Slashdot Mirror
NASA Prototype Plane Scheduled To Attempt Mach 5+
Logic Bomb writes: "Mach 5 -- 5 times the speed of sound, or 5000 mph -- is a speed that so far has eluded jet-powered aircraft (the existing record for a production craft is about mach 2.1). NASA, however, has high hopes for its latest attempt, the X-43A. Using a booster rocket, the prototype will be accelerated to mach 5, at which point its engine will be scooping enough oxygen to power the craft at those speeds on its own. Hopefully, it will fly at speeds up to almost mach 7 for 10-15 seconds before shutting off and plunging into the Pacific. An article from the Los Angeles Times has more details." Not to be confused with the X-33 and X-34 projects.
Aurora, a Mach 5+ plane, has been flying for years. The public just hasn't been told yet. Just like it was with the F117 Stealth bomber.
Speed Racer was able to get to the Mach 5!
If you want to find out how fast the speed of sound is at different altitudes, check this out: Interactive Atmosphere Simulator
The original post does have incorrect numbers (mach 7 ~ 5000 mph) It depends heavily on altitude. At sea level mach 7 is ~ 5300 mph. At 60,000 feet, mach 7 is ~4600 mph.
I used to live in Utah where they kept one of the SR-71 Blackbirds in an aviation museum. Part of the tour was that they told us that the jet was designed to stretch as it got hot to allow for heat expansion, and that it stretched about a foot while flying at high speed.
They also said that when the museum got the thing, it's speed meter(i forget the technical term for that on an aircraft) was jammed at it's max. displayable velocity, which was Mach 7.
Well, the LA Times article was so full of, umm, small errors, that it's hard to know where to start. Yes, a hypersonic bomber is unlikely, but a hypersonic replacement for the SR-71 would be very useful.
Mass fractions are all you have to look at to wonder why Single Stage To Orbit [SSTO] is some perverted NASA priority.
My strong impression has been that NASA management hates SSTO and was dragged kicking and screaming into the DC-XA (follow-on to the successful DOD DC-X project) and X-33 projects. But not to worry, NASA has now "proved" that SSTO doesn't work by canceling the X-33 project.
I knew 2 SR-71 pilots years ago and one told me that he had seen MACH 4. He told me that he had been told by several other pilots the they had gone *MUCH* faster but he would not say what *MUCH* really was. I always *assumed* that he meant MACH 5 or faster. While he never confirmed anything beyond that speed (MACH 4), I have no doubt that its top speed is at least MACH 5. Otherwise, why would it's top speed still be classified????
I recall reading the fastest a MiG 25 was clocked by the west were MiG-25 recon birds flying out of Syria and chased by Israel F-4s. I'd read that they were clocked at Mach 2.7.
The MiG-25 was designed not to fight the F-15, but to intercept the XB-70 bomber, which was a Mach 3+ high altitude delta wing bomber, like a nasty Concorde with nukes. The XB-70 was canned and then development started on the B-1B, but the MiG-25 continued. The F-15 was actually designed to beat the MiG-25...not the other way around.
You didn't really have to. It is a fairly well known fact that sound carries much better over water, and especially when there's heavy fog... seems like you can hear little creaks and bumps from miles around. And anyone who ever read basic undersea explorer books or warm & fuzzy stuff about the lives of dolphins probably knows that sound goes even faster _under_ water, where the carrier matter is denser.
"Hot lesbian witches! It's fucking genius!"
Maybe I'm too old to be reading slashdot but the SR-71 achieved mach 3 and used the same "scooping enough oxygen to power the craft at those speeds on its own". They called it a ramjet. Reinventing the wheel is yet another fine use of our 39% tax bracket that the Clintons invented.
Actually, the SR71 uses a hybrid turbojet/ramjet engine. At low speeds the engine acts like a standard turbojet; as speeds rise the engine begins to act more like a ramjet. Here is some good info and pictures.
Here are a couple good pictures of ramjet and scramjet engines. A scramjet is just a form of ramjet that only works above mach 1.
The pegasus drops from a plane.
2 .j pg
So far, mostly a modified L-1011.
http://www.vafb.af.mil/image_gallery/Images/Peg
These are my friends, See how they glisten. See this one shine, how he smiles in the light.
mach 3+ for sufficiently large values of +.
The other thing this plane was specifically designed to do was fly VERY long distances on small amounts of fuel, due to the special design of the engines, type of fuel, etc.
These are my friends, See how they glisten. See this one shine, how he smiles in the light.
yeah, here we go;
mach 3+ for sufficiently large values of +.
The other thing this plane was specifically designed to do was fly VERY long distances on small amounts of fuel, due to the special design of the engines, type of fuel, etc.
"normal" supersonic jets can go supersonic, but you're talking about going through half your total fuel supply in a matter of minutes. The SR-71 sustained these speeds for hours, over thousands of miles.
The newer F-22/F-23 generation of jets was supposed to have this new "supercruise mode" which allowed extended operation at supersonic speeds without such a heavy fuel penalty.
Unfortunately, it was another boondoggle for a defense contractor looking for big government handouts. Which they got anyway.
These are my friends, See how they glisten. See this one shine, how he smiles in the light.
a mach 5 plane would be a sucker for a laser.
These are my friends, See how they glisten. See this one shine, how he smiles in the light.
Except for 280 million Americans. For some reason the US decided to resize certain measures. E.g. American ton is 2,000 lbs instead of 2,240 lbs, and the American pint is 16 fl. oz. instead of 20 (making gallons smaller, and of more interest to me, beers). This plus inconsistency with mixing with metric measures makes it hardly surprising that the Mars project lost that probe last year (or the year before).
"Of course it may be that journalists are the blame in this case.
I'd agree with that. The first place I heard the US billion commonly used was on the news broadcasts on the television. It slowly crept in until it is was the de facto standard.
Of course, we also have the idiot journalists to thank for celebrating starting a new millenium a year too soon.
Ultimately you could blame lack of funding in education that results in people not being confident enough in their knowledge to disbelieve the journalists, and not being able to tell the difference between local and imported American culture.
Concorde can fly at mach 2.01. That's almost the mach 2.1 mentioned above, and it's a *commercial passenger airliner*. I find it rather hard to believe that the military aircraft in production don't go much faster! People need to get their facts straight before spouting off technical details and trying to sound clever.
http://www.concordesst.com/performance.html
The MiG-25 FoxBat (similar to F15) does mach 2.5+ (probably more like mach 3).
While that may be true, the Russian pilot that flew his FoxBat to Japan in the 70s said that they could not stay at M2.5 for very long because their engines would get too hot and sieze up. As a result, anyone who tried to go that fast would be subject to disciplinary action. It was more for chest thumping and to be able to claim that their main interceptor was faster than the US F-15.
As far as taking several states to make a banked turn, that depends on where the turn is being made. I can see that being the case for the Northeastern states. I would think they could make a U-turn within the state of Nevada.
the good ground has been paved over by suicidal maniacs
You are correct. According to aerospaceweb it first flew in 1964. At 42000, it could do 2110 mph and 650mph at sea level. The F-15 first flew in 1972 and can only do 1665 at 36000ft.
the good ground has been paved over by suicidal maniacs
The issue was that at the time, there just weren't any other materials that could be used to seal it that could withstand the heat et al later on in the flight. Rubber would never make it. In fact, they had to build the thing largely out of titanium which ironically was all imported from the Soviet Union. Lockheed had to learn a lot about how to work with titanium in a hurry, as I recall.
The scary thing is that the SR-71 (originally RS-71, but LBJ transposed the letters) was developed in the 60's, the F-117 in the 70's and the B-2 in the 80's. God knows what they've got now, and when we'll be let in on it.
-- This and all my posts are in the public domain. I am a lawyer. I am not your lawyer, and this is not legal advice.
Hardly. Production aircraft have no problem beating Mach 2.1. The F-16 and F-15 are both mid-Mach 2 capable, the F-111 can easily tickle the bottom side of Mach 3, and the SR-71's official speed is over Mach 3 (with unofficial speed being probably closer to Mach 4)
Mach5 is not 5000 mph or 5000 fps as many have suggested. It is 5000 km/h. You know, kilometers, the unit of length that the rest of the world uses but US somehow refuses to acknoledge? But hey, it doesn't even surprise me any more after NASA crashed a satellite because they fucked up unit conversion...
___
___
If you think big enough, you'll never have to do it.
I'm not anti-millitary or anything, but doesn't it strike anyone as a bit twisted that with almost any new or improved technology the millitary's always standing by thinking of how it can help them kill people more efficiently? This just kind of bothers me.
On a side note, doesn't the whole mach5+ thing seem a bit pointless? Someone in an above post thought engineers shold spend more time building aquatic habitats or something. But sticking to the aerospace subject, instead of working to make the NY-LA trip 30 minutes, wouldn't it be much cooler if flight times stayed the same but the price was a lot cheaper? How cool would it be if you could do cross country for $50, $100 round trip. Want to fly down from NY to New Orleans for the weekend? $20! Now that would be useful. Who cares if a few elite rich people (or business people with big expense accounts) can get across the country in half an hour. I say make the safest form of mass transit (or any transit really) actually available to the masses. Just my $0.02
Unfortunately, I don't have the original copy of this, so I'm doing it from memory. Possibly urban legend, but funny none the less. This was overheard on a west-coast Air Traffic Control frequency:
pilot: Request permission for FL85 (FL85 is 85,000 feet; far above the service ceiling of almost all aircraft)
ATC: if you think you can reach it, sure thing; it's all yours
SR-71 pilot: Roger, descending from FL100
Read the article...
"As such, the X-43A will be mounted to an Orbital Science Corp. Pegasus rocket, which boosts the aircraft to the required speed, or about Mach 5 or greater. [...] For the test flight, a modified B-52 bomber with the X-43A attached to the wing will fly to the California coast from Edwards and launch the aircraft along with the booster rocket near San Nicolas Island southwest of Los Angeles. The B-52, built in the 1950s, is one of the oldest around and has been used on some of the most important projects in aerospace history including the air launch of the X-15 and other experimental wingless aircraft."
Also, I don't see where you get that the X-43A doesn't have to carry it's own fuel, either. Even though it gets a rocket powered assist from a rocket that gets a jet-fuel powered assist, it still carries fuel of it's own.
Does this person even know what they are talking about? First off, the speed of sound is roughly 760 Mi/Hr at sea level, but it depends entirely on the density of the medium the sound is travelling in. At altitude, where aircraft perform best, the speed of sound is roughly 640 mi/hr (again, depending on density). Production jet powered aircraft have been travelling faster than Mach 2.1 since the 60's. Aircraft, off the top of my head, that travel faster than this are:SR-71, F-14, 15, MiG-23, 25, 29, 31, Su-27, 30, Mirage III, and Panavia Tornado. And that's just the unclassified stuff.
like my X10 firecracker module can? :-)
-- Thrakkerzog
Sounds like a perfect candidate for a Sundive vessel ala HGTTG. "It means," said Marvin, "that the ship os going to dive into the sun. Sun ... Dive. It's very simple to understand. What do you expect if you steal Hotblack Desiato's stunt ship?"
Chapter 21 The restaurant at the end of the universe
In Europe billion is 10^12 (trillion 10^18). We have milliard (10^9), but beside that, every magnitude above thousand is 10^(6*x) where x comes from greek or latin.
I think US uses trillion for what we Europeans use billion for. I don't think US can do anything where trillions of dollars are an issue.. Of course it may be that journalists are the blame in this case.
Is this really of any use? We all know that anything that moves this fast will be in extreme slow motion.:).
The sonic boom is only produced at the precise moment where the speed of travel for the plane is equal to the speed of sound. At that speed, the sound waves emitted over a period of time "bunch up" and hit together, causing a sonic boom. However, this doesn't apply once the speed gets above the speed of sound - in fact, the faster above the speed of sound that the plane gets, the less of a sonic boom effect it will produce. After Mach 2, the sonic boom effect will be less than if it were standing still.
The shockwave is only a _plane_ when you're at exactly Mach 1. However, you still do indeed get a shockwave at higher speeds. It's a cone instead of a plane, that gets a narrower and narrower aspect ratio as the plane travels faster (the cone expands radially at Mach 1, but the tip [the plane] is moving much faster).
Draw the tip of a stick across still water and watch the ripples to see what I mean. Try this at different speeds (from very slow to very fast).
As it's still a shockwave - an abrupt (discontinuous) change in the velocity and density of the air - it'll still sound like a thundercrack, and will still break windows, because it deposits all of its energy at once (when the shock passes the listener/window).
You'll actually get _more_ damage at higher Mach numbers, because the energy shed into the atmosphere is roughly proportional to the cube of the plane's speed (one of the reasons heating's a problem in hypersonic craft).
For quite a while there have been persistent rumours of a US military aircraft that flies at Mach 5 using liquid methane as a fuel. That would nix the "first aircraft to travel at this speed" claim.
Are there actual records of the US craft's existence, or does it remained a rumour?
Mebbe Whooooosh is the word of the day.
The 80's era project referenced was the X-30 which was also known as the "NASP" or "National Aero-Space Plane". The idea was to have a plane that takes off, boosts to very high speed using SCRAM jets, and finally uses a small rocket boost to reach suborbital velocity. After a cruise above the atmosphere it would reenter to land. The quote that comes to mind is, "New York to Tokyo in two hours."
Unfortunately, like many gov't projects, it ran so far over budget that it was finally canceled. The high speed flight researchers have been trying to recover ever since. The new approach is to use small technology demonstrators to make incremental discoveries rather than putting all the eggs in one basket. Sadly, the gov't didn't learn with the X-33 project which had the same failing.
World Beach List, my latest project.
The speed of sound is approx 720 mph at sea level, and reduces with altitude.
The SR-71's top speed record was Mach 3.24, which is still the record for air breathing propulsion powered aircraft. (Of course there've been plenty of rumors of top secret planes even faster.)
The F-15 can fly Mach 2.5 at high altitude, & many current fighter aircraft can fly Mach 2.1.
The X-15 (which was rocket powered) reached speeds of over Mach 7, which was the fastest human piloted aircraft ever. The space shuttle reaches Mach 25 (~17,000 mph) in order to reach orbit.
Warp .02 or impulse 7e-6 in Trek lingo.
Imagine all that relativistic shifting!
Yup. (Yes, folks, isn't it astonishing!? Someone posting to Slashdot who actually admits that he doesn't know everything! Wow! Better mod this up!)
But "people who read aerodynamics textbooks" are still guessing, no matter how knowlegeable those guesses are. Educated guesses about classified perfomance is pretty much irrelevant to "the record". By definition, any such flights -- if they happened -- are off-record.
The SR-71 program cost a tenth of what the recon satellites cost. The SR-71 was an amazing aircraft, but not as terribly difficult to operate as you make it sound. It was extremely reliable relatively cheap, and effective. Given the lack of decent reasons to shut the program down, certain persons have speculated that there may be a secret successor program....
Mod down posts with a "Free Mac Mini/iPod" sig, they're spam!
If you're such a saint, then go fix these things yourself.
Mod down posts with a "Free Mac Mini/iPod" sig, they're spam!
F = ma. It's all a matter of acceleration, not top speed.
For example, on the surface of Mars the speed of sound is really slow (180mph, if I recall correctly.. it's been years) and it has the rough equivalency of 180,000 feet (1/3 earth atmospheric density). So for a plane to reach 100,000 feet is quite amazing. Not busting out 5x the speed of sound when the speed of sound is only 900mph.
And, I'm not sure if you realize this but flying a supersonic aircraft requires different aerodynamics than one that flies subsonic. Look at the concord for a good example of this. While flying at supersonic speeds, it is a much more painstaking process to alter your course. Hence, the broad turning radius.
As for the folklore stuff, a lot of that stuff is just rumors and myths. A lot of it is based in fact, but gets the broken telephone effect unfortunately.
And, the reason why 'All this bullshit' is because a plane flying that high is untouchable. Period. Assuming you do pick it up on radar, what are you going to shoot it down with? This plane could be creeping at 200mph at ceiling and it still is relatively safe. It's a surveillance aircraft, they aren't looking to blast over their target so fast they only get a few seconds of images. There was a myth about mounted satellite guns/missiles (heard both) but I have no idea about the validity.
Dacels Jewelers can't be trusted.
Reinventing the wheel is yet another fine use of our 39% tax bracket that the Clintons invented.
Yeah, after all, it wasn't Ronald Reagan who spent $3.3 billion (just the part not in the "black" budget) on the X-30 National Space Plane scramjet project that never reached a prototype flight. No, it was the Evil Doppelganger Democrat who was really running the White House back then! In fact, while Bill Clinton was Governor of Arkansas, he was secretly controlling President Reagan with his mental emanation telepathy superpowers! Powers Clinton must still be using on Dubya, in an evil plot to make him spend the People's Money (tm), even after January 20, 2001!
The only solution? Aluminum foil wrap around the White House, and tinfoil hats for all Republicans.
By the way, you forgot to include the Clinton Death List (tm). It's not too late to prosecute him for the Lindbergh kidnapping!
----
lake effect weblog
lake effect weblog
{Network engineer in Chicago--looking for work!}
Hey, what can I say?
/found/ lots of alternative fuels...Problem is nobody wants to use 'em.
Things that are big, noisy, dangerous, and fast are just more fun than playing with the fishies.
Or (heaven forbid), they find alternative fuels.
Oh, we've
C-X C-S
Logic Bomb seems to be under the impression that The speed of sound is 1000mph. It's more like 730-750mph last time I checked.... Mach 7 is 5000 mph, not Mach 5.
The mph speeds are correct as stated, but all of the mach speeds are off. The SR-71 does go 2100mph, but thats nearly Mach 3, not Mach 2.1. And the new craft in question which will go 5000mph is Mach 7, not 5.
Just nitpicking here folks, but someone should clarify this....
-Julius X
-Julius X
remove "-whatkindofspamdoyoutakemefor-" from email to send
--
Vidi, Vici, Veni
.2*3600 =~ 720mph.
5000/720 = 6.9 times the speed of sound.
Seeing as the plane "will fly at speeds up to almost mach 7", I think this is a case of a confused submitter.
Interesting, an example of the self-contradictory military mind.
1) They want a bomber flying at mach 5 which will be "too fast to shoot down".
2) They want a missile defense system capable of destroying both theater and ballistic missiles.
Is it just me, or is this another proof of the
oxymoron "Military Intelligence"?
I know, many of the forty-somethings I work with have the same problem...
not to be confused with the X-11 project.
Pope
Freedom is Slavery! Ignorance is Strength! Monopolies offer Choice!
It doesn't mean much now, it's built for the future.
Actually...
though it is true that sound travels faster through dense objects....
The speed of sound through the atmosphere is chiefly regulated by temperature.
The speed of sound at high altitude is quite similar to the speed of sound at sea level, though the amount of drag involved is greatly reduced (this is why the concorde does it's thing at 60,000 feet rather than sea level; too much drag)
. . . in check-in, boarding, and luggage recovery. . . followed by several more hours in traffic outside the airports. . . .
If a laser system can intercept an ICBM, it can intercept this contraption. Their velocities aren't that different.
Keep in mind that the computational fluid dynamics you need to get a scramjet to actually WORK are, well, rocket science. By that I mean really really REALLY phenomenally complicated. There's a reason this has never been done successfully before...computers aren't big enough yet to model this stuff well.
Why yes, I AM a rocket scientist!
Have you any idea how complicated it would be to open a DOOR in the bottom of an aircraft moving at Ludicrous Speed (tm) and drop a BOMB out of it? I'll bet you this shiny nickel that the bomb would bounce right off the shock wave into the aircraft.
GPS guidance for munitions is trivial. JDAM and JSOW both use it, and both are, I believe, either in service or very close to service. JDAM is an iron bomb with a GPS guidance package attached to it, and JSOW is essentially a modest-range air launched cruise missile (~150-200 miles).
Why yes, I AM a rocket scientist!
MiG-25:F-15::dump truck:Ferrari
The MiG-25 was pretty fast, but it couldn't turn AT ALL. It was a mediocre, and very unreliable, interceptor. The MiG-31, with better avionics and uprated engines, was a much less bad interceptor. A crackhead could splash either one with an F-15 though...the Russian avionics are just totally outclassed.
An Su-27, in a dogfight, now THERE'S a good airplane. Payload like an F-15, turn performance like an F-18, I'll take two.
Why yes, I AM a rocket scientist!
You're a nutbag. The sonic boom occurs when the cone-shaped shockwaves coming off the nose and tail of the aircraft cross your eardrums. On most aircraft, you can actually hear two booms...one from the nose, one from the tail, in very quick succession.
Why yes, I AM a rocket scientist!
25 minutes? I think you've slipped a decimal there, bud. More like 2.5 minutes. (Twice that if you've got external drop tanks, and thrice that with drop tanks and FAST packs)
Why yes, I AM a rocket scientist!
Yup. I'm an aerospace engineering student...I'm down wit' da rocket equation, yo. : )
Schlepping all the dead weight of fuel tanks and structure to contain them up to orbit is a huge pain. Staged rockets are (unfortunately) the way to go until we see some radical (like a couple orders of magnitude) increase in engine efficiency. I don't see where that increase is going to come from. Aerospike is great and all, but it's not THAT much better than conventional engine bells.
I wanted so badly for SSTO and air breathing rockets to be viable...then I did the math. Not gonna happen any time soon.
Why yes, I AM a rocket scientist!
Why not just use a rocket the whole way? Assuming the same fuel mass for the scramjet and for the rocket (the efficiencies are way way better for rockets, but we'll give the jet the benefit of the doubt) the oxidizer isn't going to weigh more than the separate engine and fuel system the scramjet's going to require.
Air breathing orbital vehicles are not going to happen anytime soon. The efficiencies just aren't there. Chemical rockets work REALLY well.
Why yes, I AM a rocket scientist!
1: The P-3 Orion is a plane. Its mission is to spy on people, which is what it was doing at the time of the accident. How is this not a real "spy plane" Its a plane that spys isnt it?
Nope. That's a surveillance aircraft. Spy planes are operated by the CIA and piloted by spies. (most U-2 and some SR-71 missions) By definition, a spy does not wear military uniform, and does not travel in vehicles with military insignia. So, no, the P-3 is NOT a spy plane.
Wouldn't this be useful as the first stage of a two-stage system?
Hellz yeah!
Hellz no. The frontal area of a scramjet is much higher than the frontal area of a comparably powered chemical rocket. Wave drag is a bitch, and it's the factor that will continue to kill air-breathing high speed flight for the forseeable future. The engine is also much heavier than the oxidizer that a regular rocket would use. Remember, you still need a conventional rocket to get this thing up to the point where it can light up...
KISS. Keep it simple, stupid. Scramjets are interesting technology, but they're not going to get me to Mars any faster. Heavy lift orbital insertion is 0wn3rzd by chemical rockets.
Why yes, I AM a rocket scientist!
Yup. I was very disappointed that NASP and VentureStar were basically boondoggles, although I hope that aerospike engine technology continues to develop. There's a concept that makes a hell of a lot of sense. DC-X did amazing things with vertical landing technology, but I don't buy it as a viable SSTO system. And landing on a rocket in Earth's gravity well Flash Gordon style is totally stupid. The atmosphere is REALLY good at slowing things down...use it!
I make no claims whatsoever about alternative propulsion technologies. I'm not sure I'm ready to believe that giant railguns are going to be a viable launch system, but in conjunction with laser launch systems...mebbe. The Earth's gravity well is a BITCH.
Why yes, I AM a rocket scientist!
SSTO is not a solution in and of itself. Whatever magic launch system is developed, a staged rocket WILL be more efficient than an SSTO vehicle, in terms of the ratio of fuel weight to payload weight. See, with SSTO, all the plumbing and tanks and stuff that get thrown away from a staged rocket take up weight that could be used for payload.
So, if you can decrease the weight of your structure by an order of magnitude (possible with smart composites engineering, but OBSCENELY expensive) or make enormous strides in engine efficiency (not easy...rockets are pretty damn efficient) SSTO will be possible. SSTO is supposed to win on the maintenance front...it's supposed to be cheaper to refurbish the spacecraft for its next flight than to build another rocket of equivalent power. This goal is the second key to SSTO, and it is far from being realized.
SSTO is not an end in itself. What we REALLY need is inexpensive access to orbit. Some very forward-thinking individuals argue that SSTO is the way to do this, and in the long run they're probably right. I belive that inexpensive rockets are the better alternative, certainly in the near term.
And I AM a rocket scientist. I've got a bumper sticker to prove it. : )
Why yes, I AM a rocket scientist!
No, there are two valid schools of thought on the subject. I happen to disagree with the people you've talked to...but that's OK. : ) My primary interest is low cost per thrown mass. That favors large, efficient spacecraft (Energia and the big Ariane boosters). I believe that the same engineering advances that make SSTO possible (and don't get me wrong...it IS possible. It CAN be done. I think it's going to be hella expensive though) will allow us to make cheap, expendable heavy lift boosters, with off-the-shelf technology (like Shuttle main engines, which are about the most efficient rocket ever devised).
If you're interested in this subject, check out Robert Zubrin's "The Case for Mars". He describes a heavy lift booster that can carry 1.5-2x the payload of the Shuttle (which is currently the USA's heaviest lift vehicle) and cost much less per shot. I didn't want to believe he was right, but he defends his case admirably.
Rockets are very unsexy, and not very interesting to me. I think they require a sort of brute-force unsubtle engineering approach that doesn't pique my interest the way SSTO craft like VentureStar and DC-X do. However, the economics and efficiency of large rockets for heavy lift are tough to beat.
I do believe that there's a niche for a small, three to six-person reusable spacecraft for moving crew (and passengers?) to and from LEO. I hope that the X-Prize brings some more designs into that arena.
Why yes, I AM a rocket scientist!
Airline-like servicability is the Holy Grail of SSTO. I don't know if it's feasible. If it were, I'd like to see those principles applied to Shuttle first as a technology demonstrator. (like replace that goddamn heat resistant tile system...those things SUCK to refurbish!)
One interesting proposal I've read is to use throw-away rockets, but have the engine and avionics sections (the expensive parts) be designed to be recoverable and reusable (IE sorta like the Shuttle's SRBs, only cost effective).
Again, reusability isn't the driving factor. If I design a rocket that costs $1000, and it costs you $2000 to refurbish your SSTO craft for a mission, I win. Does that make sense?
Why yes, I AM a rocket scientist!
At what altitude? What air density? What medium, for that matter? IIRC, the speed of sound depends on all those things.
] D
I heard that Shrubya is looking for a Chinese pilot to make the flight.
The F-22 is the first and only plane which can maintain a speed over mach 2 without afterburner.
The Concorde reaches Mach 2 without afterburner.
This already exists. As a matter of fact it goes from 90 to 0 in less than a second. Any car as a matter of fact can do that, if run into a steel reinforced brick wall.
Something tells me that if you slam into a brick wall at 90 mph, odds are you're not going to get a traffic ticket ;)
Salamander. I saw it last night on a Voyager rerun! The pilot might even come back for George W. and they will have little Salamander babies. I swear. The only reason that Star Trek is even presented as fiction is because the little people can't handle the truth. Which is,we will all be Salamanders in a million years and it is obvious that Mach 5 can be extrapolated into Warp 10.Xcellerated Darwin is upon us. G-d bless Texas and the 49 lilin's -schwaahed
But a rocket isn't a jet
On the subject of triethyl borane, there is a very interesting book on the development of boron based fuels intended for the B-70 bomber: The green flame: surviving government secrecy by Andrew Dequasie. In order for the B-70 to have useful range at mach 3, more energy density was needed than hydrocarbon based fuels could provide, which led to research in various borane compounds. Unfortunately these compounds are extremely dangerous to work with (as the previous poster indicates) and the combustion products include boric oxide (boiling point 1860 C) which tends to solidify on the turbine blades of a turbojet. The project was cancelled along with the XB-70.
First off I agree that it possibly can fly for short periods at mach 4 but much of the reason the SR71 is so weird is that it requires great efficiency for it's long range and it's high ceiling. Wearing space suits has nothing to do with speed and everything to do with altitude. The heat also has more to do with altitude, because there's so little air up high the plane looses very little heat to conduction it therefore must radiate most of its heat away, as a result it gets VERY hot. Actually that may also explain the "non-flamable" fuel. After all you wouldn't want it to spontaniously combust in the tanks.
The West measured the speed of the Foxbats in Syria or somewhere (an air show in Moscow?) with the rador and the measurement was something like Mach 3.0.
As a response to this threat, the Americans developed the F-15. Not the other way around. Note the similar design. (Agian the two-tail-fin two engine design seems to have been perfected by the Su-27/31.)
The Foxbat that flew to Japan was thoroughly analyzed by the Americans (not very much unlike what the Chinese are doing these days) and they concluded that it couldn't do as fast as Mach 3.0. More like Mach 2.5 or so. And the West realized that they were chasing the ghost.
I was 12 or so when the MiG-25 flew to Japan. I remember watching the TV news live. The incident may have had something to do with my becoming an aviation enthusiast later.
I'm Canadian as well and I've heard both used. In school (University of Victoria) billion was used to denote 10^9 almost universally, which I assume is due to the fact that many/most Engineering/Science profs got their doctorates in the US rather than in Canada. What with their TV and radio being shipped up here, it seems that most people go for billion = 10^9 these days.
The "ize" spellings of realise, specialise etc. are now considered fine in British Columbia schools too. That one drives me nuts... it just looks so... American.
The SR-71 uses triethyl borane (TEB) to start. TEB is very volatile and will burst into flames when exposed to air.
Urban legend in the USAF has it that the SR-71 is Mach 4+
Could be... The officially quoted top speed of the SR-71 is "Mach 3+". It all depends on how big the "+" is.
I tend to think that the USAF flew the SR-71 right up to the edge of what it was capable of doing. It was a special-purpose aircraft with highly trained pilots, flying very precise mission profiles. It was designed to do one thing very well (go fast). If it turned out that the SR-71 could go no faster than Mach 3.5 before something horrible happened, I bet the USAF would fly it right at Mach 3.49.
Way back in 1996 on rec.aviation.military, Mary Shaver from NASA Dryden wrote an interesting description of TEB:
TEB is the "igniter" for JP-7. You can't get JP-7 to burn without it in the SR-71, as the ignition of JP-7 takes a higher temperature than is conveniently produced otherwise. You drop in a shot of TEB, which bursts into very hot flames the minute it has any oxygen, and this ignites the JP-7. Once ignited, the JP-7 keeps burning. The plane has twelve shots of TEB (either total or per engine, I forget), using one shot for each engine start and one for each burner light.
I watched them TEBbing the plane once, keeping well back and being careful to not stand between the big green firetruck and the crew. They had a very, very tiny leak between the TEB nozzle and the aircraft fitting and were getting a drop of TEB released about every 20 seconds. These drops would be on fire as they fell, but they (sort of like most meteorites) burned completely before they reached the ground. It was really pretty, but I was glad it wasn't me in the silver fire suit.
TEB requires contact with oxygen to burn. UDMH however, can spontaneously decompose all by itself.
You are correct. Unfortunately I hit "submit" before catching the mistake.
I thought the speed of sound was roughly 730 mph? That would make mach 5 ~ 3600 mph. Somebody correct me if i'm wrong
I think many people are missing the point. Why does the government want a plane that goes this fast? Why one answer should be to out run anti-aircraft defenses. Sure you can always fly higher than a standard flak gun, but not so with a surface to air missile. Why waste effort on a missile counter measure that may or may not fool the missle when you can have a plane that is simply to fast to catch? You get in, strike the target and get out fast, the word is surgical.
The SM2 Block 4 standard missile is Mach 4 plus last time I checked, that is with a directionally fragmenting warhead with 80 pounds of explosives. That should work nicely, oh and FYI the math for the moving target isn't that bad, but hey thats what guidance computers are for. Read up on the AEGIS weapon system, you'll get the picture.
KmPH or MPH has NOTHING to do with aircraft, they dont care how many miles any hour the plane flies. its like asking, whats the airspeed of your car? well, with the wind or against it.
You'd look a bit less silly if you actually read the article before commenting...
Mach is directly related to the (variant) speed of sound, so it is most useful (only useful?) when you discuss Mach 1, when there is a real physical effect. Above that, everything is gravy.
--
"It's tough to be bilingual when you get hit in the head."
--
Patrick Doyle
Patrick Doyle
I mod down every jackass who puts his moderation policy in his sig. Oh, wait a sec....
Yes.. Unfortunately, slightly short of the miraculous 30 min NY to LA, all of the cargo fell into the ocean. 15 seconds into the flight in fact...
How many G's is this thing expected to pull in accelerating to Mach 7?
Also, wasn't the big problem with anything that is trying to go this fast within the atmosphere friction? They haven't found anything that won't melt at the temperatures that would be generated by speeds that fast. With the exception of missiles or maybe some type of millitary aircraft with consumable heat shields, wouldn't this be silly?
+++ ATH0 +++
OK, I'm sick and tired of people talking about things in which they have NO IDEA!!!!
.4 or below.
if you are going to spew forth something as fact, as least check that it's the truth first.
RAMJET - works best above supersonic speeds, had no compresser (at least not a compresser fan that is). Let's shock waves and natural compression of air as it enters the engine do the compression for it. Internally, all flow is _SUB_sonic. After the air passes through the inlet nozzle, the flow is most of the time slowed down to around mach
SCRAMJET - the SC in the name stands for _SUPERSONIC COMBUSTION_ It is much like the RAMJet except that the internal flow is also supersonic. Not as fast as the surrounding flow, but still above the speed of sound. The actual combustion occurs at supersonic speeds. The problem with these is getting all of the burning of the air and fuel done before it is out of the back of the engine. At Mach 1+ the milliseconds that it takes for fuel to burn completely takes up an awfully large distance. That's why generally, these engines are usual not "jet-fuel" for their fuel. Hydrogen has been suggested because it can burn and react so quickly... I don't recall seeing any large scale working prototypes of this engine yet, but I haven't really looked into it in a few years, so I may be mistaken on this one.
Woops, you're right, I should have sade that most cruise in the .8-.83 range, with some a little faster and some a little slower. My mistake.
Well, yes and no ... yes, the X-15 went faster than MACH 3, but it did so at considerable expense. It had to be carried up to altitude by a B-52. It used a _rocket_ engine, not a jet engine. On the flights where it pushed the speed envolope most, it ended up losing most of it's verticle tail due to heat burning it off.
My understanding on the SR-71 is that its speed is not limited by engine thrust, but rather by heat buildup. If it goes to fast for to long, it would, literally, melt it's wings and control surfaces off, or at least several damage them. As it is, the plane has literally hundreds of parts that have to be replaced every flight do to the heat killing them. It was designed that way.
Actually, Mach is only one of three measurement commonly used for speed of aircraft. There's Mach, indicated airspeed and actual airspeed, all different. Mach and indicated airspeed are used because that's what the aircraft actually feels. As an aircraft approaches mach 1 (civil airliners cruise at .7-.73 generally) there's something called drag divergence. That's why the civil jets fly at the speed they do, much above that and drag starts to seriously go up exponentially almost. mach varies depending on temperature, not density, but temperature.
Indicated airspeed varies depending on density. For most small aircraft, homebuilts or general aviation aircraft that you and I could fly, this is the most important number as it determines when the aircraft will stall or when the wings will rip off. Mostly used at low speeds when air can generally be considered incompressible. If you go faster where you have to start taking into accoutn compression, then you start dealing more with Mach generally.
And finally actual airspeed which is actually a fixed number no matter where you are, at any location, any altitude, any temperature. But unfortunately, this really doesn't matter to much to the airframe or wings, that's why it's least used, except in planning the actual flight path of the aircraft.
Clarify anything?
One SR71 page claims that:
Another site also has references to "mach 3+". Apparently the 'official' claims of mach 3.1 were for security reasons. That speed record was smashed (as I remember it) during one of the SR-71 decomissioning flights (they were decomissioned in the '80s, then recomissioned in the '90s.)Hmm... and a page on the Mig-25 vs the SR-71 notes that (for the Russian MIG-25):
So a Mig-25 was able to get close to an SR-71's cruising speed -- if you were willing to destroy the engine... (this was especially dangerous, since the Mig-25 apparently had no ejection seat).This 'couple of hundred extra MPH' is almost a full MACH (if you compare the cruising speeds of the MIG-25 and the SR-71). Remember, as well, that e=v^2 -- so the 1.25 speed difference is about 1.56 times the heat produced.Over a 1 or 2 hour flight (the endurance record is somethint like 10 hours), that can be a lot of heat to dissapate -- and anything like a radiator is going to mess with your aerodynamics (they apparently painted them black because it helped to radiate heat back out, allowing them to fly about 70 degrees cooler).
If you want an analogy for your derision, consider asking your average olympic athlete to run "a measly 10MPH" faster..... Prepare to get laughed out of the room (or kicked in the teeth, if he's been doing too many steroids).
--
Sometimes boldness is in fashion. Sometimes only the brave will be bold.
New York to Los Angeles in a half hour. Wow.
In completely unrelated news:
Every window from New Jersey to Nevada was broken today, which officials are at a loss to explain. It appears to have been a sharp earthquake which rattled houses and businesses across the country. Seismologists have reported that every one of their seismographs recorded a large spike, possibly a new type of fault slippage previously unknown.
Officials at UnitedSpace were unavailable for comment.
the AC
Hemos is like...sci-fi fans;he thinks technology is cool, but he hasn't bothered to understand the science it's based on
Why is this +5? This guy doesn't know what he's talking about.
The Mach number is defined as M = v / a, where a is the speed of sound. a is defined as:
a^2 = gamma * p / ro
where gamma is the ratio of specific heats
p is the pressure
ro is the density
So, to say the mach number varies greatly with density isn't exactly true.
The difference between scramjets and ramjets is the mach number of the flow in the combustor. A ramjet has approx. 0 mach number in the combustor, and a scramjet has >1 mach (supersonic combustion... SCramjet... get it?)
And your descriptions of super/hyper/etc flows are inaccurate. The definitions are largely based on the shockwave behavior in the intakes (not that flows are "untrue" to each other). That stuff's confusing though, so I'm not gonna try to explain it.
Hope this clears some things up.
--
All glory to the hypno-toad!
As a more direct reason why this won't replace the shuttle, it's still an air-breathing engine. And there's no air to breath where the shuttle goes.
Hey, there are plenty of engineers who *do* get off on those things. The problem is that the people with money get off more on things which go fast and blow up things, thus allowing them to keep other people from getting money.
Well, mine was right; I just failed to define my terms adequately....Here:
V = volume, p = pressure, T = temperature, n = moles of substance, Ru = universal gas constant
p*V = n*Ru*T, as you said.
p*V = m*R*T, m = mass = n*molecular weight of substance, R = gas constant = Ru/molecular weight
p = rho*R*T, rho = density = m/V
p*v = R*T, v = specific volume = 1/rho
So, basically, the same thing. I'm just used to writing it a different way, as it's more useful in fluid dynamics courses.
I'm thinking high altitude balloons dropping rains of ballbearings. Any jet flying into that should tear itself to pieces just using its OWN velocity.
Now that is aikido air defence.
SAAB = Swedish Airplane Always Broken
Sorry, I doubt it. Mach 2 at best for that POS.
X-33 was designed to fail from the beginning. NASA is full of people feeding at the Shuttle trough, they don't want anything upsetting it. Of the three X-33 proposals that they considered they picked the one which everyone outside of NASA considered to be the riskiest, most likely to fail. So now NASA can point at the X-33 and say "See, that SSTO stuff is nonsense."
come on now! This is obviously a smokescreen for the actual mach 55 prototype "Aurora" that the CIA is using right now... somebody call Moulder.
-- Betting on the survival of the media industry is a serious risk. I advise investing elsewhere.
What makes you think it's going to be piloted? Most of these really experimental things are remote-controlled.
"If all goes according to plan, the X-43A should reach a speed of Mach 7, or about 5,000 mph, breaking the record for both air-breathing and rocket-powered airplanes, surpassing even the Mach 6 record set by the rocket-powered X-15 in 1967." They never once mention mach 5 in the article and they even say that the record is mach 6 by a rockey-powered X-15. Read the actual article not just the stupid mistake on /.
i just climb trees, and look for rhythm everywhere.
the existing record for a production [jet] craft is about mach 2.1).
Eh? Hello??? The SR-71 speed is more like Mach 3.0 - SUSTAINED - with many fleet hours at that kind of speed. It was a jet (turbojet).
The X-43A is a RAMjet, which is another kettle of fish.
"Uhm the F-14 TOmcat is listed at 3.5."
Not in any authoritative place; that's for sure. The F-14 actual maximum speed is Mach 2.38.
See: F-14 Specs
a trunk for Spridle and ChimChim, nor any of the cool things like the buzzsaws!
"Hopefully, it will fly at speeds up to almost mach 7 for 10-15 seconds before shutting off and plunging into the Pacific"
Fortunately the seat cushions can be used as a floatation device.
--Brogdon
This tagline is umop apisdn.
We use Mach because when we get above about 450 MPH, the speed of sound becomes the significant point from which to measure your speed. Speed-over-the-ground isn't as important, it's speed-achieved-against-the-aparant-atmosphere that matters; hence if you can do Mach 2.1, you can theoretically do regardless of what the over-the-ground speed is, ie. find a better altitude and go faster.
Sorry, but the SR-71 is a jet powered aircraft that has routinely exceeded Mach 2.1. Even F-15's have exceeded that speed.
As for Mach 5+.... no aircraft that anybody has admitted to has gone that fast.
www.eFax.com are spammers
I used to work with Mary Shafer at NASA Dryden. I don't recall a Mary Shaver.
Mary Shafer is one sharp engineer.
---
Interested in the Colorado Lottery?
Interested in the Colorado Lottery or Powerball games?
check out http://colotto.com
I guess we'll have to wait for the documents to become declassified.
Until then... "Go! Speed Racer! Go-Go! Speed Racer!"
-----
crazy dynamite monkey
Cool! Had to post something for this article.
Why do we use Mach as a measurement of speed when it varies with altitude? No one would ever use a measurement of length that varied with what country you were in? Hmmm... I'll make a measurement called "Schnach" which is 1 meter in Australia, but is 3 inches in the US. Brilliant idea, eh?
You'd know that the other poster is not talking about the SR-71, but is talking about the now-scrapped space-plane project. *plonk*
--
NASA never really does anything unless it is forced to do so in order to avoid embarrassment. In this case, it is most likely the amateur rocketeers at the Australian Space Research Institute Scramjet Project that are forcing NASA to actually do something other than put women, minorities and geriatric white guys on an infrequently flying Shuttle.
Seastead this.
Hypersonic air cargo systems are unlikely to beat reuseable suborbital cargo systems such as those that have been proposed by Bob Truax.
See Idea Futures claim symbol "Sorb" for details.
PS: The same probably applies to passenger transport, despite the high accellerations at the ends of potentially nausea-inducing zero-G travel.
Seastead this.
It's a common engineering error to confuse units -- especially when they are close to each other in standard units.
1000ft/s = 305m/s
1000mi/hr = 447m/s
Seastead this.
damn that's hella fast, i hope they do it. that's like what? NY to LA in 35-40mins? geez.
E.
-
-
This Post has been brought to you by the letter "E".
good call :)
and the SR71 was never a production aircraft ?
Concorde hits Mach 2.1, the Mig 25 (Foxbat) 2.5 and the SR71 Mach 3+
A monkey in every office....
The speed of sound is 764 miles per hour. That makes mach five 3820 miles per hour.
Obviously from the termination of this flight nose down in the Pacific this plane is pilotless. But at 42.6 G constant acceleration, with a flesh pilot, well ... the impact in the Pacific really wouldn't matter, would it? :)))
Get off my virtual lawn, you damned virtual kids!
Therefore Mach 5 == 3300 mph.
At sea level, v = 340 m/s so Mach 5 is 3800mph. The exact relationship is that v = sqrt(\gamma R T) where R is the gas constant, T is the absolute temperature in Kelvin, and \gamma is the specific heat ratio, which is about 1.4 for air.
Unlimited growth == Cancer.
Drop from the B-52
Booster rocket drop and free flight
Unlimited growth == Cancer.
Hmmm... if you actually read the article, you'll see that they're trying to push this plane through Mach 5 to Mach 7. I really don't think the SR-71 flew at Mach 5. There are also no aircraft that fly at Mach 5 without rockets. The X-43A will try to push past records set by air-breathing and rocket-powered aircraft.
The SR-71 didn't use scramjets, which is the principal technology being tested with the X-43A. Maybe next time you should try reading the article and responding with something pertinent.
Why was this modded all the way to 5 when it was such bad disinformation? Pshaw.
Where the wind blows, the tumbleweed goes.
Not to mention the X-15.
I don't quite have the stats, but someone should be easily able to look them up.
"Draw them in with the prospect of gain, take them by confusion." Sun Tzu
That baby will be creating a lot of these. How long before we see experimental aircraft striving for ludicrous speed?!
bah, what does the average user need with 1000fps? the human eye can't discern more than 30 fps. Do we really need all that power just to surf the web, read email, and play windows solitaire? This is just another ploy by the evil chip manufacturers to pump us for more money, when our current boxen will serve fine for years to come!
heh!
It depends on temperature and the medium through which the sound is travelling.
In air at sea level, sound travels around 740mph.
To nitpick _you_ some..
:) The X-15 (rocket plane) went Mach 6 back in the 50-60s. The MiG-25 FoxBat (similar to F15) does mach 2.5+ (probably more like mach 3). The F-15 does mach 2+. The 16 does mach 2+ on a single engine.
:)
:) then it doesn't add up. Pilots wear _spacesuits_. The thing has an operating altitude of 100,000+ feet. Pilots heat their pre-packaged meals by putting the pouch against the cockpit glass. The thing uses special exotic motors and special exotic fuel. (i think its called JP7. Its not flammable. You can apparently fling lit matches into it and they go out. etc etc)
:)
I dont buy for a minute that the SR 71 only goes mach 3. What a bunch of crap
You're telling me the SR-71 only beats these run of the mill jet aircraft by a few hundred miles per hour ?
Bullshit
If you buy the discovery channel folklore about the SR-71 (i do
The plane stretches a significant length during flight from heat expansion. its panels and seams are made to expand so much during flight that it _leaks fuel_ when its cold and on the ground. It takes it _several states_ to make a banked turn when flying over the US.
All this bullshit for a couple hundred extra MPH ?
I dont think so
My opinions are my own, and do not necessarily represent those of my employer.
Bravo.
:)
However, if standard jetfuel is a kerosene derivative, then flinging matches into it is illadvised
My opinions are my own, and do not necessarily represent those of my employer.
Using a booster rocket, the prototype will be accelerated to mach 5, at which point the pilot's face will be torn from his skull. Hopefully, the plane will fly at speeds up to almost mach 7 for 10-15 seconds before getting hit by a Chinese hotdog pilot.
Got Rhinos?
What most people dont realize is that at the speeds were talking about (mach 7-10) you can do a nice suborbital hop. This means you thrust to say mach 8 in the atmosphere on a trajectory that will bring you out of the atmosphere. No air means no mach wave which means no sonic boom (contrary to TV and movies, theres no sound in space) The minimum speed for reaching outer space is a bit more than mach 3. its a simple 1/2v^2=gh calculation. of course, youll come straight back down again if youre going this slow, but you will exit the atmosphere. mach 7-10 allows you to gain altitude and speed along the ground. you wont orbit, but youll go quite a ways. Regardless of this, there is still a market for transatlantic and especially transpacific high speed flights. If, and its a big if, you can keep the costs about the same or a little more than conventional planes. If youve ever had to endure a 10 hour flight across the pacific, im sure youd be willing to pay quite a bit more to do it in 2 hours.
1.) Spy planes. And I mean real spy planes, not the glorified P-3 Orion that the press has been quick to call a "spy plane" recently. :)
2.) Rapid response time. Sure, it may be an engineering problem of figuring out how to shoot at people or drop
bombs on the, but it might be worth it for the 3-4 hour response time to hit just about anybody in the world.
1: The P-3 Orion is a plane. Its mission is to spy on people, which is what it was doing at the time of the accident. How is this not a real "spy plane" Its a plane that spys isnt it?
2: youre right, allegedly people in area 51 have been working on the "45 minutes to anywhere" bomber, who knows if thats accurate.
Wouldn't this be useful as the first stage of a two-stage system?
Hellz yeah!
yet it looks like a duck and quacks like a duck, and has the dna of a duck, but its not a duck, ok.
The frontal area of a scramjet is much higher than the frontal area of a comparably powered chemical rocket. Wave drag is a bitch, and it's the factor that will continue to kill air-breathing high speed flight for the forseeable future. The engine is also much heavier than the oxidizer that a regular rocket would use. Remember, you still need a conventional rocket to get this thing up to the point where it can light up...
What do you mean by "frontal area" are you referring to the leading edge? the leading edge of a scramjet is comparable to that of a rocket. Or do you mean the cross sectional area? if so, then yes, the cross section is higher, but this is needed in order for the engine to work.(it has to take in air) Ultimately the fact that air is flowing thorugh part of the cross section tends to reduce wave drag. Your goal is to get to a point higher in the atmosphere where wave drag isnt as much of a problem. A scramjet engine is essentially a box open at both ends. A very specially shaped box, but a box nonetheless. Oxidizer needs to be held in a tank. a tank is also like a box but closed at both ends. Which is heavier, an empty box open at both ends, or a box full of luquid closed at both ends? If you have a hydrogen powered scramjet, you save 8/9 of the wight simply because in a H-O2 reaction, oxygen wighs 8 times more than the hydrogen. You're right, you do need a conventional rocket to get up to speed, and yes this does cut down on the weight savings, but there is still a significant savings.
more about building strong enough air frames that can properly stretch and continue to act as load carrying structures. The SR-71's wing span stretched by more than a foot at cruising speeds nearing Mach 3. (and yes top speed was 3+)
And how do you store enough fuel? The SR-71 was forced to take off with 1/4 tank of fuel due to weight restrictions. It then had less then 5 minutes to find and hook up with a refueling aircraft, when it would completely top off it's tanks.
Another considerations is the human factor of both pilot skill and physical endurance to manage such a craft. At just Mach 3, a deviance of 1 or 2 degrees from flight plan will put you off course by a mile in about 1 second (literally).
An SR-71 required a minimum of 45 minutes of cool-down time after landing before any anything could be touched or any panels or outlets could be opened.
The SR-71 program discontinued for only one reason. Cost. Go figure.
You can laugh without eating a sandwhich, but you can do both if bring one.
Remember, linus thinks mach sux.
China has only recently developed (well, stolen from us) the rocketry necessary to hit the west coast. Currently, they still can't hit the rest of the US. This is not exactly the same situation as it was with the Soviet Union (and sort of is with Russia). So the scenario is horrendous, but it looks more like Kissingers dream of a 'limited' nuclear war than it does the doctrine of Mutually Assured Destruction. :) This is why the Pentagon wants a missle defense system - it couldn't stop a few thousand Russian ICBMs but it might stop a few Chinese missles.
That was what caught my attention. Now the real question is was that the reporters attempt at trolling to get the attention of everyone? "Oh my God China can kill us faster than we can kill them"(It wouldnt matter we would still have time to blow up the entire world if something ended in nukes) Or was their sort of a space race we did it first type approach? If it is the latter then cool and he should have developed that more. The former he should have been edited. my .02$
I am 31337 or something.
-dB
"It if was easy to do, we'd find someone cheaper than you to do it."
Now, imagine if you will this capability in the hands of 'bad guys'. It makes 100 billion dollars worth of 'star wars' NMD systems in Alaska look pretty stupid, doesn't it? Launch from wherever, take a scenic mach 10 cruise over the mid pacific or the carribean, and 'bang', over the continental city of choice in the mainland US.
You need technology for deterrence, but the only real protection is non-proliferation. That means being cooperative and engaged, not being belligerant and isolationist.
-dB
"It if was easy to do, we'd find someone cheaper than you to do it."
They plan to break mach 5... Thus the LA Times article's title "Plane's Final Destination: Mach 7"
They quote:
"Once detached from the booster rocket, the aircraft will be able to fly between seven and 10 times the speed of sound, or about 4,725 mph to 6,750 mph depending on altitude and atmospheric conditions."
Next time read the fucking article before you make a smart-ass remark.
--Ryan
"And if I could change the future,
Fight or flight its all the same
Live to die another day
--Ryan
"a 12-foot experimental airplane is scheduled to make its maiden flight next month, flying over the Pacific Ocean at more than 5,000 mph."
Nothing like spending billions of dollars on something that can send two midgets across the pacific in record time.
-gerbik
actually the airforce had been quite at home with leaky airplanes for some time at that point.
the common joke about the B-52 among it's crew:
Q: "How do you tell when a B-52 is out of hydralic fluid/gas/oil?"
A: "There's no puddles beneath the aircraft."
So what you're telling me is that with one of these puppies and a parachute I could commute to a job in Silicon Valley from my home in Pennsylvania faster than most of the people who live there? NASA rules.
My other
It seems like every time, that the old speed record has been broken, the SR71 will admit to having already gone that fast. Wonder if it will happen again this time. If you look around, the specs for that plane say something like Mach 3.1+, making its real top speed a classified number.
Logic Bomb, you couldn't have picked a worse name. Going by what you sent into the slashdot crew, it really is a 'Logic Bomb.'
Boy, those crazy engineers. It must have taken some real convincing to sell the military a leaky plane.
Sure, Mach 5 at 5000 mph might be a heck of a feat. But I dare someone to try to break Mach 1 in a vacuum. I dare ya.
Thinner air means less O2, and less O2 means the jet would have it hard to get the amount of fuel needed. Who cares about planes that are too fast to shoot down, what about missile tech.? Doesn't this really just mean that someone can nuke us in an hour, as apposed to 6? an hour? ICBMs take like 15 minutes to fly across the world
Its actually Gripen in swedish.. and there is not a "new" and an "old" one... theres a similar looking older plane called Viggen wich is significally bigger... from what i hear viggens top speed has not been documented but is reported to be somewhere around 2.7M at high altitude... some years ago there was an incident or something involving a blackbird crossing swedish airspace, a viggen managing to keep up and a blackbird crew who were mighty impressed but unfortunatly i remember nothing about this ;)
To achieve this without 1) the plane running out of gas before it hits mach 5 OR 2) the pilot passing out and/or dying due to the number of Gs pulled getting there.
DanH
Cav Pilot's Reference Page
Cav Pilot's Reference Page
UNIX - Not just for Vestal Virgins anymore
Almost. The Concorde at cruise of mach 2.02 (max 2.2) is always on afterburners. What makes the SR-71 and the Concorde different from normal supersonic craft is that they both can cruise with afterburners on, while normal fighters cant, which means both have got supersonic cruise capability. Your normal fighter doesnt as they need after burner and of course, fuel consumption is fierce.
"Old Rallydrivers never die - they just fail to book in on time"
But this doesn't even sound like it's a jet: (I haven't read the article, but just from the post) It's a (SC?)RAMjet, a very interesting tech, potentially allowing relatively normal (read feasible) hypersonic engines, and moreover the fact they seem to want to fly it normally to high speed before switching over is interesting (though unclear: they could just use the raw power of the rocket), but it's not a jet. It's something potentially better, as a turboSCRAMjet (SCRAMjet+turbine-RAM transition ability) would allow normal acceleration to hypersonic speeds in the atmosphere, something potentially useful for next-generation shuttle type things (ie for flying (most of the way) into orbit.) Especially if we could then just seal the front and make a rocket...
He who fights and runs away,
Not to diminish the original intent of the post (exceeding Mach 5 is a significant breakthrough for airbreathing aircraft), but Mach 2.1 is no significant feat.
:-)
Many fighter aircraft can sprint up to <b>2.5 M</b> or better (full afterburners), and <b>Concord</b> can supercruise at <b>2.5 M</b>. The <b>SR-71</b> supercruises at a little over <b>3.0 M</b> with engines which are actually designed to efficiently maintain afterburning during cruise, and the <b>SU-27</b> can reach <b>3.0 M</b>, but the engines have to be replaced afterwards
...to name a few.
"If necessity is the mother of invention, insomnia is the womb."
a=sqrt(gamma*R*T)
At high altitude, the air is very cold, therefore the speed of sound is lower. As you get very high, beyond the stratosphere, the temperature of air increases. However, the air at extremely high altitudes is no longer dense enough to be considered a continuum and the question of speed of sound is moot, since there is none.
Airliners cruise at high altitudes because the lower density and temperature result in lower drag, due to a reduction in the Reynolds number,
Re=rho*V*D/u
"If necessity is the mother of invention, insomnia is the womb."
The F-22 is the first fighter designed to supercruise, but tops out around 1.7 M, with afterburners.
Concord, on the other hand, has been supercruising since the 70's (gives new meaning to superfly:). Concord will apply afterburners at take-off as assurance against any engine-out failures, and afterburns through to about 1.1M to get past the high drag transonic region (as an aircraft approaches the speed of sound, the pressure drag reaches its highest, like a boat catching up with its bow wave prior to planing). After passing through the transonic region, Concord releases the afterburners and continues on to cruise at 2.5M.
"If necessity is the mother of invention, insomnia is the womb."
The story also said that the CIA fed intelligence to the Pentagon that said the 25 was being made from some wildly exotic composite technology and they postulated all kinds of capabilities that required some kind of counter, the F-15 program.
When Belenko drove his Foxbat to Japan and they took a good look at it, they realized it was constructed of much more conventional materials and so the capabilities that the F-15 were designed to counter were non-existant.
---
There is much cruelty in the universe, John.
Yeah, we seem to have the tour map.
see the subject.
---
Although the author seems to be confused about the value of Mach 1, some of the responses aren't much more informed. Mach 1 is the speed of sound, which varies greatly depending on the density of the air. At sea level it is usually around 730 mph or so. So it is difficult to say what Mach number the blackbird achieved when it was flying 2,100 mph. You'd have to know the density altitude for the flight. Also, a scramjet engine is not quite the same as a ramjet. The idea is the same, but since air is highly compressible, it behaves differently at different speeds. There are basically four areas of flow: subsonic, transonic, supersonic, and hypersonic. What holds true for supersonic flow is not necessarily true for hypersonic flow. The divisions between these areas of flow depends on the Mach number of the fluid, which is why speeds are rated in Mach numbers and not mph or km/s. So, a different design is required for hypersonic flow compared to supersonic flow. Hope this clears some things up.
Talk to a soldier or two. Career types are best. They don't want war.
I believe the X15 - a rocket powered plane launched from a B52 - has the inter-atmosphere world speed record for a man-made device - Mach 6.72, or about 5,000 mph at sea level.
"If there's hope, it lies in the proles..."
You're absolutely right. I was merely relating the top speed for an inter-atmospheric man-made device.
"If there's hope, it lies in the proles..."
At sea level, Mach 1 is 760mph. At 40,000 feet it is 660mph. The SR-71 Blackbird has a maximum top speed of Mach 3.54. Her routine altitude is around 250,000 feet. The spacesuits are necessary for the extreme heat, low oxygen, and high stresses of the environment. The skin does expand when she's on the tarmac, due to the expansion of the titanium skin. JP7 is used for it's high flammability point because of this. Considering when the Blackbird was built, I'm amazed they got her to go so far, so high, and so fast.
"If there's hope, it lies in the proles..."
You don't want to drop the bearings, they fall to the ground and you have to pick them up again. They land on your houses, and your buildings, and they land in your lawns, where they become projectiles on Saturdays when you run over them with lawnmowers. You want something like "sky mines". Or invisible high-altitude balloons with large spider webs strung between them.
What is this fool talk'n bout??
(see sig, click sig).
Good quote, too many chars. Seriously, the slashdot 120 char limit sucks!
Everything's fine... except your ideal gas law... where you left out a seemingly meaningless term (at least in this example) ...
pv = nRt, where p = pressure, v = volume, n = number of moles of substance, R = universal constant, t = temperature.
Mooniacs for iOS and Android
. . . unless you only consider NATO countries and you classify the SR-71 as either not a standard jet (being a scramjet) or not production. Since espionage and aerial interception is the hot topic right now, I think it's appropriate to single out the MiG-25. The Soviets built the MiG-25 for one reason: to intercept the US B-70 Valkyrie bomber. This was a four-engine, MACH 3+ bomber that the US never even produced (except some prototypes which I think all crashed during testing). But, the Soviets knew about the project and countered with a MACH 3+ fighter, which became the MiG-25.
(the existing record for a production craft is about mach 2.1). Uhm the F-14 TOmcat is listed at 3.5
Mach 7.1 is stupid fast. To put this in perspective you need an appropriate analogy. If an ant, which normally moves at less the .5 mph were to travel that fast, it would be travelling at 5000 mph. Hope that clarifies things.
Frylock: That's not a toy!
Master Shake: You say that about everything you own. You should own toys. They're fun.
Turn radius approx 90 miles. Not several states. Obviously depends on speed. This is a good average mission distance. They don't turn much at high speeds.
Leaking fuel on the ground. Correct.
Made of titanium for heat and flexibility.
Color indigo blue, not black.
Airspeed as advertised, nothing secretive going on. They are 30+ year old Pratt & Whitney engines.Other than missions, there isn't a whole lot classified about the SR-71. Until brought back in service for the Gulf War, they were all owned by NASA for high altitude experiments.
Sources:
Several trips to Habu hill, Okinawa. Former home of the SR71 fleet.
DoD and NSA clearances (yes they are different) on the Imagery side
Older brother cadet at USAF Academy in Colorado Springs during the 80's.
I have a lot of personal interest in the U2/SR71 (they look cool)
Several years on US imagery dissemination project...much imagery from SR71's used.
Enjoy...
there are no stupid questions, but there are a lot of inquisitive idiots
The main reason wasn't solely turnaround time though, it was inclement weather. Satellites today still can't pentrate cloud cover very well, resulting in a low NIIR's rating. One of the factors in bringing the SR-71 back into service for the gulf war was the fact that we got crappy imagery from our sat's with all the oil field smoke obscuring things. Planes can often fly low enough to help alleviate this. This was considered fairly low risk as we (the coalition) pretty much owned the skies (even in the daytime) over the middle east.
there are no stupid questions, but there are a lot of inquisitive idiots
Have you people already forgotten about the SR-71 Blackbird? The top speed on that aircraft was Mach 3.3.
Pax Vobiscum
You're right. I've heard that such high speeds tear holes in subspace!
Anyway, the SR-71 was able to acheive its remarkable speed not by "scooping enough air and burning it", but rather by taking what little air was availible and compressing it to astronomical proportions... despite the fact the air temp at operating altitude is around -35deg C, the innovative inlets compressed the air to a temperature so hot that the JP-7 (that you can throw a lit match into without it igniting) burned just by being sprayed into it.
---
MacTacToe - for every problem, an elegant solution
Maybe what we need to do is start trying to break underwater speed records and explore the ocean by blowing pieces of it up and analyzing the fragments! How about we repeal the nuclear test ban treaty? That should make things more exciting...We might even end up creating new "species" to replace the ones we're losing. That appeases the environmentalists, and everybody's happy!
Please mod me up. My grandma might not make it to the weekend and she always wanted me to hit karma cap.
Whoa there, cowboy.
Mach 5 is roughly 3800mph at sea level.
But the article gets it right...Mach 7 at several thousand feet is quite close to 5000mph.
Although technically, Mach 5 == 5000mph for compressed (>1atm) air, but you'll be hard pressed (no pun intended) to find enough of that to fly a plane in.
...is what is the projected survivability of this new aircraft in collisions with Chinese interceptor craft?
You see? You see? Your stupid minds! Stupid! Stupid!
If I remember right the record for an aircraft accelerated in level flight was set by the x15 rocket plane at just under MACH 6. It is a rocket plane and the run was so fast that it burned holes in the skin of the aircraft. The heat damage was so great it was not repaired.
Well I was off by one mach it was just under mach 7. That was the flight in with it had to very large fuel tanks and was covered in a special white paint that was to shield it from the heat. It is my understanding it was never flown again because of the damage caused by the heat at that speed.
to outrun Chinese fighter planes?
:)
Could be useful to avoid diplomatic disasters
J:P
--- Worst tagline ever.
Not to be confused with the X-33 and X-34 projects.
... or the X-11
project.
"Never bullshit a bullshitter" All That Jazz
This also made it hard to turn, because you could make one wingtip go supersonic, and have the other one stall.
Shave the Whales!
At the sort of near-space altitudes at which this thing will probably operate, Mach 5 is close to 5000 MPH.
So what speed is the shuttle going just as it leaves our atmosphere? I heard a figure once that it would be the equivalent of Mach 25. Not sure if they meant 25 times 714 or another value taking into account the density of the medium.
Which brings up something interesting up... If the speed of sound is faster in thinner atmospheres, then the speed of sound increases as you approach the threshold of space. However, once in space, the speed of sound should be essentially zero. Sounds confusing.
Where are my moderator points when I need them.:)
But seriously I believe that the equation can be reduced to a function of T . When you figure in the ideal gas law PV=nRT, air density is actually a function of Pressure which also is a function of height, so you can eliminate both height and pressure leaving only function of T.
Could sombody post the actual equation for determining mach?
If someone is passing you on the right, you are an asshole for driving in the wrong lane.
This sucker is damn impressive. The only thing that has come close is the X-15, and that was a rocket with wings, this one uses a rocket to get it up to speed for the engine to take over.
It's not the speed of the aircraft that counts so much, but how it gets upto that speed. People keep trying to compare this sucka to the SR-71, and they're very different.
The air traveling through the SR-71's engine is moving sub-sonic, the moving through the scram-jet is super-sonic. Very big deal.
Mach 3 to mach 5 is also a big deal beacuse other non-linear areodynamic effects take over. That's also a 66% increase. Try and get a 66% increase out of a commercial aircraft traveling at 500 mph. Oh wait we've just gone mach and desintegrated the aircraft.
So stop comparing this to an SR-71, not knocking the SR-71, it's a beautiful feat of engineering. So is the X-43A.
If someone is passing you on the right, you are an asshole for driving in the wrong lane.
Go back and read the article. The idea is to have rockets power the craft to scramjet speed, use the scramjets until oxygen consumption is minimal [probably 100,000 feet, but then I don't have good scramjet data here in my office], and then use rockets again to boost to orbit. So that's their goal in this, although I wonder how they would want to land it, either...
--
-- Geof F. Morris
WHAT THE HELL WAS I THINKING!!!
This will teach me to post five minutes before staff meeting.
a, speed of sound, is a function of three variables:
The actual equation is a=SQRT(kRT).
I knew I should have brought my fluid mechanics text in from the truck this morning. But noooooo, I had to bring in my CD's to rip to MP3 instead. Silly engineer.
--
-- Geof F. Morris
To get mach, after you find a [which, per my reply to this, is a=SQRT(kRT)], is simple:
Ma=V/a, where V is the velocity[*] and a is the speed of sound.
[*] Yes, this could be the airspeed velocity of an unladen swallow, but you know, I don't think a swallow can go supersonic, no matter if it's carrying a coconut by the husk, under the dorsal, or on a line...
--
-- Geof F. Morris
Eh? You've got to get outside the slipstream to make this work. That causes all sorts of perturbations, and crossing the shock--which it will presumably do at some point--will kill a lot of the kinetic energy. Yes, there will be momentum, but we're not looking at that level of v/z combinations, or at least I don't think so.
--
-- Geof F. Morris
Using a rocket all the way is Single Stage To Orbit [SSTO]. Mass fractions there run from 95-99%. Mass fraction, if you don't know, is the fraction of mass that is fuel and oxidizer. That doesn't count engine mass, structure, or payload. SSTO vehicles don't work, because we can't build a vehicle big enough that's reliable and not a budget buster to make it work.
Yes, the oxidizer will weigh that much more. It will make a difference. Not enough of one to make it viable, but a difference nonetheless.
--
-- Geof F. Morris
Miss the part where I said oceanic? Of course, I've got no huge personal problem with the sound of freedom, but hey. =) But the service can be a big business boost. For example, my company does a lot of business with Japanese aerospace companies. Be nice to travel to/from Tokyo more quickly!
Well, not really, as you have to have high velocity to start the scramjet. So that means you have a rocket to start things off to get to scramjet startup speeds, then kick in the scramjet. It might work for a three-stage system, but...
--
-- Geof F. Morris
Coming to that conclusion does suck, doesn't it? I know the feeling--had it last semester. =)
Actually, this really only applies to chemical rockets. You could do SSTO with a nuclear rocket...but then that raises more issues. =)
--
-- Geof F. Morris
Thanks, Decibel, for smacking me upside the head. =)
However, I didn't say the X-43A wouldn't carry its own fuel. I should have said that the X-15 had to carry its own oxidizer. My fault.
--
-- Geof F. Morris
The moveable spike does add a lot of the thrust. But what's being discussed is a scramjet, and as such, it gets all its air without compression. The ramjet is a compromise between the scramjet and the turbojet, really. Also, the ramjet has realistic speed limits, because there is some compression needed to fly, and the craft can't make it to scramjet operational speeds with air-breathing engines.
I'd rant further, but I sold back my propulsion texts when I realized I was going into the church business. Oh well.
--
-- Geof F. Morris
Actually, a [the speed of sound] varies with altitude, as temperature and density have an effect on the speed of sound. You can go supersonic, technically, simply by holding speed but changing altitude.
Most Mach references are to sea level a of 340 m/s.
--
-- Geof F. Morris
Per the article, the X-15 got to Mach 6+.
Yes, the SR-71 got to Mach 3+, but not a whole lot faster--the engines were losing efficiency at that point and couldn't push any harder. Even moving the spike in the aerospike didn't help--you were still using some mechanical compression, and the mechanical compression was what was slowing the flow down. Shutting down the turbine blades wouldn't work, either. The theoretical limit is somewhere in the Mach 3.6+ range. I once saw a better analysis, but that was in a book I sold back. =)
But the "been there, done that..." scenario doesn't hold. The X-15 was a rocket plane, and as such had to carry its own fuel. Also, the X-15 was dropped from a bomber after being carried to altitude. The SR-71 had its theoretical limits as above. This is a step beyond either--something that would take off on its own and fly faster than the X-15. Granted, I don't enjoy aerospace engineering anymore, but even I think this is tres cool.
--
-- Geof F. Morris
This is important aerospace research, and if you read the article, it's pretty easy to see why. The ability to fly at such speeds for intercontinental, oceanic flights is of great societal benefit. Speed of transport will make this work commercially.
The military aspects are a bit more challenging, though. If you're going to build a bomber so fast it can't be shot down, fine--but then you have to either slow down the craft so that the munitions can exit the slipstream, or you have to come up with some design that will allow you to drop iron at high speeds--such as the Valkyrie, which dropped munitions out the tail.
Either is a huge design problem. If you slow the craft down, you have to design a craft that performs at all speed ranges with in-theater fidelity. If you kick the munitions out of the back, you have to compensate for the mass changes with aerodynamics, because you change the center of gravity all the way through the release profile, and you better hold the craft steady during release, lest you hit the bomb on the way out. "Somebody set us up the bomb," indeed!
But this won't replace STS. Yes, a scramjet is nice. Yes, this is similar to rocket-based combined cycle. But we could more cheaply build a reliable, two-stage system to get into orbit. Mass fractions are all you have to look at to wonder why Single Stage To Orbit [SSTO] is some perverted NASA priority. As a NASA sub, I know they don't live in reality, but damn...
But this is, for once, a positive example of your tax dollars at work.
--
-- Geof F. Morris
The speed of sound is approximately 640mph and also varies depending on altitude and atmosphere. The fastest recorded airspeeds by an aircraft was produced using the X-17 prototype that similarly used rocket boosters which took it to around Mach 6.17 I believe. It's a little difficult to be completely accurate considering this was in a magazine that is somewhere in my attic at the moment and about 2 years old. I'm also a little shady on the date, but I think it was in the latter 70s.
I remember when one of our submarines ripped a Japanese fishing boat in two. That was pretty ugly.
Then there was the recent incident involving two helicopters colliding with one another- and that aircraft that cut the support cabling on that gondola in Italy a few years back.
Of course, who can forget the recent collision between one of our spy planes and a small Chinese fighter jet? Ouch.
As an instructor at Ace Driving School, I can say with authority that our men and women in uniform need to learn to drive. Companies like mine can make a huge difference in the number of accidents and monthly insurance premiums. Hey, look at what we did for the fine people at Exxon.
We may get to see a real-life working SCRAMjet engine. THAT's the big wow-factor here, although only aero-nerds will realize that. 1. Standard jets (garden variety aircraft) take in air at speeds mach 1. Then the braking mechanism (part of which was a recovery chute) failed to operate. The final milliseconds of the flight were spent burying deep into the permafrost. (oops) It's good to hear the good ol' USofA is gonna make a run at this. I, for one, would love to see a good tech broadcast on this but I know that all we'll get is some pretty pictures, and a lousy incomplete description like the LA Times story - which really didn't convey the killer science which is behind the experiment.
Is it just my observation, or are there way too many stupid people in the world?
The scientists are not usually the "penis envy" people. It is usually the "little dicks" in politics that have the money that want the bigger, faster, stronger technology.
Good post. Thank you, I like seeing a smart post.
Will this plane still get run into by the chinese at those speeds?
JP7. Its not flammable. Pretty much. They use unsymmetrical Dimetheylhydrazine to light it off. The exotic motors are hybrid turbo/ramjets by GE. Urban legend in the USAF has it that the SR-71 is Mach 4+
meh.
are here
m l
http://lisar.larc.nasa.gov/LISAR/BROWSE/hyperx.ht
pretty cool.
I was stationed at an air base in Florida that I will leave unnamed. Anyways early in the morning (4am) you could some times hear a succession of sonic booms 5 or 6 in a row coming from off the Gulf of Mexico. Now you can say the sonic booms could have been anything, but there was a popular rumor of a top-secret super fast fighter (possible unmanned) being tested on the base at that time. Put the 2 together and it makes you think?
Mach 5 is the speed that the scramjet needs to kick in. When this happens, the plane will theoretically accelerate to Mach 7. It says right there in the article that the current record is Mach 6, set in 1967, not Mach 2.1, which is only about 1500 mph, depending.
The speed of sound varies proportionally with temperature, not density! The speed of sound varies proportionally with pressure and _inversely_ proportional with density through the ideal gas law (pressure/density is proportional to temperature.)
The speed of sound (and temperature) decrease with altitude until you reach about 100000 feet (30 km.) At sea level the speed of sound is about 340 m/s. At the operating altitude of this aircraft of 100000 feet the speed of sound is only 295 m/s.
Mach 7.0 @ 100000 feet is equivalent to about 7434 km/h or 4619 mph.
Above ~40 km the speed of sound (and temperature) increases although both pressure and density continue to decrease, until you reach an altitude of about 70km where the speed of sound (and temperature) begins to decrease again. Pressure and density decrease with altitude, but not at the same rates, thus temperature decreases, then increases, then decreases again.
...is located here
SIG: TAKE OFF EVERY 'CAPTAIN'!!
/* This post not warrantied for mission critical applications. */
Er... Well, y'know. You can't make an omelette without um... destroying a forest. Or something.
My only political goal is to see to it that no political party achieves its goals.
I think the keyword here is "production". Only 32 SR-71s were ever made, which makes it a custom job compared to the F-15. Still, the MiG-25 "Foxbat" was no slouch either, with reported figures of Mach 2.8 (sustained) and 3.1 (peak), with The Mig-31 "Foxhound" claiming better figures.
(this is not a
Who told you that Mach 5 was 5000 mph !!! ? .
... !
Conventionally, the speed of sound used for this kind of comparison is ~340 m/s (sea level, normal pressure and temperature)
This makes something like 3800 mph !
And the value Mach 1 is implicitly expressed under these conditions!
Useless
The Air Force has been experimenting, and probably using GPS guided munitions. Assuming a higher altitude for this type of aircraft it is very plausible it would not even have to enter enemy airspace to hit its target.
Guided bombs using GPS would have both velocity and altitude that they need to make course corrections on the way to target. It is not very dissimilar from guiding a mirv.
* Winners compare their achievements to their goals, losers compare theirs to that of others.
I was under the impression that the fastest atmospheric flight was Mach 4.3. At least that's what I remember reading in Guinness... And lest anyone get confused, that speed was nowhere near 4300MPH. The speed of sound is considerably lower (see the diatribe and resulting corrections two or three strings below...)
Sorry, not just under mach 6, it was actually more like mach 6.2 on some of its faster flights. It is also one of two winged vehicles which has been flown in space. Eight pilots of the X-15 managed to get their astronauts wings in it, including Joe Engle, prodigy child of Chuck Yeager. Engle took the X-15 to mach 5.71 (3,886mph). I have never heard of any such heat damage, and I know the X-15 was flown many times. The shuttle has flown Mach 25 in the atmosphere, also by Engle. He manually flew the entire re-entry, performing 29 flight test maneuvers.
Sorry, let me correct my numbers... The X-15's fastest flight was Mach 6.7 (4,520 mph), not Mach 6.2 as I said in my earlier post. It reached a maximum altitude of 354,200 feet. There were 3 X-15s made, and of those, 2 are in museums. The other crashed, and parts of it are in 2 separate museums.
Also, of course, not to be confused with the X10, which is a whole different kind of fun altogether. :D.
=-=-=-=-=
=-=-=-=-=-=-=-=-=
Oh bother.
A real good trick would be mach 2 aircraft at 100 ft of altitude, the shock wave would be devestating, bombs, who needs stinking bombs when your, mach 2 at 100 ft!
Apocalypse Cancelled, Sorry, No Ticket Refunds
The speed of sound is about 765 MPH. In 1967 it reached Mach 6.72 (7,297 kilometers or 4,534 miles per hour).
Here is the cool link where you can read about our progression in the 50's and 60's:
http://www.x15.com/program.html I don't know why this rocketship wasn't publicized very much but It's the first thing that I look at when I visit the Smithsonian Air and Space Museum in DC.
Logic Bomb writes: "Mach 5 -- 5 times the speed of sound, or 5000 mph -- is a speed that so far has eluded jet-powered aircraft (the existing record for a production craft is about mach 2.1).
Umm, while the Blackbird (SR-71)'s top speed is classified, most knowledgeable folk put it between Mach 3.1 and Mach 3.3.
Also, there are always those fun tales off liquid hydrogen tanks at Lockheed, and C5's loading strnagely shaped waveriders.
the SR-71 was announced by LBJ, was flying in the 70's, and is not hypersonic.
textbooks.
Ie., given a certain inlet spike geometry, figure out the greatest Mach number that will keep the mach cone from infringing on the inlet.
The F-104 (also by Lockheed) had a nifty convex inlet curve to allow lots of little compression shocks.
But this is all probably over your head.
Don't count on flying from Dallas to Tokyo on this thing any time soon. Who could stand the acceleration involved better a human or a missile payload? Simply, if the test works, it's almost ready to go as a cruise missile, but years away from arrying any passengers.
Could you please explain why the speed of sound in a bar of steel or a basin of water is faster than the speed of sound in air, even if they are all at the same temperature, if the speed of sound only depends on temperature? I'm not an expert on this subject by any means, but the last I heard, the speed of sound depends on the density and the elasticity of the medium.
Taking stuff apart since 1969 (TM)
Solids, like liquids, are classified as "noncompressible." Gases are compressible. If the medium is noncompressible, how can it support compression waves? I believe it can't (in most ordinary circumstances); the railroad track supports vibrations, but not compression waves.
Taking stuff apart since 1969 (TM)
Last time I watched a Nova special on supersonic jetfighter pilots, I distinctly recall a long segment on overcoming the tendency of the high g-forces of supersonic travel making people, well, pass out. Is this really a viable technology for commercial travel? I assume that the G's are a factor of how fast you accelerate, not how fast you actually end up going (my physics is a little rusty so don't laugh if I have this all wrong) but how realistic to think that you're going to be able to get up to these never-before-experienced speeds on a nice, slow even burn? Anyone got expertise?
It Is the Nature of Information to Transgress Artificial Boundaries
http://www.majestic-alliance.com/downloads/x43_1.m ov
2 .m ov
http://www.majestic-alliance.com/downloads/x43_
That's fast enough to make Speed Racer jealous!
But seriously, don't aircraft going at those speeds do more environmental damage? I think I heard something about that in high school....
-Henry
"Useless organic meatbag" -HK-47
Does this hold hope for SSTO development? Single Stage to Orbit is the next step from here....
14 miles in 10 seconds, from a dead stop, assuming constant acceleration = 46.2Gs. Damn.
What about the Space Shuttle? That thing re-enters the atmosphere at Mach 20-something.
> Freedom is Slavery! Ignorance is Strength! Monopolies offer Choice!
Of course monopolies don't offer choice. That's why socialism and communism are evil.
I am for the complete Trantorization of Earth.
anyone ever hear of the lockheed sr-71 "blackbird" spy plane? production numbers are listed at mach 2.8+ but tests have shown it flying as fast as mach 3.3.. in a test in i believe the early 90's before the birds were to retire one was flown coast to coast in under 60 minutes...
Close but not quite correct, the ideal gas laws are only held true for a theoretical "ideal" gas, i.e. it doesn't exist but the relationship does hold to a certain extend. Although the equations only hold for a fixed or know volume: PV=nRT How does this relate to the speed of sound? Well the speed of sound in any material is relational to the abilitiy of the material to conduct compression waves. For example in the cowboy movies the hero puts his ear to the train trak to hear the approaching train, why? because the steel is denser and a better conductor of compression waves than the surrounding air, therefore you can hear the train when you press your ear to the track yet no hear it normally. In aviation terms speed is generally measured on two scales: ground speed and apparent air speed. Gorund speed is the amount of "ground" being cover and is constant with altitude when the velocity of the vehicle is constant. Apparent air speed is the speed of the aircraft relative to the air immediately outside the vehicle.
Surprisingly, most of the JP series has low flammability.. I don't recollect the numbers, but the black, the pink and the blue are 'match safe', and the yellow and a couple of the are not.
Oh, yeah. the colors. Airplane fuel is coloured to indicate grade so that you can take a small sample from the wingtanks and tell by looking at it if you've got the right sort of fuel for your bird.
Here has a quick blurb about why and other neat stuff about fuel. I couldnt' find a comprehensive fuel colour list, but I didn't look that hard.
Brant
Brant
Argle. Bargle.
i think its called JP7. Its not flammable. You can apparently fling lit matches into it and they go out.
To further carry the nitpick train...
The fact that JP7 does not burn when matches are flung into it does not make it exotic. You can do the same thing with diesel.
Brant
Brant
Argle. Bargle.
Speed Racer realizes the misrepresentation of "the" Mach 5.
Nasa wasting money. Thank god I British.
Shoot me
I've set my filter to +2, so someone else besides me could have corrected this already.
If you don't look up, you'll never know what's there.
the mach number is a constant that compressable flow is dependant upon.
you need to complain to god or something. at speeds close to the speed of sound in that medium, the mach number is a very important number. it can be used to very easily characterize the way that the medium will flow around an object.
in aircraft design, an optimum airfoil and engine geometry is characterized by the mach number.
one other technical thing. the mach number is not a unit. that is like saying the number 1 is a unit. the mach number has no units. that is why it is so convenient for engineering. it doesn't matter whether you use metric or imperial.
i can't decide whether you are trolling or just plain stupid, so i'm posting.
Bored with your projects?
Try Einsteinium
Either it's deisgned to operate without a pilot, or the plan has the untimely death of the pilot factored in, since the vehicle will "plunge into the pacific" to end its flight...
Too bad engineers don't get the same woody from trying to do something truly challenging like exploring the ocean, building oceanic habitats, or finding ways to use renewable resources more efficently.
Or (heaven forbid), they find alternative fuels.
Mach 5 ~ 3750mph.
5000mph ~ 6.66 mach
Casual Games/Downloads
If nasa wants Mach 5, why don't they just ask Speed Racer? He already has one.
Disconnect your television. Do your own research. Draw your own conclusions. They're probably lying. Don't be a sheep.
"Using a booster rocket, the prototype will be accelerated to mach 5, at which point" ...it's pilot will be ripped to shreds.
--
--
silence is poetry.
What is the point in building a plane that travels so fast that it's only means of stopping itself is to plunge into the ocean?
--
--
silence is poetry.
Admittedly off-topic, but...
Am I the only one who remembers when the Mach 3 razor was just a joke on Saturday Night Live?
"We at Gillette want our products to be cutting edge," Kilts said, "Absolutely at the bleeding edge of technology."
The product name has yet to be announced, but Kilts claims, "They will have 5 or more blades."
--
... but seriously, what is the point of all of this? Don't feed me that baloney about technology, spacemen and iron heros. The Cold War is over, folks. Let's turn our attention to the real issues at hand: I can't name any right now. This is my worst troll ever. I'm sorry.
"If the Lord had meant for us to fly, He'd have given us wings with which to soar...." William, 14:35