SR71

The first aircraft to use its own fuel for hydraulic fluid was the SR-71 Blackbird and it was called the fuel hydraulic system

The legendary SR-71 Blackbird Mach 3+ spy plane was powered by two 34,000 lbf (151,240 N) thrust-class J58 afterburning turbojet engines. Each engine contained a nine-stage compressor driven by a two-stage turbine. The main burner used an eight-can combustor and the afterburner is fully modulating. The primary nozzle area was variable. Above Mach 2.2, some of the airflow was bled from the fourth stage of the compressor and dumped into the augmentor inlet through six bleed-bypass tubes, circumventing the core of the engine and transitioning the propulsive cycle from a pure turbojet to a turbo-ramjet.

The SR-71 was the first aircraft to use its own fuel for hydraulic fluid, called the fuel hydraulic system.

An engine-driven pump provided 1800 psi of recirculating fuel to accurate various engine components and then returned it back to the aircraft fuel system to be burned. Fuel was used in the actuators to control the afterburner nozzles, maintain the proper exhaust gas temperature, and control the thrust output. The fuel was also used in the engine actuators to shift the two-position inlet guide veins from their axial position to the cambered position and back again. This was just another of the many first-ever inventions of the SR-71.

The J58 engine was hydromechanically controlled and burned a special low-volatility jet fuel mixture known as JP-7.

Emergency fuels could be used in the SR-71 if the crew was low on fuel and had to use ANY tanker (as already explained, the Blackbird relied on KC-135Q tankers [that could simultaneously carry a maximum of 74,490lb of JP-7 and 110,000lb of JP-4 for their own engines], but the SR-71 could also be refueled by standard Stratotankers in the event KC-135Qs were not available or if the Blackbird crew had to deal with an emergency situation) they could find to avoid the loss of the aircraft. The emergency fuels were JP-4 or JP-5, but they limited the Blackbird’s top speed to Mach 1.5. There were six main fuselage tanks. All 80,285 pounds of JP-7 fuel were carried in six main fuselage tanks. The tanks numbered one through six moved forward to aft (back) tank 6B It could hold 7,020 pounds of gravity-fed fuel and two tank sumps. This was also called the “doghouse” and was located in the extreme back portion of the fuselage.

These are just a few interesting facts found by reading Rich Graham’s “SR 71 Revealed the Inside Story.” This book was published in 1996 before some of the facts about the SR-71 became unclassified.

Fuel was the lifeblood of the world’s fastest manned aircraft.

Check out the Habubrats SR-71 and Born into the Wilde Blue Yonder Facebook pages for further Blackbird photos and stories.

Photo by NASA and U.S. Air Force

‘My RSO had given him “the bird” with his middle finger: I lit the afterburners and left that Mirage standing still. Two minutes later, we were crossing the Channel,’ Lt. Colonel William Burk Jr., former SR-71 Blackbird pilot

The Lockheed A-12 and YF-12A aircraft served as the basis for the development of the SR-71, also referred to as the “Blackbird,” or long-range, advanced strategic reconnaissance aircraft. The 4200th (later 9th) Strategic Reconnaissance Wing at Beale Air Force Base, California, received the first SR-71 to begin service in January 1966. The first SR-71 flight occurred on December 22, 1964. On January 26, 1990, the US Air Force (USAF) retired its fleet of SR-71 aircraft.

For almost two decades, the SR-71 held the record for being the fastest and highest-flying operational aircraft in the world. It could cover 100,000 square miles of the Earth’s surface per hour from 80,000 feet.

Lt. Colonel William Burk Jr. has some of the most interesting stories about flying the SR-71. He talks of a mission he flew over Lebanon in 1982; according to SR-71 pilot Stormy Boudreaux, Tom Henichek was Burk’s RSO for that mission

The story appears in both this post’s video and Ben Rich’s book Skunk Works.

‘In the fall of ’82, I flew from Mildenhall on a mission over Lebanon in response to the Marine barracks bombing. President Reagan ordered photo coverage of all the terrorist bases in the region. The French refused to allow us to overfly, so our mission profile was to refuel off the south coast of England, a Mach 3 cruise leg down the coast of Portugal and Spain, a left turn through the Straits of Gibraltar, refuel in the Western Mediterranean, a right turn into Lebanon and fly right down Main Street Beirut, exit along the southern Mediterranean with another refueling over Malta, supersonic back out of the straits, and return to England. Because Syria had a Soviet SA-5 missile system just west of Damascus that we would be penetrating (we were unsure of Syria’s intentions in this conflict), we programmed to fly above 80,000 feet and at Mach 3+ to be on the safe side, knowing that this advanced missile had the range and speed to nail us.

‘As we entered Lebanon’s airspace, my Recon Systems Officer in the rear cockpit informed me that our defensive systems display showed we were being tracked by that SA-5. About 15 seconds later, we got a warning of active guidance signals from the SA-5 site. We couldn’t tell whether there was an actual launch or the missile was still on the rails, but they were actively tracking us. We didn’t waste any time wondering, but climbed and pushed that throttle, and said a couple of “Hail Kellys.”

‘We completed our pass over Beirut and turned toward Malta, when I got a warning low-oil-pressure light on my right engine. Even though the engine was running fine, I slowed down, lowered our altitude, and made a direct line for England. We decided to cross France without clearance instead of going the roundabout way.

‘We made it almost across, when I looked out the left window and saw a French Mirage III sitting ten feet off my left wing. He came up on our frequency and asked us for our Diplomatic Clearance Number. I had no idea what he was talking about, so I told him to stand by. I asked my backseater, who said, “Don’t worry about it. I just gave it to him.” What he had given him was “the bird” with his middle finger. I lit the afterburners and left that Mirage standing still. Two minutes later, we were crossing the Channel.’

Check out Habubrats SR-71 and Born into the Wilde Blue Yonder Facebook pages for further Blackbird photos and stories.

Photo by U.S. Air Force and French Air Force Via FAST Museum Twitter Account

‘One of the real highlights of flying above Mach 3 and above 80,000 feet is nobody is up there with you,’ David Peters, former SR-71 Blackbird pilot

The SR-71 Blackbird is the only reconnaissance aircraft in history to have operated in more hostile airspace and with such complete impunity. Air-breathing engines powering this aircraft are the fastest in the world. The Blackbird represented the highest point in aviation technology development during the Cold War due to its performance and operational accomplishments.

The SR-71 Blackbird gathered intelligence in some of the world’s most hostile environments during its 24 years of operation. The Blackbird is still the only US Air Force (USAF) aircraft to never lose a crew member, either in the air or on the ground, having successfully avoided all 1,000 missiles fired at it.

The Blackbird was built for flying at high speeds and altitudes; in fact, it could cover 100,000 square miles of Earth’s surface per hour from 80,000 feet. It was very hard for any surface-to-air (SAM) missile or fighter jet in use at the time to get a radar lock on it.

Therefore, it is untrue that the SR-71’s flight was discontinued due to fears that it might be intercepted by Soviet MiGs or jet fighters that were then serving with neutral nations in the Baltic. There were many precautions taken to keep the Blackbird safe from being fired, some of which are still classified and hence cannot be described in detail.

This statement is confirmed by David Peters, a former SR-71 pilot;

‘We were allowed 45 degrees of bank for a designated high bank turn. Radius is about 60 miles at 3.2. But your change of heading is pretty rapid you are just covering a lot of ground and air doing it. Most people don’t understand the dynamics. We were not going to outmaneuver much of anything. What matters is the proximity, to start with. The speed and range of the protagonist. One of the real highlights of flying above Mach 3 and above 80,000 feet is nobody is up there with you. They have to see you (radar) first. How far away is significant because we are not just larking along. If you are talking surface-to-air missiles, how long does it take to launch get to 80,000 feet? How long does it take, and how close does it have to get to be able to maneuver if we are not going straight ahead? Very few missiles could go far enough to make up 36 or more miles per minute.

‘All this is not taking any consideration of our ECM capability.’

Peters concludes;

‘The bottom line is the only surface-to-air missile that had any chance at all was the SA-10 [SA-10 Grumble, the NATO reporting name of the S-300 Soviet SAM system] if it was nuclear. That would allow them to fire it out ahead of us with an air burst at altitude, which we could possibly not circumvent. Airborne I.e. interceptors, none had any chance, what so ever.’

Check out the Habubrats SR-71 and Born into the Wilde Blue Yonder Facebook pages for further Blackbird photos and stories.

Photo by Russian Ministry of Defence and Lockheed Martin

No story on the SR-71 would be complete without an understanding and appreciation of just how valuable the KC-135Q model tankers and their crews were to the successful and safe completion of every mission

The Lockheed A-12 and YF-12A aircraft served as the basis for the development of the SR-71, also referred to as the “Blackbird” or long-range, advanced strategic reconnaissance aircraft. The 4200th (later 9th) Strategic Reconnaissance Wing at Beale Air Force Base, California, received the first SR-71 to begin service in January 1966. The first SR-71 flight occurred on December 22, 1964. On January 26, 1990, the US Air Force retired its entire fleet of SR-71s.

For almost two decades, the SR-71 held the record for being the fastest and highest-flying operational aircraft in the world. It could cover 100,000 square miles of the Earth’s surface per hour from 80,000 feet. Two world records for its class were set on July 28, 1976, by an SR-71: an absolute speed record of 2,193.167 mph and an absolute altitude record of 85,068.997 feet.

If it weren’t for air refueling, the SR-71’s range would be relatively limited—roughly 2,000 NM. The aircraft’s range was increased by several air refuelings to the crew’s maximum endurance. Many missions have gone above 12,000 NM. The SR-71 and KC-135Q tankers’ forward basing allowed for increased overall efficiency, shorter range, shorter length missions, and faster reaction times.

There were various ways in which KC-135Q crews and their aircraft were different from other Air Force units. Actually, their boom operators were the only ones qualified to refuel the SR-71, and their aircrews were the only ones certified in Blackbird’s unique radio-silent rendezvous procedures. The Q-model tankers could move JP-4 and JP-7 fuel between different tanks because of special plumbing between the tanks.

They could use JP-4 or JP-7 fuel in their engine. If the SR-71 touched down in an area without JP-7 fuel, the Q-model tankers would fly in with the fuel and refill the aircraft using ground-based transfer hoses. One of the biggest benefits of flying Q-model tankers was that, unlike other SAC tanker crews, their personnel did not have to be on constant alert.

No story on the SR-71 would be complete without an understanding and appreciation of just how valuable the KC-135Q model tankers and their crews were to the successful and safe completion of every mission.

Most SR-71’s operational sorties started off with a refueling after takeoff.

“Many people believe we refueled after takeoff because the aircraft leaked fuel so profusely that we needed to fuel up quickly,” says Col. Richard H. Graham, a former Blackbird pilot, in his book SR-71 The Complete Illustrated History of THE BLACKBIRD The World’s Highest, Fastest Plane. “We had to refuel right after takeoff for only one reason, and it wasn’t because we leaked JP-7 fuel on the ground. Yes, the plane does leak fuel, but not enough to require refueling after takeoff.

“The JP-7 fuel reaches temperatures well over 300 degrees F. during Mach 3 cruise, making the fumes in each of the six fuel tanks very volatile and potentially explosive. The metal skin of the aircraft approaches 400 degrees F., adding to the volatility of the fuel inside the tanks. One of our aircraft limitations was a maximum speed of Mach 2.6 without an inert atmosphere inside the fuel tanks.

“The aircraft had three liquid nitrogen Dewar flasks containing 260 liters of liquid nitrogen, located in the nose wheel well. The only way to ensure 100 percent inert atmosphere in each fuel tank was to refuel the plane in flight completely full of JP-7, allowing ambient air in each fuel tank to vent overboard. Once full of fuel, gaseous nitrogen would now dominate each fuel tank’s empty space above as it burned off JP-7. The nitrogen gas pressurized each fuel tank to 1.5 psi above ambient pressure and inerts the space above the heated fuel to prevent autogenous ignition. This is why we refueled after takeoff. Then we could safely accelerate beyond Mach 2.6.”

Graham concludes:

“There was one other way of achieving tank inerting, called a “Yo-Yo,” but this was a maintenance nightmare. A few of our missions required the SR-71 to accelerate to Mach 3+ right after takeoff with a 65,000-pound fuel load. The Yo-Yo procedure had the crew chief completely refuel the plane to full tanks of 80,000 pounds of fuel. Then, with the nitrogen pressurization system working, they de-fueled 15,000 pounds of JP-7, ending up with a 65,000 pound fuel load and a plane that was capable of going immediately to Mach 3+.”

Photo by U.S. Air Force and Tony Landis Lockheed

‘“Beautiful, beautiful, come back and do another one,” the tower controller said,’ Maury Rosenberg, SR-71 Blackbird pilot

The Lockheed A-12 and YF-12A aircraft served as the foundation for the development of the SR-71, also referred to as the “Blackbird” or long-range, advanced strategic reconnaissance aircraft.

The SR-71 Blackbird is the only reconnaissance aircraft in history to have operated in more hostile airspace and with such complete impunity. It is the fastest aircraft propelled by air-breathing engines. The Blackbird represented the highest point in aviation technology development during the Cold War due to its performance and operational achievements.

The Blackbird was built to reach altitudes of up to 85,000 feet and cruise at “Mach 3+,” three times faster than the speed of sound, or more than 2,200 miles per hour.

The following tape transcription, which was recorded in 2018 at the Western Museum of Flight, reports SR-71 Pilot Maury Rosenberg discussing the one occasion when he chose to ask for a “fly-by” over the Sacramento airport while returning to Beale Air Force Base (AFB), where he was supposed to land.

The request was eagerly approved by the air tower crew, who wanted him to fly the SR-71 “down the ramp” (much closer to the tower and other buildings).

Rosenberg recalls:

‘I think it was the 1982 or 83 Toronto Airshow. I was a participant; we took an SR-71 and three crews went. One crew flew it in. One crew flew on the second-day airshow. And the third crew, which was myself, flew just a couple of flybys on the third day of the airshow and then actually flew the aircraft back to Beale Air Force Base. So when I came back into the Sacramento area and I was descending down to land at Beale, we had a lot of fuel. We had to work on the holiday, and I asked the backseater You want to make an approach at Sac Metro? And he said Can we do that? And I said Why not?

‘So, when we got over to approach control I asked if Sac Metro was available for an approach and they said they’d switch this over to Sac Metro and they cleared us for an approach. So, as we were coming down final and we had configured the airplane with the gear down and we’re about two miles out on final, they switched us over to tower.

‘I asked the tower Would you like a flyby down the runway or down the ramp? The guy said Down the ramp! When I said okay, I sucked the gear up, pushed the power up. We started heading towards the ramp, towards the tower. As we were approaching it, I rolled the plane up away from the tower and lit the afterburners. We went around and made a pass. The tower controller said, “Beautiful, beautiful, come back and do another one”. I said I better not, I’m gonna go to Beale. So, we went back to Beale and we landed.

‘As I mentioned it was a holiday weekend and Colonel Lonnie met us when we pulled in the hangar after we landed which was the normal procedure. I thought well that’s nice that he came out. As I came down the ladder from the aircraft, he looked at me and he said Maury, do we have any regulations that say we can’t make approaches at Sacramento Airport? I said No sir.
I want one on my desk at seven o’clock tomorrow morning.

‘Now there’s a continuation to this story. I retired in 87 and flew with United Airlines. I was a Boeing 767 co-pilot and in 87, I think it was either the fall of 87 or the winter of 88 right after the New Year, I was flying a 767 from Washington DC to San Francisco and an air traffic controller wanted to know if they could ride in the cockpit. The captain of the plane signed it off. So, this young lady was the air traffic controller. I was flying, it was my leg from DC to San Francisco.

‘We’re flying and he’s just talking to her halfway across the country and at some point, he asked her how long she’d worked at San Francisco Airport. She hadn’t been there that long, she said she used to work at Sac Metro. I looked over my shoulder at this young lady and I said Were you working Sac Metro in 1982? She looked at me and she said yeah, I was, why do you ask? I said Were you working the tower when the SR-71 buzzed it? Oh yeah, I was how did you know that and I told her it was me and she started laughing. She said you scared the hell out of people, there were people in the terminal that dived to the ground. They thought the airplane was going to hit the turf.’

Check out the Habubrats SR-71 and Born into the Wilde Blue Yonder Facebook pages for awesome Blackbird photos and stories.

Photo by Unknown