Lockheed SR-71 / YF-12 Blackbird

Orionblamblam said:
taildragger said:
The photo below was taken about 5 years after the start of the Blackbird's test program and I'm unaware of any revolutionary advances in tracking or photography that occurred in the interim. The subject vehicle is somewhat larger but is moving faster (6,164 mph) and at higher altitude (220,000 ft.) than the Blackbird family is generally believed capable of.
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1) It's not just somewhat larger, it's a *lot* larger.
2) The vehicle isn't approaching from the dim vague distance, but was clearly observed from the beginning, RIGHT OVER THERE, with massive camera tracking rigs built for the purpose.
3) Launch vehicles go up and over, not more or less purely horizontal. That Saturn V isn't visible low in the sky, but *high* in the sky. Far less air to look through than something lower-yet-closer but closer tot he horizon.
4) Launch vehicle trajectories are pre-programmed; but whenever there's a divergence the manual trackers tended to lose them almost instantly.
5) Launch vehicles were painted *white* in large part so that they could be clearly seen. Look at the bottom of the Saturn V S-IC stage in your photo: it's dark... and essentially the same color as the background. All that you can see of the Saturn V is what's painted white; the black bits are truly invisible.

In order to be seen for a 1965 speed record run, a YF-12A was painted with a white cross. Without it, it would have been damned difficult to see at altitude.

Lockheed-YF-12A-60-6936-with-white-cross-on-belly-2.jpg


Before assuming some whackaloon conspiracy about the SR-71 family using "plasma stealth" or some such rubbish as an excuse for why it hasn't been photographed... find some photos of the U-2/TR-1 at altitude. Roughly the same color as the SR-17, roughly the same size (TR-1 span 103 feet, SR-71 length 107 feet), but flies a little lower (70K vs 85K) and a *lot* slower. Should be vastly easier to spot and photograph. Go ahead, look 'em up. Should be oodles of them.
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So your contention is that:
1. It was possible (in 1965) to track a Blackbird at speed and altitude when the aircraft was marked with a large white cross
2. This was done to support a speed record run
3. It's ridiculous to suppose that the same measures would be used to photographically document the airplane in its intended operational speed and altitude during it's test flight program. After spending billions of dollar and pushing many technologies into unprecedented territory. Because spyplanes fly low on the horizon and you couldn't pre-program a test flight to pass over a camera on schedule.
4. Suggestions that the USG might wish to restrict photos of a CIA-sponsored spyplane performing at a speed and altitude unreachable by any other aircraft, because they might reveal something of the technology employed are "whackadoodle".
Sorry, I lost your line of reasoning there somewhere.

BTW, you introduced "plasma-sheath" into the conversation.
I freely admit that I'm speculating but am touched by your certitude that 50+ years ago, when testing arguably the world's most advanced aircraft, no-one would think it worthwhile to document photographically it demonstrating unprecedented capabilities in conditions no aircraft had ever experienced before.
 
taildragger said:
So your contention is that:
1. It was possible (in 1965) to track a Blackbird at speed and altitude when the aircraft was marked with a large white cross
2. This was done to support a speed record run
3. It's ridiculous to suppose that the same measures would be used to photographically document the airplane in its intended operational speed and altitude during it's test flight program. After spending billions of dollar and pushing many technologies into unprecedented territory. Because spyplanes fly low on the horizon and you couldn't pre-program a test flight to pass over a camera on schedule.
4. Suggestions that the USG might wish to restrict photos of a CIA-sponsored spyplane performing at a speed and altitude unreachable by any other aircraft, because they might reveal something of the technology employed are "whackadoodle".
Sorry, I lost your line of reasoning there somewhere.
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1: Correct.
2: Duh.
3: Incorrect.
4: Incorrect.

See what happens when you dream up strawmen and say "so your contention is..." rather than asking for clarification on points you clearly don't understand?


taildragger said:
BTW, you introduced "plasma-sheath" into the conversation.
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No, I didn't. Do a ctrl-F search for "plasma" and see where it pops up first.

Looking forward to your photos of the U-2 at altitude.
 
[B]TomcatViP[/B] said:
We have famous pictures like the one shot from one SR-71 while crossing the path of another above the Pacific at Mach 3.

We also have the M-21 camera shot.

We also have the ejection sequence filmed from the ground.

However, the A-12 high speed early flights should be interesting to see (plasma stealth?).
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Thank you @quellish for the links. Allways usefull to look back into all that. Your links were high precision.

Although I did not bought the ARC book, here is an extract that make it inevitable:

Screenshot_20200708_141748.jpg

So indeed I was the one introducing Plasma stealth into the discussion. The lack of photographic evidence is noteworthy and I still believe that there is a part of the story that remain uncovered.
 
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TomcatViP said:
The lack of photographic evidence is noteworthy...
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The lack of photos of an aircraft that would be basically invisible at altitude is noteworthy? KEMPSTER would have hardly made a difference here; it's probable that, apart from minor configuration differences such as the Bunce Bump, there would be no visible evidence of the system even if you were standing next to it getting a face full of X-rays.
 
Orionblamblam said:
taildragger said:
So your contention is that:
1. It was possible (in 1965) to track a Blackbird at speed and altitude when the aircraft was marked with a large white cross
2. This was done to support a speed record run
3. It's ridiculous to suppose that the same measures would be used to photographically document the airplane in its intended operational speed and altitude during it's test flight program. After spending billions of dollar and pushing many technologies into unprecedented territory. Because spyplanes fly low on the horizon and you couldn't pre-program a test flight to pass over a camera on schedule.
4. Suggestions that the USG might wish to restrict photos of a CIA-sponsored spyplane performing at a speed and altitude unreachable by any other aircraft, because they might reveal something of the technology employed are "whackadoodle".
Sorry, I lost your line of reasoning there somewhere.
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1: Correct.
2: Duh.
3: Incorrect.
4: Incorrect.

See what happens when you dream up strawmen and say "so your contention is..." rather than asking for clarification on points you clearly don't understand?


taildragger said:
BTW, you introduced "plasma-sheath" into the conversation.
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No, I didn't. Do a ctrl-F search for "plasma" and see where it pops up first.

Looking forward to your photos of the U-2 at altitude.
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Thanks for your insights and for the fruits of your towering intellect.
 
taildragger said:
Thanks for your insights and for the fruits of your towering intellect.
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Anytime. That's why I'm here.

And again, looking forward to your postings of photos of the U-2 (or, heck, any black-painted aircraft) at extreme altitude to show just how easy they are to photograph with crystal clarity. Heck, when I go looking for that sort of picture, I come across stuff like this:

E6B.png


That's a light-colored/bare-metal jetliner substantially bigger than the U-2/SR-71 flying at half to a third the altitude, and already it is beginning to fade into the background. Without the contrails you'd barely be able to see the thing. But *surely* a smaller aircraft, much further away, painted specifically to blend into the background... why, that's stick out like a MAGA hat at a Bernie rally!
 
Apart from reminding us to that great aircraft, mentioning the problems with photographing aircraft (or better, any
flying objects) at height are interesting food for thought indeed.
But perhaps this discussion could be run with less sarcasm and malice ... from all sides ?
 
Ionisation do alter photon travel thanks to absorbtion. So a color picture of such plane zipping through the atmosphere with localized formed plasma would be identifiable. Any observatory telescope could be tasked to do that. With so many territory overflown during A-12 missions, we might one day have a chance to see one such picture emerge...
 
Archibald said:
Seems they flew three U-2 missions from Charbatia to Lop Nor and back, circa 1964. From memory, with ROCAF pilots.
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The ROCAF's Squadron 35 (The Black Cat Squadron) used U-2s for mainland China overflights from January 1962 to March 1968 (after that only missions outside the borders of PRC were allowed).
The first idea for a flight to Lop Nor came in middle 1964, using a taiwanese U-2 but with an american pilot (the flights from Taiwan were strictly controlled by USA, and only authorized and flown by ROCAF), but at the end the mission was never made.
Only on 7 May 1967 the first mission (code C167C, the 93th overflight of PRC) to Lop Nor was made from Takhli (Tahiland), using a taiwanese U-2 on a very special mission: dropping two sensors to record the seismic activity of the nuclear explosions (Project Tabasco). The sensors would extend an antenna to send signal to a USA SIGINT station at Taiwan, but the data were never received. The analysts presumed the signals were not to strong enough to be received so far, so they decided to make another mission to Lop Nor using an U-2 with data receiver onboard, developed in short time and using an long wire as an antenna, spun from the Q-bay. The antenna would be recovered onboard, but in case of a malfunction of the reel a cutting device would cut the wire.
The mission (code C287C) was flown on the night 30-31 August (btw, it was the 100th overflight of mainland China performed by the 35th Squadron); it was a frightening mission, with a couple of SA-2 exploding near the U-2, but the pilot continued the flight, though the receiver did not record anything. During that period the first Chinese thermonuclear bomb was tested at Lop Nor (June 17), so a lot of interesting data would be recorded...

More details on Chris Pocock "50 years of the U-2", Schiffer, 2005 (and on an article written by myself in 2017 about the Taiwanese U-2s for an Italian magazine :cool:).
You can find below the redacted mission resume of the second flight, taken from the CIA library.
 

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  • 1967-08-31 Mission C287C CIA-RDP68B00724R000200090023-6.pdf
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Whisperstream said:
>snip lots of good stuff<

The Blackbirds ultimately earned their nickname because they were coated with a high-emissivity black paint for improved heat radiation, thus reducing thermal stresses on the airframe. Although the first A-12 flew unpainted, engineers soon realized it would be advantageous to exploit Kirchoff’s law of Radiation that describes how a good heat absorber, such as any extremely dark object, is also an efficient heat emitter. Although convective heating decreases with increasing altitude, heat radiation occurs independently of altitude. Initial efforts involved application of black paint only to the airplane’s edges and cockpit area. The earliest paint scheme used on the A-12, AF-12 (YF-12A), and M-21, and intended for use on the R-12 (SR-71), involved painting the periphery black and leaving the rest of the airframe natural metal. Beginning in late 1963, however, Skunk Works engineers began painting the A-12 fleet and subsequent variants entirely black. This improved heat emission and made the airplanes less visible from the ground since they no longer strongly reflected the sun during high-altitude flight.
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Yes... and the paint did NOT react well too standard aircraft washing soap. In fact a good number of people at Eglin AFB around 1980/81 found out the hard way that the several hours used to "mark" a visiting Blackbird with 'standard' AFB markings (for Eglin) on the tails with said aircraft soap (to take pictures of the aircraft for the base paper) were rather near-career-ending for many of them, including several people I knew.

A very stressful week and a half was had instead of the planned 48 hour 'visit' and that included two trips through the McKinley Climatic hanger (https://en.wikipedia.org/wiki/McKinley_Climatic_Laboratory) to try and scrape the frozen soap off without damaging the paint.

Randy
 
TomcatViP said:
Nice one. Also 120 mile front aspect detection range for an SR-71 from an YF-12.
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The F-12B is one of those great, "might have beens". (Not sure how practical it would have been to use them to escort Bears though.)
 
You've have to appreciate the modesty of such heroes (super?!) when they have to awnser where above the one digit mission they flew in a 6/7 years training were: "huh... Korea... Vietnam" . Why not Paris and The Chicago century fair!

I did watch this interview dozen of time and still feel breathless like each one of those
 
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Cost per flight hours (1997): 37000$ (~8% of a Space Shuttle launch).
 
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The above relates only to the SR-71...
@admin : Wasn't there any more suited place to past that post other than in the vast empty Secretverse?
 
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‘Noteworthy, JP7 production caused a nationwide shortage of bug spray,’ says our friend Linda Sheffield Miller (Col Richard (Butch) Sheffield’s daughter, Col. Sheffield was an SR-71 Reconnaissance Systems Officer) on her Facebook Page Habubrats.
[...]
Sheffield Miller explains;

‘Shell Oil developed JP-7 in 1955. Company vice president Jimmy Doolittle arranged for Shell to develop the fuel for the Central Intelligence Agency (CIA) and United States Air Force’s (USAF) secret Lockheed U-2 spy plane, which needed a low-volatility fuel that would not evaporate at high altitude. Manufacturing several hundred thousand gallons of the new fuel required the petroleum byproducts Shell normally used to make its Flit insecticide, causing a nationwide shortage of that product!

‘One of the ingredients in JP7 just so happened to be a crucial part of Flit mosquito repellant. Bearing in mind the huge amount of fuel we’re talking about here, Shell didn’t exactly have enough supply to meet the newly increased demand, so mosquitos everywhere caught a lucky break!’
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theaviationgeekclub.com

JP-7, the fuel that powered the SR-71 Blackbird caused a nationwide shortage of bug spray. Here’s why. - The Aviation Geek Club

JP-7, the fuel that powered the SR-71 Blackbird caused a nationwide shortage of bug spray. Here’s why.
theaviationgeekclub.com theaviationgeekclub.com
 
tacairnet.com

Blackbird’s Revenge

A while back, I came across a fantastic recollection from a former SR-71 pilot of the United States Air Force about his experience at an airshow in England in the 1980s. It’s just too good no…
tacairnet.com tacairnet.com

Blackbird washes protesters with afterburner pull up blast.
 
KwaZulu said:
tacairnet.com

Blackbird’s Revenge

A while back, I came across a fantastic recollection from a former SR-71 pilot of the United States Air Force about his experience at an airshow in England in the 1980s. It’s just too good no…
tacairnet.com tacairnet.com

Blackbird washes protesters with afterburner pull up blast.
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Interesting story, but hard to verify if true. I lived near Greenham Common at the time the SR71 visited for the International Air Tattoo (it was 1983, not 1985 as suggested in the link above, the IAT moved to Fairford from 1985). I was 14 in 1983, so at school at the time and remember the Blackbird's approach being visible from the classroom I was in on the day it arrived - it came around before landing so we saw the approach with gear down twice - it was not a productive lesson for the teacher!

The location of the peace camp was to the south of the base, at the main entrance, by a busy road and parallel to the main runway. In order to overfly the camp the SR71 would have had to take off, go around and fly low over the main road as well as the main entrance, meaning it likely that this spectacular departure would have had many witnesses and been reported in the local media. The hardened cruise missile shelters were also to the south edge of Greenham comon, to the east of the main entrance. This would have also meant getting permission to overfly close to the shelters. Like I said, not saying it didn't happen, but seems more likely to be a great story than reality. In the UK at this time the peace campaigners were major news, and run-ins between them and base securty/local police were regularly reported, so seems a long shot this wouldn't have been picked up in the media.
 
Alex from Sandboxx has just uploaded this interesting video:


There's a book on the SR-71 that I bought back in the 1990s where I distinctly recall reading that the uppermost possible speed for the Blackbird was Mach 3.7 due to its' air intake geometry.
 
NMaude said:
There's a book on the SR-71 that I bought back in the 1990s where I distinctly recall reading that the uppermost possible speed for the Blackbird was Mach 3.7 due to its' air intake geometry.
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Somewhere in the range 3.5 to 3.7 is also where the Mach shockwave would start impinging on the wingtips and nacelles. That would be a Bad Thing as it would cause localised shockwaves, unmanaged stresses and additional heating, plus it would flame out the engines if it hit the cones.

Edit: From a NASA Dryden 3-view of the 71B, guesstimating that things start to get aerodynamically nasty around Mach 3.56 ( cone angle 16.43 deg ). Interestingly both the chine and the wingtip start impinging the shockwave above that, so it will be interesting to look at the YF-12 and its cut-back chines.

Edit 2: Dryden diagram of YF-12 suggests cone limit of pretty much the same, Mach 3.55, though there's much more clearance around the chine. That does suggest that the SR's chine was expanded to make most use of the planform-dictated cone limit which in turn gives evidence to this being the true limit of the SR's design speed.
 
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Per a couple of SR71 pilots, the Blackbirds are all temperature limited, and the pilots usually flew by temperature, not Mach number.

427degC Compressor Inlet Temp usually corresponds to about Mach 3.2, but when you're up over the Arctic Circle in wintertime it's faster than that. Slower than that if you're down over the tropics in summertime.

The other two catches are
1) that the inlet spikes run out of travel at Mach 3.55 and unstart the inlets if you try to go faster; and
2) that the nose shock will contact the ailerons at the wingtips at M3.55 and start breaking things.

So if you know your mach cone angles, you can lay out a protractor over a top-down picture of any jet and get a good guess as to the maximum possible speeds: Where the Nose shock cone just touches the wingtips, then round down a little.
 
Great points by Scott Kenny, above. It's hard to believe this is still a subject of debate after so much technical data regarding the Blackbirds has been declassified.

Mach 3.32 was the design cruise speed, but maximum allowable Mach number was dependent on outside air temperature and its effect on compressor inlet temperature (CIT). The pilot was authorized to accelerate to Mach 3.3 as long as CIT remained at or below 427 degrees Centigrade. Speeds exceeding Mach 3.3 were occasionally recorded, but generally the pilot tried to avoid this area of the performance envelope because it placed excessive thermal stress on the airframe.

Some maximum speed milestones achieved by various members of the Blackbird family:
YF-12A, 1 May 1965, Mach 3.14 (2,070 mph)
A-12, 8 May 1965, Mach 3.29 (2,171 mph)
SR-71A, 28 July 1976, Mach 3.32 (2,193 mph)

In 1975, Lockheed studied the possibility of expanding the flight envelope of the SR-71 with some modifications. The results of several studies concluded the maximum speed limit could be extended to Mach 3.5 for short periods of time. The only structural limit to speeds above Mach 3.5 was a KEAS (knots equivalent airspeed) limit of 420, set by inlet duct pressures and temperatures that exceeded acceptable values at that point. Limited inlet capture-area and excessive engine CIT also limited operation at higher Mach numbers, even with proposed modifications.
 
This just popped up today on YouTube from Sandboxx concerning the YF-12 and its speed (It was faster than the SR-71):


Lockheed's legendary SR-71 may hold the record for being the fastest production jet in history, but more than a year before the first Blackbird took flight, President Lyndon Johnson was already revealing the YF-12 to the world... An aircraft that promised to be the fastest intercept fighter the world has ever seen.
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Let's talk about what the F-12 could have been, and why revealing it was actually part of a broader ploy to keep the A-12 and SR-71 under wraps.
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It made sense for the high-speed interceptor to be revealed first to provide cover for the A-12 and SR-71, IIRC the F-12 had a top speed of M3.5.
 
If you take a look at the cockpit mach indicator for the A-12, YF-12 and SR-71, you will see dashes from m3.5 to m4.0, interesting, just an observation.
 

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