at: http://www.grc.nasa.gov/WWW/BGH/machu.html Note that the total temperature in the combustor is going to be much higher due to the additional energy due to combustion.
 
From Ares;

This week’s mission began when the X-51A was released at 10.55 am on May 1 from a U.S. Air Force B-52H flying at 50,000 feet. Following release, a solid rocket booster accelerated the vehicle to about Mach 4.8 before the booster and a connecting interstage were jettisoned after 26 seconds. The vehicle accelerated to Mach 5.1 powered by its Pratt & Whitney Rocketdyne SJX61 dual-mode ramjet/scramjet, which burned all its JP-7 jet fuel over 240 seconds. The X-51A then made a controlled dive into the Pacific at the conclusion of its mission.
-------------------------------------------------------
Bolding mine;

As I have stated before why not have an interim strike missile solution based on a two stage, boost, glide, boost to impact missile (so impact is at a very high speed for maximum penetration) at the Mach 5 range deployed ASAP based on existing technology and then have it followed later with an airbreathing SCRAMJET?
 
bobbymike said:
As I have stated before why not have an interim strike missile solution based on a two stage, boost, glide, boost to impact missile (so impact is at a very high speed for maximum penetration) at the Mach 5 range deployed ASAP based on existing technology.
Click to expand...

That is exactly what an inquiry to a proposed AHW follow on was isn't it? I think I posted that maybe under the Prompt Global Strike thread?
 
DSE said:
bobbymike said:
As I have stated before why not have an interim strike missile solution based on a two stage, boost, glide, boost to impact missile (so impact is at a very high speed for maximum penetration) at the Mach 5 range deployed ASAP based on existing technology.
Click to expand...

That is exactly what an inquiry to a proposed AHW follow on was isn't it? I think I posted that maybe under the Prompt Global Strike thread?
Click to expand...

I was talking about a an air launched strike version should have been more specific but I am all for the AHW as well.
 

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