Scramjet sets hypersonic flight record X-51A

**xinhui** · 27 May 10,, 16:37

Scramjet sets hypersonic flight record
Test flight lasted more than 10 times longer than previous record

Scramjet sets hypersonic flight record - Space.com- msnbc.com

An experimental aircraft has set a new record for the longest hypersonic flight after streaking across the sky Wednesday for more than three minutes while flying at Mach 5 — five times the speed of sound — the United States Air Force has announced.

The vehicle, called the X-51A Waverider, dropped from a B-52 Stratofortress mother ship while flying over the Pacific Ocean just off the southern California coast. It successfully ignited an air-breathing scramjet engine than accelerated up to Mach 5, Air Force officials said in the announcement.

The entire test flight lasted just over 200 seconds, more than 10 times longer than the previous hypersonic record (just 12 seconds) set by NASA's X-43 vehicle in 2004.
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"We are ecstatic to have accomplished most of our test points on the X-51A's very first hypersonic mission," said X-51A program manager Charlie Brink of the Air Force Research Laboratory at Wright-Patterson Air Force Base in Ohio, in a statement. "We equate this leap in engine technology as equivalent to the post-World War II jump from propeller-driven aircraft to jet engines."

X-51A's new record
Wednesday's test flight was aimed at evaluating the X-51A's scramjet engine, thermal protection, stability and control, and other systems.

With a profile that gives it a shark-like look, the X-51A scramjet cruiser is 14 feet (4.2 meters) long and is virtually wingless. It is designed to ride the shockwave it creates during flight, leading to its nickname "Waverider," the Air Force has said.

Pratt & Whitney Rocketdyne built the SJY61 scramjet engine at the heart of the X-51A cruiser.

The Air Force began Wednesday's test at 1 p.m. EDT, when the B-52 Stratofortress hauling the X-51A took off from Edwards Air Force Base in California. The X-51A test craft dropped from its mother ship while flying 50,000 feet (15,240 meters) over the Point Mugu Naval Air Warfare Center Sea Range on the Pacific Ocean.

Four seconds into the flight, the X-51A's solid rocket booster – actually an adapted Army Tactical Missile booster – accelerated the experimental aircraft to Mach 4.8 before being jettisoned to let the scramjet engine take over.

After the flight, the vehicle was expected to splash into the ocean. There were no plans to recover the craft, according to the Air Force.

"Now we will go back and really scrutinize our data. No test is perfect, and I'm sure we will find anomalies that we will need to address before the next flight," Brink said. "But anyone will tell you that we learn just as much, if not more, when we encounter a glitch."

The test was actually the third flight of the X-51 vehicle; it was the first time it flew independently. It had remained attached to its mother ship on both earlier flights.

Three more X-51 hypersonic tests flights are scheduled for later this year. The Air Force has built four X-51A cruisers in all, with one of them now successfully flown.

The project is a joint effort by the Air Force Research Laboratory, industry teams and the Defense Advanced Research Projects Agency.

Going hypersonic
Hypersonic flight, typically defined as beginning at Mach 5, is more challenging than supersonic flight at lower speeds because of the higher temperatures and pressures involved with the faster flight speed. The speed of sound, Mach 1, is about 760 mph (1,223 kph) at sea level.

Conventional turbine jet engines can't handle such speeds, Air Force officials said.

But scramjets, air-breathing jet engines driven by supersonic combustion, like the one on X-51A have their own challenges too. Air Force project officials compared it to "lighting a match in a hurricane and keeping it burning."

The X-51A is not the U.S. military's only project undergoing tests this year.

**bigross86** · 27 May 10,, 18:01

Could they mean longest Hypersonic flight in atmosphere? Surely the space shuttles and the Apollo/Gemini missions flew at much faster than Mach 5.

**zraver** · 27 May 10,, 19:10

Originally Posted by bigross86

Could they mean longest Hypersonic flight in atmosphere? Surely the space shuttles and the Apollo/Gemini missions flew at much faster than Mach 5.

They were not air breathing, but rocketry.

**bigross86** · 27 May 10,, 19:43

An experimental aircraft has set a new record for the longest hypersonic flight after streaking across the sky Wednesday for more than three minutes while flying at Mach 5 — five times the speed of sound — the United States Air Force has announced.

I don't see anything in there about air breathing, but I'll take your word for it...

**highsea** · 27 May 10,, 20:09

Originally Posted by bigross86

I don't see anything in there about air breathing, but I'll take your word for it...

That's what a scramjet engine is.

**Stitch** · 27 May 10,, 20:23

I think the key word in that sentance was "aircraft"; the Space Shuttle and the Mercury/Gemini/Apollo spacecraft are not "aircraft".

**bigross86** · 27 May 10,, 20:37

I may be picking on words, but they said it set the record for longest hypersonic flight. It didn't mention aircraft, engine type, or anything like that.

It's a pet peeve. I hate it when articles don't say things properly, misquote, or just get their facts plain wrong. They should do their damn research. I try and research every single thing I post here on WAB, and I'm lucky if 100 people read what I say. If someone writes something that gets published in the mass media, and they get paid for it too, they should damn well make sure their reports are accurate

**highsea** · 27 May 10,, 20:44

Originally Posted by bigross86

I may be picking on words, but they said it set the record for longest hypersonic flight. It didn't mention aircraft, engine type, or anything like that.

read it again...

Originally Posted by xinhui

Scramjet sets hypersonic flight record

... It successfully ignited an air-breathing scramjet engine than accelerated up to Mach 5, Air Force officials said in the announcement.

...Wednesday's test flight was aimed at evaluating the X-51A's scramjet engine, thermal protection, stability and control, and other systems.

With a profile that gives it a shark-like look, the X-51A scramjet cruiser is 14 feet (4.2 meters) long and is virtually wingless. It is designed to ride the shockwave it creates during flight, leading to its nickname "Waverider," the Air Force has said.

Pratt & Whitney Rocketdyne built the SJY61 scramjet engine at the heart of the X-51A cruiser.

**bigross86** · 27 May 10,, 20:55

An experimental aircraft has set a new record for the longest hypersonic flight after streaking across the sky Wednesday for more than three minutes while flying at Mach 5 — five times the speed of sound — the United States Air Force has announced.

That's the first thing people read, and lots of people don't go further than the first couple paragraphs into an article.

**highsea** · 27 May 10,, 21:03

You've lost me.

You were complaining that the article didn't mention the engine type, the fact that it was an aircraft, it wasn't saying things properly or the author was misquoting, and you only read the first paragraph?

**gunnut** · 27 May 10,, 21:39

Space shuttle doesn't fly...it glides...just like gargoyles.

**bigross86** · 27 May 10,, 23:59

I read the whole article. What bugs me is that in many articles people just skim the first paragraph or two to get the general picture, and too often reporters concise the the article into the first two paragraphs and leave things out, or in other cases just get things plain wrong.

Last week someone posted an article in one of the Iran threads which stated that the Popeye was an American missile (It's Israeli) and that the Chinese aircraft involved in the EP-3 incident where clearly sporting Israeli Python 3 missiles which in reality were Chinese made PL-8 missiles.

In this specific instance, my beef is that the first sentence mentions nothing about Scramjets, and I guarantee you that there will be someone who will read that article and be convinced that the Space Shuttle flies at less than Mach 5. It may not be someone here because most of us here are either former Military or defense professionals, or military enthusiasts and know better, but someone will read that article and draw said conclusion about the Space Shuttle.

It may be a petty argument, but when I read something I like to know the facts are relevant and true, and too often I have to research an article since something doesn't sound right, or I happen to know that something the author claims is wrong. If someone is already getting paid to report stuff that millions are going to read, they should take the extra amount of time to properly research. Most of the time a quick search on Wikipedia is enough for me to find out about something, whether it's true or false. Yes, Wikipedia needs ot be taken with a grain of salt, but at least Wikipedia has sources and a bibliography of sorts. With written articles we need to take the author's word, and too often that word is worthless

**highsea** · 28 May 10,, 16:51

Originally Posted by bigross86

...In this specific instance, my beef is that the first sentence mentions nothing about Scramjets

Um, the title of the article was "Scramjet sets hypersonic flight record".

I think you are setting the WAB record for grasping at straws here.

**bigross86** · 28 May 10,, 17:06

I may be grasping, but definitely not setting the record. I can mention a fair number of em-members who were a lot worse at this than I am.

In this case I may be grasping, but my general complaint still holds true...