• Welcome to SVTPerformance!

SR-71 Blackbird fun facts

Discussion in 'Road Side Pub' started by James Snover, Oct 16, 2019.

  1. James Snover

    James Snover The Ill-Advised Physics Amplification Co Established Member

    Messages:
    8,299
    Joined:
    Jan 23, 2008
    Location:
    Cypress
    The Blackbird predated inertial navigation and GPS. And it went too fast for LORAN and other conventional aviation nav aids. And at the speeds it traveled, a few tenths of a degree of error in the flight path meant hundreds of miles of error at the point you needed the cameras to roll, at the point at which you were supposed to meet up with the tanker, etc. All very bad things.

    To solve it, Lockheed developed an automated star-tracking telescope system. It had enough memory for something like 15 constellations, and it could see the brightest stars even in full daylight. It worked, very well. It had a few drawbacks, though. Sometimes, if there were any small holes in the canopy of the covered revetments they housed the Blackbirds in prior to takeoff, as they "spun up" the star tracking system, it would see the small holes, interpret them as a constellation, lock on, and start throwing up all sorts of errors. BNefore it even released the brakes for taxi out to the runway.

    There is a myth that the Blackbird could not takeoff with full tanks of fuel. Not true, and on several missions, that was exactly what they did. They reason they didn't was that a full load of fuel increased the weight on the wheels by another 100,000lbs. This increased your takeoff run, it cut the "takeoff abort point" by a huge margin, because the brakes just couldn't slow all that down, and if they lost an engine on takeoff, they're options were severely reduced with regard to doing a go-around and coming in for landing. One engine, at full fuel load, even on full afterburner, could not maintain level flight with the landing gear down. It was far better to take off with minimal fuel, heat up, then meet up with a tanker and top off.

    The most critical time element in a Blackbird mission was take-off time. Ironically, despite being the fastest aircraft in the skies, the Blackbird could not make up for lost time in the air. Because it's cruise speed WAS it's max speed, an oddity in the aviation world. There are unsubstantiated reports of Blackbirds temporarily exceeding Mach 3.2 and flying higher than 85,000 feet, but it was only to outrun missiles. And the folks telling me these things usually then say, "It'd do it, but it wasn't happy doing it." Whereas it would happily cruise all day long at Mach 3.2 at 80,000-85,000 feet. In any event, she couldn't go much faster than 3.2 for long before important things, like the engines, began to melt.

    They couldn't make the old girl fly truly straight and level. The best the could get was a constant slight climb and descent. So if they were aiming for 80,000 feet altitude, they'd set it up for a slow climb to 85,000, then a slow descent to 75,000, repeat as needed.
     
    roadracer247, jeffh81, murse and 12 others like this.
  2. lexustech48

    lexustech48 Ghost Editor-In-Chief Premium Member Established Member

    Messages:
    5,915
    Joined:
    Sep 29, 2014
    Location:
    Arizona
    Truly an amazing machine. I have to imagine that if we did this in the 50's, what in the hell are they up to now?
     
  3. blk02edge

    blk02edge Well-Known Member Established Member

    Messages:
    5,288
    Joined:
    Feb 20, 2008
    Location:
    BC
    Prolly those pesky drones the airforce is on about lately
     
    jeffh81, 03Sssnake and lexustech48 like this.
  4. scott_0

    scott_0 Well-Known Member Established Member

    Messages:
    4,171
    Joined:
    Jul 30, 2011
    Location:
    oxford, pa
    absolutely love this amazing piece of art that is the sr71


    Sent from my iPhone using Tapatalk
     
  5. Weather Man

    Weather Man Persistance Is A Bitch Established Member

    Messages:
    13,951
    Joined:
    May 18, 2012
    Location:
    MN
    Ramjet and scramjet tech.
     
  6. 7998

    7998 Well-Known Member Established Member

    Messages:
    1,604
    Joined:
    Mar 12, 2008
    Location:
    PA
    One of my favorite aircraft. What amazes me about the SR-71 and the Space program is what they could accomplish with the resources they had available. It seems all of our modern technology was developed within this period.
    @James Snover I'm curious, what is your relation to the SR-71?
     
    03Sssnake likes this.
  7. Papaw

    Papaw Well-Known Member Established Member

    Messages:
    501
    Joined:
    May 12, 2013
    Location:
    West Coast
    Wonder how fast it would go with a 150 shot.
     
    jeffh81, lexustech48 and john11gt like this.
  8. Double"O"

    Double"O" N2S come get some Established Member

    Messages:
    14,635
    Joined:
    May 12, 2003
    Location:
    PA
    Low 10s with a tire and driver mod
     
  9. AustinJ427

    AustinJ427 Well-Known Member Established Member Beer Money Bros.

    Messages:
    4,876
    Joined:
    Jan 29, 2014
    Location:
    Colorado
    More than you'd ever expect.

    What do you think the SR is for?

    SnoveR
     
    7998 likes this.
  10. Rubenk

    Rubenk Wasn't me. Established Member

    Messages:
    4,924
    Joined:
    Sep 23, 2007
    Location:
    KCMO
    Always love SR-71 facts.

    Did you say 100,000 lbs extra for just a full load of FUEL?!
     
  11. James Snover

    James Snover The Ill-Advised Physics Amplification Co Established Member

    Messages:
    8,299
    Joined:
    Jan 23, 2008
    Location:
    Cypress
    Don't I wish!


    Sent from my iPad using the svtperformance.com mobile app
     
  12. James Snover

    James Snover The Ill-Advised Physics Amplification Co Established Member

    Messages:
    8,299
    Joined:
    Jan 23, 2008
    Location:
    Cypress
    None at all. Just over the last forty years I have collected every bit of info on it I can find. Talked to pilots and crew. Bought every book on it I can find.

    By far, the best single book on the Blackbird is Ben Rich's autobiography, "Skunkworks." He is the guy who designed the inlets, and designed the aircraft's thermodynamics. He was Kelly Johnson's right-hand man.

    That book has so much info on the design and building of the old girl I was surprised it was allowed to be published.

    Rich Graham has written a whole series of books on the Blackbird. He was a pilot of the bird, and then he was in charge of the whole program.


    Sent from my iPad using the svtperformance.com mobile app
     
    BOOGIE MAN and 7998 like this.
  13. CobraBob

    CobraBob Authorized Vendor Premium Member Established Member

    Messages:
    89,101
    Joined:
    Nov 17, 2002
    Location:
    Cheshire, CT
    Nice write-up James. I've always been fascinated with the Blackbird. Pretty much everyone is.
     
  14. ON D BIT

    ON D BIT Finish First Established Member

    Messages:
    14,462
    Joined:
    Jul 7, 2003
    Location:
    Currently in Sonoma County
    Love the Entire Skunkworks team, my grandpa was a part of this team and helped design build the SR71. Sadly he past before I knew anything about his work or this plane.
     
  15. James Snover

    James Snover The Ill-Advised Physics Amplification Co Established Member

    Messages:
    8,299
    Joined:
    Jan 23, 2008
    Location:
    Cypress
    Yep. Distributed throughout various tanks to control the aircraft's center of gravity vs. it's center of lift. By shifting the fuel around, they could trim it out without having to deflect the control surfaces, which would have added a lot of drag. The center of gravity had to be watched constantly because it changes with the speed of the aircraft, too far forward or aft, and at the veary least your fuel consumption goes through the roof, and at the very worst, the plane becomes unflyable and destroys itself.

    There was a container of liquid nitrogen onboard, as the fuel was consumed, the tanks were filled with liquid nitrogen so there couldn't be a fire.

    The fuel was notoriously un-inflammable. You could fill a bucket with it, drop a match in it, and the match would go out. It absolutely would not catch on fire. So they also used the fuel as coolant, to pull heat away from the hottest parts of the airframe. Thsi alo preheated the fuel, so when it did hit the combustion chambers, it would burn.

    On takeoff, though, they had to add a shot of TEB, tetra-ethyl-borane, a chemical compound so nasty it instantly burst into flame on contact with air. That would at least allow the fuel to ignite in cold combustion chambers. Also had to have a shot of TEB when they lit the afterburners, if they had been shut down. The throttle had a counter on it: it displayed the number of shots of TEB available, it counted down from 50. When you ran out of TEB, you could not relight the afterburners. And if the engines flamed out, and you had no TEB, you were very quickly going to be back on the ground because you could not restart the engines without it. They were difficult enough to restart, even with it.

    It took up to 25 minutes to refuel once they found the tanker. Oddly, only one half of the windshield had a defroster, and at 30,000 or so feet at -40F, the Blackbird cooled off fast, and the windshield frosted over almost immediately.

    EDIT: The fuel was notoriously UN-inflammable was what I meant to say. Corrected it up above, but just so everyone knows: I mis-typed it, originally. No doubt some form of Russian interference, I'm certain ...
     
    Last edited: Oct 17, 2019
    jeffh81, 7998, SHIFTYBUSINESS and 2 others like this.
  16. James Snover

    James Snover The Ill-Advised Physics Amplification Co Established Member

    Messages:
    8,299
    Joined:
    Jan 23, 2008
    Location:
    Cypress
    Still that is awesome to have a family connection to Blackbird!
     
    ON D BIT and CPT RR like this.
  17. 03cobra#694

    03cobra#694 Want to play a game? Staff Member Super Moderator

    Messages:
    49,774
    Joined:
    Aug 12, 2008
    Location:
    SW FL.
    Still amazing to me in that time they could do this stuff. I’m actually scared what we have now. I’d love to know though.
     
    DSG2003Mach1 and BOOGIE MAN like this.
  18. HillbillyHotRod

    HillbillyHotRod Hooligan rabble rouser Established Member

    Messages:
    3,824
    Joined:
    Jan 9, 2014
    Location:
    Ozarks of Arkansas
    Strategic Reconnaissance?
     
  19. coposrv

    coposrv Well-Known Member Established Member

    Messages:
    4,481
    Joined:
    Sep 4, 2007
    Location:
    boston
    Probably past that now. The give away of a pulse engine, the donuts on a rope contrail were seen as far back as the 80’s.


    Sent from my iPhone using the svtperformance.com mobile app
     
    BOOGIE MAN likes this.
  20. James Snover

    James Snover The Ill-Advised Physics Amplification Co Established Member

    Messages:
    8,299
    Joined:
    Jan 23, 2008
    Location:
    Cypress
    Yep. And, even more interestingly, until recently, tracked by ground seismometers looking for earthquakes.
     
    BOOGIE MAN likes this.

Share This Page