Aurora/SR-72/SR-91 ?

What I do know is that Aerojet Rocketdyne just within the last few years has been able to build a much more successful combine cycle engine  that didn’t melt away after running for a few minutes. The recent advances in 3d metal printing technology has helped them build in much better cooling fluids channels thru the combustion chamber.  If there still moving forward 🤷🏻‍♂️

NASA funded the engine side of that project in…2014-2015(?)…well…back then I believe they gave Lock-Mart some $ & Rocketdyne some $ to continue development of the combined cycle system…and I think Rocket developed a demonstrator via another DARPA program…or actually flew it in another project…which I’m thinking people are still associating with the SR72 program…? 

Some folks have even reached as far as to say the c-c engines will be in the F47; but, who knows…that doesn’t make sense…all the while…the 47 does have some design elements from the bird that Maverick flew in the recent movie 🤣

The F47 engine either from Pratt &Whitney or General Electric turbofan but 6th generation tech. My feeling is that they are going to push forward with the SR72 mainly for 2 reasons both drone and hypersonic are the future,  put them together well that become pretty potent threat. Just my opinion. 

There is an ongoing AFRL (Air Force Research Lab) project called Mayhem. It has a lot of similarities in this project that mirrors what the SR72 would be used for, well trying to accomplish. The SR72 would be used by the Air Force so maybe it’s the same project but just different sides of it.  Rocketdyne is owned by Lockheed. 

Everyone knows the SR-71 Blackbird. Far fewer people know that before the Air Force ever flew it, the CIA was secretly operating an even faster version of the same design, and would deny its existence for the next 30 years.

That aircraft was the Lockheed A-12, code named Oxcart. It was the Blackbird's predecessor, designed by the same legendary team at Lockheed's Skunk Works under Clarence "Kelly" Johnson, and it flew first. Where the SR-71 was a two seat aircraft built for and flown by the US Air Force, the A-12 was a single seat machine built in secret for the Central Intelligence Agency.

A SECRET FROM THE START

The A-12 was created to solve one Cold War problem: how to fly over hostile territory, photograph it, and get out before anyone could react, all without sparking a war. It first flew in 1962 and was declared operational in 1965. The program was classified so deeply that for decades the government would not admit the aircraft existed. It was only acknowledged publicly in the 1990s, long after it had stopped flying.

FASTER THAN THE PLANE IT INSPIRED

Here is the part that surprises even aviation fans. The famous SR-71 is usually called the fastest of its kind, but the CIA's A-12 was actually a touch faster and flew higher. Being smaller and lighter than the Air Force version, it reached sustained speeds around Mach 3.29 at altitudes near 90,000 feet. The Blackbird everyone remembers was the more capable all rounder, carrying a wider array of sensors, but the CIA's plane was the quicker of the two.

FLYING THE REAL MISSIONS

The A-12 did not just sit on a runway. A small fleet flew real reconnaissance missions over Southeast Asia during the Vietnam War, and the type's final operational flight was over North Korea in 1968, after the seizure of the American ship USS Pueblo.

HANDING OFF THE LEGEND

By 1968, the A-12's days were numbered. Reconnaissance satellites were improving fast, running both a secret CIA fleet and the Air Force's new SR-71 was expensive, and the decision was made to keep just one. The A-12 was retired, the SR-71 took over, and it was the Air Force's Blackbird that went on to become a household name. But the plane that started it all, and flew faster than the legend, belonged to the CIA.

It's crazy to think more than 60 years ago the technology that went into this aircraft was just freaking amazing! 😲

This is how they knew that they could fly around the world and how much it would cost when they were thinking about a bicentennial around the world flight. They decided on a speed record instead. But the records that were set were not the true absolute limits of the SR 71 blackbird

On Apr. 26, 1971, pilot Lt. Col. Thomas Estes and RSO Lt. Col. Dewain Vick (he and his family were one of my neighbors at Beale AF flew SR-71 #968 15,000 miles in 10 hours 30 minutes non-stop on a grueling marathon mission to test the endurance of the J58 engines and the Blackbird airframe, but mostly to see how many times they could refuel before the liquid nitrogen gave out. At Blackbird speeds and temperatures, oxygen becomes explosive and can spontaneously ignite in the tanks and fuel lines. In order to prevent this, all 6 fuel tanks are purged with pure nitrogen after being filled.

The Blackbird also carries 260 liters of liquid nitrogen in 3 dewars [for this flight the SR-71 only had 2 – 106 liter liquid nitrogen dewars. The 3rd 50 liter dewar was added in the mid 1980’s]. This nitrogen expands into its gaseous form as it is pumped into the fuel tanks to top them off as fuel is consumed. Without the nitrogen, the empty fuel tanks would cavitate from the increased pressure when returning to lower altitudes to refuel. This process involves pumping nitrogen into the tanks while allowing air to vent out, which removes oxygen from the fuel and makes it chemically inactive. This greatly reduces the risk of explosion in extreme heat and pressure conditions.
Linda Sheffield

Pretty cool video reel on how the SR-71 changed from a Turbojet to a RAMjet once it got to 30,000ft and Mach 3. 

Just once again proving how Kelly Johnson and his Engineering team were so far ahead of their time and others.

https://www.facebook.com/share/r/194h93oPXn/

Highly recommend the book Area 51 by Annie Jacobsen. A lot of interesting background on the A-12.

So the Lockheed competition was the Convair KINGFISH. Look that up it’s was pretty cool also.

The Pratt-Whitney J58 guys in Palm Beach had a lot to do with that,  my Dad was a test engineer there and spent about 6 months at Area 51 in the mid 60s

Wow, that is awesome! Is he still alive? Was he able to ever tell you any stories, or did he have to keep his lips sealed?

Don't worry, this will just be between you and me.😜

Sadly he passed in 2010, we really never got to hear any fascinating stories, he made it sound like just work, I do have his slide rule and some SR71 documentation but there is/was a group called the Roadrunners that would have gatherings and lots of stuff was declassified and available 

Skunk Works founder Kelly Johnson gave this particular SR-71, tail number 960, a harsh verdict after its first near-disaster: "the only Blackbird that ever flew that was structurally unsound," the result of a 1968 engine fire at Mach 2.88 that left the wing structure heat-warped. Sixteen years later, in May 1984, the same jet caught fire again, this time during a public air show at Andrews Air Force Base, the right engine's nacelle blowing apart on takeoff and tearing into the wing's leading edge in front of a crowd. The pilot shut down the burning engine and brought both crew safely back to the runway, and by the time it was over, this was the third time #960 had come close to being lost for good, according to the daughter of one of its RSOs. Today the jet everyone nicknamed "the cat with nine lives" sits on permanent outdoor display at Castle Air Force Base, California