The X-51a WaveRider flies...

[RanulfC]

mlorry wrote:
I wasn't aware they even got to testing any hardware on that, it always seemed to me to be a paper study rigged to prove the impossibility of RLVs.

Link to a paper/briefing here that goes into detail on the engine testing done for RASCAL of the MIPCC system:
http://ftp.rta.nato.int/public//PubFullText/RTO/EN/RTO-EN-AVT-150///EN-AVT-150-02.pdf

Also some other possible engine cycles that might be interesting.

Oh yes, we'd often wondered (IIRC) about the use of the Pratt&Whitney F100s that were baselined for RASCAL? The answer was/is rather simple; Cheap and Easy to get. A lot of the P&W F100s have been removed from use and are in storage since the F-16 fleet "mid-life upgrade" program installed higher power GE versions.

My thinking is that while having a lot on storage and available for "sale" and or canibalization for parts it might have been better to go with the higher thrust GE version than the P&W engine. (23,830-29,100lbs for the former series, 25,735-29,100 for the later series)

In fact the United Arab Emirates’ Block-60 F-16 are fitted with the most current GE engines (F110-GE-132) which are rated to a maxium thrust of 32,500lbs. (GE notes that 36,000lbs is possible with some modifications http://www.geae.com/engines/military/f110/f110-132.html)

Randy

[JohnFornaro]

On searching this forum for the term "scramjet" one gets back three pages of results.... Evidently the forum community disagrees with you, Jim.

Evidently the forum community discusses it for three pages.  The number of existing scramjet launch vehicles is still pretty low, largely because discussions differ from demonstrations.

It's still a pretty cool vehicle.  As to "only Mach 5".  Well.  You just can't satisfy some people.  I say, sonic boom, schmonic boom.  Get used to it...

That report was pretty cool.  P.6: about 780 miles in 8 munutes at Mach 10.  When it absolutely, positively has to get there in the next ten minutes.  P.7, Cons:  "Some R&D needed."  Whew.  A lotta R&D would sound expensive, this sounds quite affordable.

I like the airframe shape.  Finally P.23: compares to Wright Brothers plane.  Now that's an apple to apple comparison!  Just teasing.

[PeterAlt]

I don't see anyone here talking about yesterday's test flight of the X51A. In fact, I can't find any news coverage about it anywhere, so I don't know if the test was successful or not.

The X51A is an unmanned test craft, designed to be launched on the belly of a B52 bomber. Its purpose is to test scramjet engines. The tests are being overseen by DARPA.

I've long been a proponent of developing scramjet technology, hence my avatar of the cancelled X30 program that was going to be the first to fly scramjet engines on a spaceplane. If scramjet engines can be proven flight worthy and sustainable, they could be used in a future orbital vehicle, radically reducing cost to orbit.

[Jim]

If scramjet engines can be proven flight worthy and sustainable, they could be used in a future orbital vehicle, radically reducing cost to orbit.

The first two items do not guaranteed the following two, especially the last one.

[PeterAlt]

Do you know if the test was a success or was it a failure? I know previous tests (of scramjet engines) have not so lucky.

[PeterAlt]

If scramjet engines can be proven flight worthy and sustainable, they could be used in a future orbital vehicle, radically reducing cost to orbit.

The first two items do not guaranteed the following two, especially the last one.

I chose my words carefully. I used the words "if..." and "...could...", no absolutes like "will", but we will never know until technologies like these are thoroughly studied and tested...

[jjnodice]

I don't see anyone here talking about yesterday's test flight of the X51A. In fact, I can't find any news coverage about it anywhere, so I don't know if the test was successful or not.

The test is scheduled for today, August 14.  So you haven't missed it yet.   

[Chris Bergin]

BBC article on Waverider:

http://www.bbc.co.uk/news/technology-19257769

[LegendCJS]

Further, I really doubt this is anything but a military toy and research funding sinkhole. A rocket may have lousier ISP than a scramjet but can also operate with less drag (no air inlet) and operate in very thin atmosphere for part of its mission with virtually no drag at all, plus thrust to weight ratio of a rocket is much better and mass fraction too. I don't think it is straightforward that this scramjet thingy would perform better than a rocket on the same mission. If ground targets need to be hit, rockets offer the benefit they might go supersonic all the way down, imparting significant kinetic energy too. The inlet of a scramjet would work as a drag chute at anything significantly below its design speed, probably slowing the thing to subsonic at sea level.

Every long range missile I can think of is multi-stage.  All your concerns about the performance of a scramjet on the last dive to a target are moot if the scram jet is only used as a cruise stage, with the warhead carried on a final rocket stage.  In fact I think this would be required for all designs in order to achieve accuracy: the boxy scram jet looks hard to steer.

[john smith 19]

So after 5 decades of designing *vehicles* to use this concept somebody has actually tested it for a *reasonable* duration.

It's very clever engineering. It's only in the last 10 yrs people have managed to make Thrust *exceed* drag on these things, so that's pretty impressive development.

Like all solid systems it's likely to make quite a good weapon system, but as an LV my intuition tells me Xcorp will be launching payloads before *anything* using this concept gets to orbit and Skylon will be carrying *passengers* before anything crew rated vehicle with this propulsion system leaves the runway.

This test vehicle is a *fixed* speed test. It's useless for the accelerator mission of an LV. I don't think *anyone* is talking about the variable geometry necessary to give an actual *range* of speed. And of course there's the little matter that this thing has *no* thrust at 0 speed. I know there have been TBCC and RBCC development programmes which *should* cover this but how far has any of them got?

It's big attraction are really that it's a high speed vehicle that does use air and does not use *Hydrogen* and a flight profile that won't spook countries in the same way a re-purposed ICBM flying over their territory will. Whatever the unit price would it likely to be *lots* cheaper than a Trident.

[PeterAlt]

I've been waiting for the scramjet to be validated ever since X-30 program back in the early 80's (depicted in my avatar)!

The X-30 was an overly ambitious program aimed at demonstrating the scramjet engine, new composite materials, and other new technologies, and do so by creating a sleek piloted SSO spaceplane. Billions were spent before it was cancelled and it never got to fly. The new composite materials were developed and used in later programs. Ground-tested scramjets were built and tests were run.

Later X-plane programs continued developing the scramjet were the X-30 left off. This program is a continuation of a string of lesser ambitious programs, but focused on developing and flying scramjets. The idea is that the scramjet could accelerate a spaceplane initially before more traditional rocket engines are used that could kick it into orbit. Imagine a plane that would take off on a runway and "fly" to LEO, return on a runway, refuel, and take off again. Quick turnover and extremely cost efficient!

[LegendCJS]

I saw a blurb saying that at least the carrier plane took off yesterday.  That is all I've seen.  Anyone?  For a story that got splashed across the headlines of a couple major news sites to go to the kind of silence I saw yesterday is a bad sign.

Edit: Just saw a head line from Wired Business Insider referencing a tweet from WIRED saying the test was a total failure??

[Chris Bergin]

I don't see anyone here talking about yesterday's test flight of the X51A. In fact, I can't find any news coverage about it anywhere.

That's because you never bother to look and always start new threads.

Merged thread, with the one that was two threads down from the one you started on this very section.

[savuporo]

Edit: Just saw a head line from Wired Business Insider referencing a tweet from WIRED saying the test was a total failure??

Twitter at   http://wired.com/dangerroom
Danger Room ‏@dangerroom
Bad news for the USAF's mach 5 missile. X-51A failed its flight test; a fin problem caused a loss of control b4 the engine could kick in.

I guess we'll wait and see, the results were supposed to be announced today.

[Chilly]

Aviation Leak doesn't really offer much more either: http://www.aviationweek.com/Blogs.aspx?plckBlogId=Blog:27ec4a53-dcc8-42d0-bd3a-01329aef79a7&plckPostId=Blog%3a27ec4a53-dcc8-42d0-bd3a-01329aef79a7Post%3a364ef945-4d56-499f-9359-f205eca3e0bf

The same information, yet more verbose. That could be a marketing tag...

[savuporo]

Here we go http://www.wired.com/dangerroom/2012/08/x-51a/
"Military’s Mach 5 Missile Fails, Again"

[JohnFornaro]

What's the point of that barrel roll in the "telegraph" video linked to the "wired" article?

[PeterAlt]

I don't see anyone here talking about yesterday's test flight of the X51A. In fact, I can't find any news coverage about it anywhere.

That's because you never bother to look and always start new threads.

Merged thread, with the one that was two threads down from the one you started on this very section.

Chris, the thread I started was created before this one, which is why my thread was a few lines down. Look at the times the two threads were created, and you will see the one I create preceded the other. Thank you for merging the threads, which was needed, any way.

[GClark]

What's the point of that barrel roll in the "telegraph" video linked to the "wired" article?

I don't entirely understand it, but my (admittedly failing) recollection is that the intake has to be on top for the engine to start.  Once it has started, it then rolls back upright and the mission (hopefully) continues.

[JohnFornaro]

Thanks, but I still don't get it.  The "wave" is under the vehicle.  That's where it gets combustion air from.  Maybe I don't understand the starting process?