Lockheed SR-71 / YF-12 Blackbird

Halcyon66 said:
Seems illogical to get a 59-yr old extreme high-performance airframe back in the air?
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Seems logical to me. Barring the cost/effort of recommissioning its the obvious solution for a Mach 3+ chase plane for some higher speed research project, or alternative propulsion testing (aerospike anyone?). Remember, there is still nothing in day-to-day service that is faster. The SR-71 is still the only operational jet that could cruise at that speed. And remained in service doing so for ~30 years. There is nothing else in the USA's portfolio (that we know of) which has this sort of pace, range, and robustness. The pilots and RSOs when discussing the various records they set all confirm that no special measures were taken regarding aircraft prep, they were just another typical mission.
NMaude said:
Once they were retired by the USAF it's a pity NASA didn't get some of the A-12 Oxcarts for high-speed research.
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NASA were busy playing with the X-15s during the 1960's, what would they need something slower for?
 
NMaude said:
Once they were retired by the USAF it's a pity NASA didn't get some of the A-12 Oxcarts for high-speed research.
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In 1968 ? NASA got the YF-12s plus a handful of SR-71s later. They didn't needed A-12s.
NASA were busy playing with the X-15s during the 1960's, what would they need something slower for?
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Not comparable. Brief rocket flights versus long Mach 3 cruises.
 
yeetmahboi said:
Only that we don't know of. The SR-71 was classified back then, there could be one flying right now...
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Which I acknowledged further on in my post. And technically, wasn't the A-12 classified, with the SR-71 public knowledge but the operations of which were classified?
 
yeetmahboi said:
Only that we don't know of. The SR-71 was classified back then, there could be one flying right now...
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All the surviving A-12, YF-12A, and SR-71 airframes are in museums. Most had their wing spars cut before being transported to their final destinations, rendering them unflyable. There are none flying now.
 
Halcyon66 said:
I am pretty sure the amount of $$ that this will end up costing they could have just built a few of the SR-72.

Seems illogical to get a 59-yr old extreme high-performance airframe back in the air?

Lockheed SR-71A tail number 844 (USAF serial number 61-7980) first flew on September 25, 1967.
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I've read that every flight and heat soak re-heat treated the entire airframe. So the actual wear on the airframe is minimal.



Whisperstream said:
All the surviving A-12, YF-12A, and SR-71 airframes are in museums. Most had their wing spars cut before being transported to their final destinations, rendering them unflyable. There are none flying now.
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There's a deliberate break in the spars just inboard of the engines, where they could unbolt the engine nacelles to ship them to Groom Lake.
 
Whisperstream said:
All the surviving A-12, YF-12A, and SR-71 airframes are in museums. Most had their wing spars cut before being transported to their final destinations, rendering them unflyable. There are none flying now.
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I believe they meant another classified aircraft flying, not an SR-71
 
@Whisperstream you seems to know a lot about SR-71 post 1998 retirement fates.
Looks similar to F-14s fates past 2006.
Unfortunately...
 
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Whisperstream said:
All the surviving A-12, YF-12A, and SR-71 airframes are in museums. Most had their wing spars cut before being transported to their final destinations, rendering them unflyable. There are none flying now.
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I mean that there is another classified airplane doing its work today.
 
I can't find the posts here (my search-fu is weak), but someone was posting all about the origins of the stealth recon drone associated with the ATB/B2. Can anyone help a brother out?
 
I tell you why they are doing this, at least in part, Isaacman probably fancies flying it.

Also chase plane for something even faster than it?

At another AirVenture panel, Isaacman was asked which aircraft he would like to fly but had never flown. His immediate answer was the SR-71 Blackbird. This led the moderator to ask whether he had the authority to bring one back, with Isaacman replying: “That’s classified.”

Obviously, none of those comments constitutes confirmation that NASA is restoring the SR-71 to fly again. However, they provide an intriguing backdrop to what is otherwise an unexplained move.
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https://theaviationist.com/2026/09/28/is-nasa-sr-71-blackbird-returning-to-flight/
 
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I’m guessing the funding for this isn’t actually coming from NASA but elsewhere?
 
NMaude said:
And those spars can be fixed.
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There's a bolted joint just inboard of the engine nacelles. Which does leave the blackbird a very oversized load on a trailer, but it's not a terminal problem.

Edit: Not a "this airframe can no longer fly" problem. The Blackbirds were all initially driven with the nacelles dismounted, inside the goofiest looking trailer you've ever seen, from Palmdale to Groom Lake, and then had their nacelles bolted onto the wing stubs at Groom Lake. Later on, once the shape was no longer classified they were flown, but at the very least the A-12s were all driven to Area 51.
 
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Flyaway said:
I wonder if this could end up as a test bed for Hermeus. Apparently they recently got the okay to license build F100 cores for their engine. If anybody wanted to suggest an engine to fit into the J58 hole, that would be it. Are they even funding this?

https://hermeus.com/propulsion#chimera-II
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The J58 was approximately a 300 pounds per second engine at sea level static. F100-229 is 250 pps, F110-129 is 270 pps with -132 at 275 pps. The intake has to be sized for the airflow at supersonic speeds. How the turbofans will flow compared to the bleed bypass J58 at the high Mach inlet temperatures is TBD.

The A-12/SR-71 had both forward bypass (vented overboard) and aft bypass (vented around the engine thru the exhaust nozzle) channels that could be adjusted to match the engine plus bypass flow to the inlet flow requirements to avoid unstart. The F-22 has overboard bypass louvers to match the inlets to the F119 flow characteristics at various supersonic flow conditions. Will be interesting to see what NASA and Hermeus are up to.
 
NMaude said:
Is the 300lb/s the maximum intake airflow at the compressor face?
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No, once the airframe starts moving you get ram effect packing more lbs of air in there.

I know there is a conversion somewhere between inlet pressure and lbs of air, but I don't have a good number for the ram air pressures.



J58 is also a couple inches larger in diameter than the F100, so installing a bigger fan would be an option.
 
Here's a new video concerning NASA pulling its' SR-71 from its' museum display and lack of explanation as to why it was removed:


Today we discuss the SR-71 Blackbird that vanished from NASA Armstrong. Tail 844, the last Blackbird ever built and the last to fly, is gone from its display and NASA will not say where.
​


Aviation Week defense editor Steve Trimble broke the story using satellite imagery showing the aircraft missing since at least 17 May 2026. Joseph Trevithick at The War Zone followed up, and NASA's response was that it has no additional information to share, while noting it continues to explore opportunities to build on that legacy.

The timing is what has everyone talking. NASA Administrator Jared Isaacman recently teased a new X-plane using a silhouette that looks a great deal like a Blackbird, and said the agency intends to fly higher, farther, and faster than it has in decades. Asked at AirVenture Oshkosh in July whether he would bring the SR-71 back, his answer was "that's classified."

Aviation Week has since reported that NASA reached out to former employees about returning to an SR-71 effort. One former Air Force and NASA test pilot, now in his late seventies, turned it down. His words: "I just don't think you can get there from here."

Tail 844 flew its last mission on 9 October 1999, reaching 80,100 feet and Mach 3.21 with NASA pilots Rogers Smith and Robert Meyer. It has sat in flyable storage at Armstrong since March 2002.

Getting it airborne again means JP-7, a fuel with a flash point high enough that the airframe used it as a heat sink. It means triethylborane shots to light the J58s, sixteen per reservoir. It means the tanker problem: 56 KC-135s were converted to KC-135Q between 1966 and 1968 with separated tanks purely to carry JP-7 for the Blackbird.

This is not the first attempt. Congress allocated $100 million in 1994 to return three SR-71s to Air Force service. The aircraft were grounded in 1996, funding came back the same year, and a line item veto killed it in 1997. The Air Force program formally ended on 30 June 1999 at Det 2, Edwards. After 9/11 the Pentagon asked what a restart would take and was told 60 to 90 days and roughly $45 million.​

0:00 The Mysterious Disappearance of the Blackbird
1:31 The Best Candidate for a Return to Flight
2:35 Recruiting Veterans for a New Mission
4:04 The Complex Science of Specialized Fuel
7:13 A History of Political and Technical Hurdles
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NMaude said:
Is the 300lb/s the maximum intake airflow at the compressor face?
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yes, with a zero restriction test cell bellmouth and sea level standard day conditions (14.7psi, 59F).

Actual airflow installed varies throughout the flight envelope. Increase in altitude lowers ambient pressure and airflow, increasing speed ram recovery increases inlet pressure and airflow. Increasing Mach number increases inlet temperature, which lowers corrected rotor speed and airflow once the engine RPM reaches its physical (and governed) limit.

Matching the engine flow characteristics with the inlet geometry is a challenge, especially with the Blackbird mixed compression inlet. Maintaining the internal shock positions is critical to preventing inlet unstart.
 
Halcyon66 said:
Former SR-71 Engineer Talks NASA’s Blackbird Revival Program

https://www.twz.com/air/former-sr-71-engineer-talks-nasas-blackbird-revival-program

Regards,
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Late last month, we wrote about how satellite imagery taken over Armstrong showed that Tail 844 had been missing since at least May. The revelation was first made by Steve Trimble, Aviation Week‘s defense editor and friend of TWZ.
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I'm pretty sure @Whisperstream beat Trimble to it:
https://www.secretprojects.co.uk/threads/mysterious-x-plane-from-nasa.52331/post-944751

And I am pretty sure that post is un-attributed source of the "Missing Blackbird" stories that have resulted.

Disappointing that Trimble didn't attribute his source.
 
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While we don't know what NASA is doing with 844 I hope (Even though it take some time and a LOT of money) to see the Blackbird flying again, it's such a magnificent, beautiful and very elegant flying-machine.
 

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