How slow can an SR-71 BLACKBIRD fly?

[sc_rufctr]

A-12 Oxcart—father of the SR-71 Blackbird

http://sploid.gizmodo.com/the-story-of-the-ultrasecret-a-12-oxcart-father-of-the-1684070908

[sc_rufctr]

[scottmandue]

We have a trainer on display here at the science museum, they disassemble it for shipping.

[rcooled]

I saw this one at the Udvar-Hazy annex of the Smithsonian National Air & Space museum out at Dulles airport. Very cool place to visit if you're in the D.C. area.

[red-beard]

[rick-l]

Originally Posted by Embraer

I work on the grounds of plant 42. you still see amazing things everyday here. U2's taking off, B1's and B2's doing pattern work. You'd be surprised what takes off out of here, once the cover of night sets in.

When I was there in the late 70's (when they made L-1011s there) it was also a training area for a couple of airlines. From the office it was interesting to watch DC-10s bounce in on one wheel and take off with engine failure yaw.

[svandamme]

Originally Posted by GH85Carrera

Here is another video that is oven an hour from the same guy.

555th , Ubon, he probably flew under Robin Olds who was wing commander there of the 8th wing.. Look up Operation Bolo.

[sc_rufctr]

Originally Posted by red-beard

Brian is a legend. His story is truly inspirational. (& there go any excuses I ever had about anything)

[svandamme]

Originally Posted by red-beard

I read that story before, and it was brilliant then, hearing it told even better.

[rick-l]

Here is a fighter version (production 3)

I worked with a guy associated with the SR71 who said to get back to the US from Vietnam they would point the nose up, climb until they flamed out, drift through low space until the engine would relight and repeat. Does this sound feasible?

[svandamme]

Originally Posted by rick-l

Here is a fighter version (production 3)

I worked with a guy associated with the SR71 who said to get back to the US from Vietnam they would point the nose up, climb until they flamed out, drift through low space until the engine would relight and repeat. Does this sound feasible?

Considering the lack of control thrusters in an SR71 I would have to say bs.
They could come back down from space into thin air, ass over head, spin and black out and be a hole in the ground by the time they wake up.

They did that with F104's, Yeager did that.. It had control thrusters.

https://en.wikipedia.org/wiki/Lockheed_NF-104A#Reaction_Control_System_2

[Scott Douglas]

It's well worth the time to watch the videos linked here in this post.
I just finished the hour long one. Very informative and well done.

The SR's that overflew Vietnam flew out of Okinawa, not the US.

[svandamme]

Originally Posted by Scott Douglas

It's well worth the time to watch the videos linked here in this post.
I just finished the hour long one. Very informative and well done.

The SR's that overflew Vietnam flew out of Okinawa, not the US.

Most indeed from Kadena, but not all of the Vietnam missions
Some flew out of Beale, some even out of UK

[svandamme]

Another reason why the zoom climb to space story does not add up, is that the fuel has an extremely high flashpoint, and need special chemicals to fire the thing up.

So would anybody risk flaming out both engines if those engines are so hard to ignite.
With such an exclusive, expensive plane?
doubt it.

[sammyg2]

From what little i know of these planes, at the speed they flew the tiniest uncontrolled change any of the three axes could have been disastrous.
If an engine flamed out at mach 3 I'd be surprised if the plane didn't disintegrate.

[sammyg2]

The incredible story of a lucky SR-71 pilot who survived to a Blackbird disintegration at Mach 3+


Built as a strategic reconnaissance aircraft able to fly at 88,000 feet and Mach 3, the iconic Lockheed SR-71 required aircrews to wear a special silver pressure suit to ensure their safety. This proved to be much useful during the time, as the aircraft experienced several accidents at very high speeds and altitudes during its test flights.

The protection provided by these suits was put to test on Jan. 25, 1966 when Blackbird tail number 952 disintegrated mid-air during a systems evaluation flight. The mission was intended to investigate procedures designed to reduce trim drag and improve high Mach cruise performance while the center of gravity (CG) was located further aft than normal, reducing the Blackbird’s longitudinal stability.

The SR-71 was driven by Bill Weaver with a Lockheed flight test specialist, Jim Zwayer in the back seat and it took off from Edwards AFB at 11:20 am . They refueled from a KC-135, accelerated to Mach 3.2 and climbed to 78,000 feet, which was their initial cruise altitude.

During a programmed thirty-five-degree bank right turn they experienced an “inlet unstart” that caused the immediate unstart on the right J-58 engine, forcing the aircraft to roll further right and start to pitch up. An inlet unstart happened when a shock wave was rapidly ejected back outside the inlet. When an inlet unstart occurred a device called the cross-tie system was enabled to minimize the extreme rolling and yaw of the aircraft and to prevent the good inlet from unstarting. At the same time the cross-tie system also restarted the good engine. As Weaver himself told to former Blackbird pilot Col. Richard H. Graham in his book, “SR-71 The Complete Illustrated History of THE BLACKBIRD The World’s Highest, Fastest Plane”: “I jammed the control stick as far left and forward as it would go. No response. I instantly knew we were in for a wild ride.”

Since the chances to survive an ejection at Mach 3.18 and 78,000 feet weren’t very good, Weaver and Zwayer decided to stay with the aircraft to restore control until they reached a lower speed and altitude, but the cumulative effects of system malfunctions exceeded flight control authority. Everything seemed to unfold in slow motion, even if the time from event onset to catastrophic departure from controlled flight was only two to three seconds.

Weaver recalls that he was “still trying to communicate with Jim, I blacked out, succumbing to extremely high g-forces. Then the SR-71 literally disintegrated around us.”

Weaver struggled to realize what was really happening. “I could not have survived what had just happened. I must be dead. As full awareness took hold, I realized I was not dead. But somehow I had separated from the airplane. I had no idea how this could have happened; I hadn’t initiated an ejection. The sound of rushing air and what sounded like straps flapping in the wind confirmed I was falling, but I couldn’t see anything. My pressure suit’s face plate had frozen over and I was staring at a layer of ice.”

It was at that point that the pressure suit proved to be very effective protection for Weaver. In fact, once it was inflated, an emergency oxygen cylinder in the seat kit attached to the parachute harness was functioning. It not only supplied breathing oxygen, but also pressurized the suit, preventing Weaver’s blood from boiling at the extremely high altitude. In this way the suit’s pressurization had also provided physical protection from intense buffeting and g-forces. That inflated suit had become like a tiny escape capsule.

Another system conceived to safeguard the Blackbird aircrew during the bailout procedure was the SR-71’s parachute system. To prevent body tumbling motions and physical injury due to the centrifugal forces it was designed to automatically deploy a small-diameter stabilizing parachute shortly after ejection and seat separation.

Since Weaver had not intentionally activated the ejection sequence, he thought that stabilizing chute might not have deployed. But he quickly determined he was falling vertically and not tumbling, meaning that the little parachute had deployed and was doing its job. The next concern was for the main parachute, which was designed to open automatically at 15,000 feet, but again he had no assurance the automatic-opening function would work. So Weaver decided to open the faceplate, to estimate his height above the ground but as he reached for the faceplate, he felt the reassuring sudden deceleration of main parachute deployment.

After landing, Weaver was rescued by Albert Mitchell Sr., owner of a ranch in northeastern New Mexico, who helped him with the chute, then reached Zwayer who had landed not far away, with his own Hughes helicopter. Mitchell returned few minutes later reporting that Zwayer was dead: in fact he had suffered a broken neck during the aircraft’s disintegration and was killed almost instantly. Moreover Mitchell said that his ranch foreman would watch over Zwayer’s body until the arrival of the authorities and he flew Weaver to the Tucumcari hospital.

Investigation of the incident determined that the nose section of the Blackbird had broken off aft of the rear cockpit and crashed ten miles from the main wreckage. The resultant very high g-forces had literally ripped Weaver and Zwayer from the airplane. After this crash, testing with the CG aft of normal limits was discontinued, and trim-drag issues were resolved via aerodynamic means. Moreover the inlet control system was improved and the inlet unstarts almost stopped with the development of the Digital Automatic Flight and Inlet Control System.

https://theaviationist.com/2015/03/17/sr-71-mid-air-disintegration/

[sammyg2]

This is a great read:

[switch to pilot report mode]

I was running about 15 minutes late for a 1300 hours scheduled takeoff. Engine runup on the runway, full military power with toe brakes applied, was normal. Engine rpm came up, at which point I released the brakes and lifted the throttle past the gate into afterburner. The burners kicked in with the usual thump [you actually feel and hear it in the sim]. All systems were nominal as I rolled down the runway. At 175 knots I rotated the aircraft. I left the ground at 210 knots and began my climbout.

The first thing I did after takeoff was raise the gear. At this point, my nose was a bit high, as KEAS was not climbing. I reduced the angle of climb to 15 degrees and the airspeed increased appropriately. I took a gentle turn to the West and continued around Palmdale, settling eventually on an Easterly course towards Las Vegas, NV.

A few minutes after takeoff I executed (poorly :-) a dip to push through Mach 1. Airspeed increased rapidly (as did altitude) after the A/C went supersonic. Flight time from takeoff to Las Vegas was 12 minutes. I was over Mach 2 when I executed a 90 degree turn to the North after passing Las Vegas. I trimmed the aircraft and engaged roll and pitch autopilots, maintain KEAS autopilot, and the autonavigation system. At that point the aircraft continued a 10 degree climb to FL 800 (80,000 feet). The normal flight profile calls for a KEAS of approximately 450.

At approximately 74,000 feet and Mach 3.1, somewhere over Colorado, I believe, I experienced an unstart in the left engine. It was a relatively gentle unstart, and I was able to control the fast roll to the out engine with relative ease. The computer immediately advanced the spike to spike station 0 and reaquired the shock wave. The engine was operating normally seconds after the unstart. The SR-71 yaws and rolls immediately to the out engine side when experincing an unstart. This requires quick response from the pilot. At these speeds, it is important not to pull the nose up while recovering from an unstart, as the plane will break in half from aerodynamic forces at an alpha (angle of attack) of 8 degrees.

I continued North while climbing. During the time I approached the Canadian border, I experienced three more unstarts, two in the port engine and one in the starboard engine (sympathetic unstart during a port engine unstart). Each time, the autopilot stayed engaged and the computers reset the inlet spikes. The only pilot input, other than maintaining the aircraft's attitude (which requires a bit of work, I'll tell ya), is to rearm the derich system.

Just before reaching the Canadian border, I experienced a violent unstart in the port engine (strong enough to bash my head solidly against the cockpit window). The unstarts are accompanied by an unsettlingly loud "bam" from aft in the aircraft, followed by a rapid roll. There is a laser-projected artificial horizon across the front instrument panel. This is very convenient, because during an unstart the pilot needs to pay attention to the attitude indicator, the CIP guage, and the spike position guages. It is distracting to look from the lower-left front panel (CIP and spike guages) to the ADI at the top-center panel. The laser artificial horizon allows the pilot to look at the spike controls while recovering the A/C's attitude with peripheral vision.

As the computers were attempting to recover from the unstart, the left nacelle fire indicator lit. Shortly thereafter, I lost the port side turbine. At that point, I initiated a gentle westerly turn to return to base and pulled the port throttle to idle. The aircraft at this point (about Mach 3 and 78,000 feet) was difficult to control, and was rolling from side to side as I attempted to maintain control. Over Idaho, in the middle of my turnaround, the warning light for left generator lit, indicating that the port side generator had failed.

As I continued my turn, I experienced an unstart in the starboard engine. Much to my concern, this was followed almost immediately by a right side turbine failure and right nacelle fire. I reduced the throttle and brought the nose down to maintain approximately 368 KEAS. The SR-71 does not make an impressive glider, even at Mach 3, and I began rapidly losing altitude. Unfortunately, at that point I lost the right side generator, and along with it, the majority of the cockpit instrumentation. The only instruments I had in my glider at that point was the TDI, backup attitude indicator, and a compass. Losing altitude, airspeed, and control (the stability augmentation computers were lost along with the right side generator) rapidly, I "ejected" at 47,000 feet and mach 1.2, somewhere over southern Utah.

[end pilot report]



I climbed out and my jaw muscles were sore from clenching my teeth, my head hurt from the unstart that slapped me into the cockpit window, and I was dripping sweat. I was also in heaven, just from the opportunity to fly the simulator. What an experience!

gotcha.

Flying the SR-71...In a Simulator

[javadog]

The Vietnam story is crap, as they carried about 80,000 pounds of fuel and that gave them a range of a littlre over 3,300 miles. No way they could have made it from Vietnam to the US in that way. They did occasional long trips but they refuelled a bunch. There was always a limit to how far they went, at they only carried enough TEB to light the engines (or engage the afterburners) 16 times. Not only did they use a shot of TEB when lighting the engines off, they used a shot every time they moved the throttles to the afterburner position. Considering they cruised with the afterburners lit, this meant that every time they got off of a tanker, they had to light the burners again. There was another way to light the burners but i don't think it would have re-lit a flamed out engine.

Inlet unstarts were a problem and they could result in the afterburners flaming out. One other consideration is that they used the fuel as hydraulic fluid for some of the systems, so running out of fuel was not an option.

They often had inlet unstarts at high mach numbers that were bad enough to bang the pilots head off of the side of the canopy. Aileron authority was inadequate above 75,000 feet to deal with really large problems (an unstart caused yaw, pitch and roll problems immediately) so these planes were flown very carefully and precisely at high speeds and altitudes. I don't know that they've ever declassified the max altitudes they reached but they were nowhere near what they got out of the NF-104A.

JR

[sammyg2]

Wiki:
It (NF-104A) quickly established a new unofficial altitude record of 118,860 feet (36,230 m) and surpassed this on 6 December 1963 by achieving an altitude of 120,800 feet (36,800 m).

[Don Ro]

Originally Posted by Craig T

You can count on that. The SR-71 was around for over a decade before the public even knew it existed...And was no doubt the source of many a nighttime UFO reporting.

As I recall, LBJ announced the existence of the YF12A to the public in Feb. '64.

I attended an electronics class for two weeks back in '65 at Beale AFB (CA) where there was a squadron of them. Never was able to get too close, however. Just looking at them took my breath away.
Interesting stories from the maintenance guys.