Slashdot Mirror

If you ever have the chance, you should go see it in person. Pictures don't seem to do justice for the elegance and majesty of this black metal sculpture that once flew.

You're probably thinking of the two SR-71B trainer aircraft which had an extra cockpit added above and behind the SRO position. The SR-71A, the standard model, had one cockpit - with two seats. One seat for the pilot and one for the RSO (reconnaissance system officer). You can see the RSO's window in this photo:
http://www.sr-71.org/photogall...

Here's a video of a SR-71 pilot showing the two positions and talking about the roles of the pilot and the RSO.
https://www.youtube.com/watch?...

Interestingly, neither person can fly and land the plane by themselves. The RSO did the navigation, telling the plane where to go (auto navigation to specified points is required at mach 3), while the pilot controlled altitude, rudders for landing, etc. If either the pilot or the RSO became incapacitated or the intercom was lost, they would have to bail out.

Will it still leak oil straight off the showroom floor like a '57 Jaguar?

Or, more relevantly, will it leak fuel straight off the assembly line floor like its predecessor?

At rest on the ground, fuel leaks out constantly, since the tanks in the fuselage and wings only seal at operating temperatures. There is little danger of fire since the [SR-71's special] JP-7 fuel is very stable with an extremely high flash point.

http://www.sr-71.org/blackbird/sr-71/

Back when I was living in Wichita, Kansas, one of the few nice things about the area was the Cosmosphere, a shockingly out of place top-notch aerospace museum in nearby retirement town Hutchinson. It has a decommissioned SR-71 hanging from the ceiling in the lobby. I'm not by any means an aircraft geek, but even I have to stop and mumble "that is a gorgeous plane".

Oh, I've done my homework. Question is, have you?

XB-70 was a prototype, they built two of them in total. They broke Mach 3 a grand total of ten times.
MiG-25, as I said, doesn't count. It could only theoretically handle Mach 3.
X-15 is a rocket, not a plane. It needed to be air-launched from a B-52.

Face it, there were never "lots of planes" that could do Mach 3+. There really ever was the SR-71.

As for your "theories" about the SR-71's top speed I can only say that you're wrong. The flight manual of the SR-71 has been declassified for quite a while now; I suggest you go read it: http://www.sr-71.org/blackbird/manual/.

Finally, a word or two on the MiG-25 and friction heating. The MiG-25 was built out of nickel-steel alloy because the soviets couldn't afford/couldn't work well with titanium. As you observed yourself, nickel alloys were also used on the X-15 to protect it from friction heat. So your claim that the MiG-25 was "capable of 3.2 without anything unusual" is bogus. It was built from 80% nickel steel alloy, if they had been able to afford it or work with it, it would have been built out of titanium like the SR-71.

The flight manual is online at sr-71.org

Top speed is well known: 2,193.167 mph, achieved in 1976. Most of the speed runs came in between 2100 and 2200 mph. The most impressive one is from 1990, with an average speed of 2124.5 mph over 2086 miles. That's the truly impressive number. Rocketing to Mach 3 for a brief period has been done by various experimental aircraft, but coast to coast at that speed, only the SR-71 could do in atmosphere.

An actual M-21 aircraft, the SR-71 with the Tagboard drone option, is at the Museum of Flight at Boeing Field in Seattle. They have the maintenance documentation for it, and if you're interested you can make arrangements to see it. Some has been scanned and is on the Web.

OK, found the links. The chart of CIT-limited speed versus outside temperature is at http://www.sr-71.org/blackbird/manual/5/5-10.php. There are envelope curves at http://www.sr-71.org/blackbird/manual/5/5-9.php which you could imagine extrapolating past the limits in the manual.

OK, found the links. The chart of CIT-limited speed versus outside temperature is at http://www.sr-71.org/blackbird/manual/5/5-10.php. There are envelope curves at http://www.sr-71.org/blackbird/manual/5/5-9.php which you could imagine extrapolating past the limits in the manual.

that was the YF-2, a weaponized version of the SR-71. Really, it was a fighter/interceptor, not a bomber.

I used to have a conceptual art poster of it from Lockheed.

What is aYF2? Do you mean the SR-71 forerunner, YF-12A ? The SR was never weapon-ized. It did, however, carry an . unmanned reconnaissance vehicle.
The initial flight dynamics testing was performed in the 10 x 10 SWTat NASA Lewis Research Center in Cleveland, Ohio back in the mid 50's. One note that is not really explained is that it has no top end, only operational limits. This is still the fastest non-orbital craft ever. It will continue to increase its speed to engine failure.

SR-71 Blackbird, service ceiling of 85kft:

http://www.sr-71.org/blackbird/sr-71/

It did not leak like a sieve. A sieve is a device that would leak continuously as it is a filtering apparatus.

It did leak continuously, until heat caused it to cease to be like a sieve.

The sr-71 did not really have fuel tanks the whole plane was the fuel tank and yes the skin did leak at the edges

Yes the skin and (other structural components) acted as the fuel tank and was heated by friction. They're still called fuel tanks just like JP7 is still called jet fuel.

You are perpetuating an urban myth.

As is every museum, documentary, books written by former pilots and maintenance crew...

but the leaks were not the amounts you seem to be indicating.

Sure, I see that I suggested leaking fuel contributed to the operational costs, and that's probably not true at all. I've seen pictures that show plenty of fuel leaking out, though obviously a tiny fraction of what's going through the engines. The plane was plenty expensive to operate without needing to throw in that it leaked fuel like a sieve as a factor. But, well, it did. :)

Does anyone on /. honest believe anything seriously juicy or even particularly interesting would *ever* be released to the public.

Cool stuff gets declassified all the time. The Los Alamos Primer was a pretty awesome read, and it was declassified in 1965 - only 20 years after the bomb was invented.

If you'd like something more recent, how about the SR-71 Blackbird Flight Manual?

Nah, I had just shot those and tried to make a photosynth of them. It didn't act as advertised, but at least all the photos ended up online. I didn't have them anywhere else to link to, or else I would have linked directly to the cockpit photo, which shows two distinct cockpit windows.

    How about this...

    USAF Diagrams of the pilot and RSO seats

    Photo of the RSO seat (the rear seat)

    It's not to argue the point though. There were 13 1-seat A-12 and 32 2-seat SR71's built.

    And just to keep things interesting. Here's a M-21 with a D-21 drone

Nah, I had just shot those and tried to make a photosynth of them. It didn't act as advertised, but at least all the photos ended up online. I didn't have them anywhere else to link to, or else I would have linked directly to the cockpit photo, which shows two distinct cockpit windows.

    How about this...

    USAF Diagrams of the pilot and RSO seats

    Photo of the RSO seat (the rear seat)

    It's not to argue the point though. There were 13 1-seat A-12 and 32 2-seat SR71's built.

    And just to keep things interesting. Here's a M-21 with a D-21 drone

The big danger of going too fast was the compressor inlet temperature (CIT). That, more than anything else, was the limiting factor for speed.

For the SR-71, Mach 3.3 was the maximum allowable ("when authorized by the Commander"), providing CIT does not exceed 427 degrees C. Could probably go faster if you were willing to start melting things in the engines.

Also, the JT11 engine was not a ramjet, it was a bleed-bypass turbojet. The turbine was always spinning and burning some fuel, after Mach 2.0 or so the inlet guide vanes and the internal bleed air bypass system diverted some HP air around the core into the afterburner.

Check out http://www.sr-71.org for some amazing reading.

SR-71
http://www.sr-71.org/blackbird/sr-71/

JP-7 has a high flashpoint (60 C). A Caesium compound in the fuel helped disguise the radar signature of the exhaust plume. Other additives are mentioned here:

http://en.wikipedia.org/wiki/JP-7

"The very low volatility and relative unwillingness of JP-7 to be ignited required triethylborane (TEB) to be injected into the engine in order to light it up, and to light up the afterburner in flight."

Here's the Pilot's Operating Handbook for the SR-71: http://www.sr-71.org/blackbird/manual/

It's a very cool read.

The SR-71 is powered by turbojets. There is some clever ducting that will bypass airflow past the engine at high speed, but the actual engines are in fact turbine engines with blades that go spinny spin and everything.

This is a great set of images of what is happening inside the nacelles at various speeds: http://www.sr-71.org/blackbird/manual/1/1-33.php

Actually the SR-71 and the YF-12 flight manuals have been declassified and are available online.

For the SR-71A, "Mach 3.2 is the maximum design Mach number. Mach 3.17 is the maximum scheduled cruise speed recommended for normal operations. However, when authorized by the Commander, speeds of up to Mach 3.3 may be flown if the limit CIT of 427 degrees C is not exceeded." (CIT is the compressor inlet temperature and was a critical limiting factor in maximum speed)

From Mach 2.6 to Mach 3.2 the SR-71 is limited to -0.1 to +1.5g maneuvering.

Source: http://www.sr-71.org/blackbird/manual/5/5-8.php

Which is an amazing read, tons of details.

I though the same thing for years. However it appears that the POH for the Blackbird has become public record. This manual basically describes how to fly the plane. The manual is now online @ http://www.sr-71.org/blackbird/

The manual clearly shows that the planes design speed is mach 3.2 - exceeding this speed requires authorization from command.
The thing that not everyone realizes is that unlike other planes that can go mach 2 or 3, they cannot sustain this speed due to excessive heating and or fuel consumption constraints. The blackbird is different in that it is designed to fly for ~ 3 hours at these speeds. In fact there are several guages dedicated to external heating for the plane. http://www.sr-71.org/blackbird/manual/5/5-9.php

So with all that said, the flat out top speed may be higher, but the operating manual usually wins out.

The summary for the article is mostly incorrect regarding the blackbird. The engine design of the blackbird is a hybrid design. The engine is a turbojet but there is a ramjet bypass for higher speeds. Ramjets are also known to work at speeds of up to Mach 5+. Though the scramjet engine is not much different it's just that the characteristics of the shockwaves change so much that the shape of the engine needs to change to achieve the same effect. So the limitation is not its engines, it mostly has to do with heating of the aircraft surfaces. Of the many topics discussed in the manual for the blackbird, external and internal heating was a major area of attention.

So if the Blackbird has issues with heating - you can bet that any other plane operating at that speed or higher will have the same problem. Unfortunately it is difficult to find a place to dump the excess heat. Any surface that comes into contact with the airstream causes friction, and heat buildup. You can use the fuel as a coolant, and the blackbird did. The JP-7 fuel that the blackbird used had an extremely high flashpoint. So it could be used to absorb some of the internal heat before being burned off. The blackbird is also much more like today's aircraft in construction - it was one of the first aircraft to use titanium alloys extensively in its construction.

The bottom line is that you don't just build a scram jet powered plane. It's not just about the engine, but about the entire plane. The challenges run the entire range from thermal to mechanical. To simply throw out a number like mach 15 and think that it's feasible to obtain any lasting operation at that speed using today's technology shows a distinct lack of understanding of the subject matter.

I though the same thing for years. However it appears that the POH for the Blackbird has become public record. This manual basically describes how to fly the plane. The manual is now online @ http://www.sr-71.org/blackbird/

The manual clearly shows that the planes design speed is mach 3.2 - exceeding this speed requires authorization from command.
The thing that not everyone realizes is that unlike other planes that can go mach 2 or 3, they cannot sustain this speed due to excessive heating and or fuel consumption constraints. The blackbird is different in that it is designed to fly for ~ 3 hours at these speeds. In fact there are several guages dedicated to external heating for the plane. http://www.sr-71.org/blackbird/manual/5/5-9.php

So with all that said, the flat out top speed may be higher, but the operating manual usually wins out.

The summary for the article is mostly incorrect regarding the blackbird. The engine design of the blackbird is a hybrid design. The engine is a turbojet but there is a ramjet bypass for higher speeds. Ramjets are also known to work at speeds of up to Mach 5+. Though the scramjet engine is not much different it's just that the characteristics of the shockwaves change so much that the shape of the engine needs to change to achieve the same effect. So the limitation is not its engines, it mostly has to do with heating of the aircraft surfaces. Of the many topics discussed in the manual for the blackbird, external and internal heating was a major area of attention.

So if the Blackbird has issues with heating - you can bet that any other plane operating at that speed or higher will have the same problem. Unfortunately it is difficult to find a place to dump the excess heat. Any surface that comes into contact with the airstream causes friction, and heat buildup. You can use the fuel as a coolant, and the blackbird did. The JP-7 fuel that the blackbird used had an extremely high flashpoint. So it could be used to absorb some of the internal heat before being burned off. The blackbird is also much more like today's aircraft in construction - it was one of the first aircraft to use titanium alloys extensively in its construction.

The bottom line is that you don't just build a scram jet powered plane. It's not just about the engine, but about the entire plane. The challenges run the entire range from thermal to mechanical. To simply throw out a number like mach 15 and think that it's feasible to obtain any lasting operation at that speed using today's technology shows a distinct lack of understanding of the subject matter.

According to most of the sites I've seen, A-12 60-6933 racked up 217 flights, and 406.3 flight hours.

http://www.sr-71.org/

A-12 60-6933 flew 217 flights for a total of 406.3 flight hours.

http://www.sr-71.org/blackbird/flighthours.php

Area 51 is real and is used everyday. There are planes that take off everyday from McCarran Airport in Las Vegas bringing employees to Groom Lake.

"Another area of interest is the EG&G terminal on the Northwest corner of McCarran International Airport. Every weekday morning, about 500 people arrive at the guarded terminal with one destination, Groom Lake. When I was in Las Vegas observing the activity of the EG&G terminal, I counted six EG&G owned 737-200s. The aircraft are easily identifiable; they are white with a red strip running the total length of the plane. They fly out to Groom Lake about every half hour in the morning but things slow down in the afternoon with about two to three aircraft always sitting outside. Starting in the late afternoon (I noticed one coming in at 2:30 PM), the 737s start coming back to Las Vegas. At about 6:00, all of the aircraft (6 of which I counted, there could be more) were back to the EG&G facility for the night. Below are the photos that I took when I was out to Groom Lake and observing the EG&G terminal." From sr-71.org, and a picture here.

Also for the "new" Area 51, Popular Mechanics had an article a long time ago that is located here.

Area 51 is real and is used everyday. There are planes that take off everyday from McCarran Airport in Las Vegas bringing employees to Groom Lake.

"Another area of interest is the EG&G terminal on the Northwest corner of McCarran International Airport. Every weekday morning, about 500 people arrive at the guarded terminal with one destination, Groom Lake. When I was in Las Vegas observing the activity of the EG&G terminal, I counted six EG&G owned 737-200s. The aircraft are easily identifiable; they are white with a red strip running the total length of the plane. They fly out to Groom Lake about every half hour in the morning but things slow down in the afternoon with about two to three aircraft always sitting outside. Starting in the late afternoon (I noticed one coming in at 2:30 PM), the 737s start coming back to Las Vegas. At about 6:00, all of the aircraft (6 of which I counted, there could be more) were back to the EG&G facility for the night. Below are the photos that I took when I was out to Groom Lake and observing the EG&G terminal." From sr-71.org, and a picture here.

Also for the "new" Area 51, Popular Mechanics had an article a long time ago that is located here.

YOu may be thinking of the SR-71, which was around for maybe 25 years before they started talking about it in public.

Such rapid transport is most useful for large distances and usually covers large bodies of water (ie. distances you couldn't or wouldn't ride a horse). The generation or two before the average slahsdotter saw the first automobiles; a couple generations before that saw the rise of the steam engine. Before steam power, transportation had remained largly unchanged since the evolution of sail millenia ago. In about 3 centuries we've gone from days, even weeks, to cross the Atlantic to a record of 108.273 minutes.
The average trans-Atlantic trip via Concorde was 3.5 and probably will remain the fastest publicly available trasport record for some time to come; but we may be aproaching the day when flying from Los Angles to Tokyo could be faster by traveling East just to have enough time to comfortably get up to speed/elevation and slow down again.

Aren't you stereotyping old people as being not tech savvy?

I try not to respond to ACs as they will never see it, but.

Well, yes and no.

Most 70 year old people are not tech savvy, most not all. Of the ones that are, there are probably even less that know how to rip VHS to mpeg and out of those there are probably less that would and then share it online.

Out of my 2 sets of grandparents, one thinks that digital is a synonym for expensive, they do not own a computer. The other worked on the SR-71 so it's a safe bet he has a technical mindset ;-), also does not own a computer.

I'm in no way labeling old people as technically inept, but most folks don't expect the person that leaked the video to be 70 years old, 20 sure.

Or at least so says this page on "Cockpit Pressurization Schedules" from the flight manual...gotta love FOIA.

I just checked, it just says over mach 3.0... clearly it's the fastest over long distances.

Not so much any more. The operating manual limits it to mach 3.2; you should download it and check it out. So far as I know, the highest measured speed of the SR-71 is below that of the Mig-25 foxbat; but the two are very close.

Of course, the SR-71 can cruise at mach 3, so over long distance it easily trounces the Mig, but over short distances it seems that the Mig just edges it; by a precious few miles per hour. I think that Guinness didn't know which one was faster, but I'm not aware of any evidence that the SR-71 was actually faster. There are plenty of rumours of course...

• E-266 (i.e. Mig-25 with bigger engines): 2605.10 km/h (1618.73 mph)
  
• SR-71: 3367.22 km/h (2092.29 mph)

I just checked, it just says over mach 3.0... clearly it's the fastest over long distances.

Not so much any more. The operating manual limits it to mach 3.2; you should download it and check it out. So far as I know, the highest measured speed of the SR-71 is below that of the Mig-25 foxbat; but the two are very close.

Of course, the SR-71 can cruise at mach 3, so over long distance it easily trounces the Mig, but over short distances it seems that the Mig just edges it; by a precious few miles per hour. I think that Guinness didn't know which one was faster, but I'm not aware of any evidence that the SR-71 was actually faster. There are plenty of rumours of course...

• E-266 (i.e. Mig-25 with bigger engines): 2605.10 km/h (1618.73 mph)
  
• SR-71: 3367.22 km/h (2092.29 mph)

I just checked, it just says over mach 3.0... clearly it's the fastest over long distances.

Not so much any more. The operating manual limits it to mach 3.2; you should download it and check it out. So far as I know, the highest measured speed of the SR-71 is below that of the Mig-25 foxbat; but the two are very close.

Of course, the SR-71 can cruise at mach 3, so over long distance it easily trounces the Mig, but over short distances it seems that the Mig just edges it; by a precious few miles per hour. I think that Guinness didn't know which one was faster, but I'm not aware of any evidence that the SR-71 was actually faster. There are plenty of rumours of course...

• E-266 (i.e. Mig-25 with bigger engines): 2605.10 km/h (1618.73 mph)
  
• SR-71: 3367.22 km/h (2092.29 mph)

I just checked, it just says over mach 3.0... clearly it's the fastest over long distances.

Not so much any more. The operating manual limits it to mach 3.2; you should download it and check it out. So far as I know, the highest measured speed of the SR-71 is below that of the Mig-25 foxbat; but the two are very close.

Of course, the SR-71 can cruise at mach 3, so over long distance it easily trounces the Mig, but over short distances it seems that the Mig just edges it; by a precious few miles per hour. I think that Guinness didn't know which one was faster, but I'm not aware of any evidence that the SR-71 was actually faster. There are plenty of rumours of course...

• E-266 (i.e. Mig-25 with bigger engines): 2605.10 km/h (1618.73 mph)
  
• SR-71: 3367.22 km/h (2092.29 mph)

I just checked, it just says over mach 3.0... clearly it's the fastest over long distances.

Not so much any more. The operating manual limits it to mach 3.2; you should download it and check it out. So far as I know, the highest measured speed of the SR-71 is below that of the Mig-25 foxbat; but the two are very close.

Of course, the SR-71 can cruise at mach 3, so over long distance it easily trounces the Mig, but over short distances it seems that the Mig just edges it; by a precious few miles per hour. I think that Guinness didn't know which one was faster, but I'm not aware of any evidence that the SR-71 was actually faster. There are plenty of rumours of course...

• E-266 (i.e. Mig-25 with bigger engines): 2605.10 km/h (1618.73 mph)
  
• SR-71: 3367.22 km/h (2092.29 mph)

They also had an SR-71, and I think it's predecessor, which I can't remember the name of (there are only like 3 in existence).
The YF-12A?

Several people have suggested that there are many aircraft (miltary and civilian) that rival the Concordes ability to fly at a sustained mach 2 for several hours. However, according to this site www.sr-71.org it is only Concorde and the SR-71 which can do this. I know there are aircraft faster, more efficient etc thats not the point. This is still beyond the performance of all civillian aircraft and virtual all military aircraft. Further, a sustained high speed must be a most desirable characteristic of any passenger aircraft. (It does not take Concorde 2 hours to reach this speed either concordesst). Bottom line, we want aircraft to get us there quick, and concorde is the quickest.

My tour would be to see all of the publically displayed SR-71s.

My Dad experienced this first hand when he was in the airforce. He saw something on radar (he was working in radar at the time) that was moving too fast. Later he surmised that it was a Blackbird (although it was long enough ago it could have been an Archangel or other classified high speed military plane). None of this was explained to him at the time and it was literally a UFO (Unidentified Flying Object). The Blackbird wasn't declassified until many years later. That was when he put two and two together.

I don't have that book. Is he really talking about the A-12 or does he mean the YF-12A?

I don't have that book. Is he really talking about the A-12 or does he mean the YF-12A?

it's design was such that there was NO payload space except for the camera

Prior to the SR-71's development, a variation of the A-12 called the YF-12 was developed that actually had a payload of bombs and/or AA missiles.

Ian

Amen.

From what I recall, the SR71 offered a task that no satellite or U2 could perform - high-speed, on-demand surveillance overflights of not-yet-completely-controlled airspace. Sending a U2 into enemy territory without adequate SAM surpression is a very bad idea (ask Gary Powers, who probably still has burn scars on his ass... unless he's dead by now). The raw speed of the SR71 means that a) it can get there faster, so that action, before the party's over, and b) it is harder (altho not impossible) to shoot down. Wasn't there something about the US finding Bin Laden during the first few days of the campaign but not getting proper surveillance data soon enough?

I'm reminded of a scene in a Tom Clancy film (Clear and Present Danger?) where terrorists at a desert training camp hide all of their equipment during satellite overflight times, much like the white folk stopped their partying when the black man got on the bus in that oft-referenced SNL skit. Also, while one can argue that satellite imaging resolution is much more advanced than it was when the SR71 was conceived, and that such might reduce the utility of the SR71, would not the equipping of an SR71 with the same upgraded optics allow even *greater* imaging capabilities? I think to those satellite images shown during the press briefings during the early part of the Afghanistan campaign... "and this slide shows a runway... err, no wait, I think it's a... oh sorry folks, this is my son's biology experiment, let me just change that" - surely greater detail would help? (I'm sure the US military has better slides than it shows up, but the same "get the camera closer" logic applies in either case.

Anyone that is remotely interested in the SR71 or the U2 or surveillance / stealth planes in general owes it to themselves to read Skunk Works. There is also a decent SR-71 site that even has the flight manual (recently declassified) online! In case you ever find one left running unattended at the local 7-11, natch.

Amen.

From what I recall, the SR71 offered a task that no satellite or U2 could perform - high-speed, on-demand surveillance overflights of not-yet-completely-controlled airspace. Sending a U2 into enemy territory without adequate SAM surpression is a very bad idea (ask Gary Powers, who probably still has burn scars on his ass... unless he's dead by now). The raw speed of the SR71 means that a) it can get there faster, so that action, before the party's over, and b) it is harder (altho not impossible) to shoot down. Wasn't there something about the US finding Bin Laden during the first few days of the campaign but not getting proper surveillance data soon enough?

I'm reminded of a scene in a Tom Clancy film (Clear and Present Danger?) where terrorists at a desert training camp hide all of their equipment during satellite overflight times, much like the white folk stopped their partying when the black man got on the bus in that oft-referenced SNL skit. Also, while one can argue that satellite imaging resolution is much more advanced than it was when the SR71 was conceived, and that such might reduce the utility of the SR71, would not the equipping of an SR71 with the same upgraded optics allow even *greater* imaging capabilities? I think to those satellite images shown during the press briefings during the early part of the Afghanistan campaign... "and this slide shows a runway... err, no wait, I think it's a... oh sorry folks, this is my son's biology experiment, let me just change that" - surely greater detail would help? (I'm sure the US military has better slides than it shows up, but the same "get the camera closer" logic applies in either case.

Anyone that is remotely interested in the SR71 or the U2 or surveillance / stealth planes in general owes it to themselves to read Skunk Works. There is also a decent SR-71 site that even has the flight manual (recently declassified) online! In case you ever find one left running unattended at the local 7-11, natch.