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Science question of the day: Why was the SR-71 Blackbird painted black?

Discussion in 'Road Side Pub' started by James Snover, Sep 15, 2019.

  1. James Snover

    James Snover The Ill-Advised Physics Amplification Co Established Member

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    When the SR-71 was was under development they had a weight problem. Even using Titanium everywhere they could, even leaving out every last possible thing that contributed nothing but added weight, they were pushing the weight limit to the very edge.

    Kelly Johnson, lead engineer of Project Oxcart, got so desperate he offered his engineers, mechanics, and assembly line folks, up to a hundred dollars for every pound they could cut from the design.

    In the midst of this, Johnson's right-hand man, Ben Rich, made a suggestion: paint it black. That might not sound like much, but on an aircraft that size, with the type of paint they used, it was going to add 1,100 pounds of weight. When Johnson was tearing his hair out trying to save pounds, his top guy was talking about adding 1,100 pounds in one fell swoop! Just to paint it black.

    Why?
     
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  2. gimmie11s

    gimmie11s Handlebar mustaches... PSSHHH! Established Member Established Member

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    To reduce the internal temp of the plane at mach 3+ speeds......

    Some LM engineers have been quoted as saying it's actually dark blue, not black.
     
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  3. 598

    598 Well-Known Member Established Member

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    So the plane wouldn't ever have to be construed as racist? No flames, its just levity, and levity floats. Mull that line over, and sorry for the early hijack.
     
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  4. TK1299

    TK1299 Get on the banned wagon Premium Member Established Member

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    Because black is bad ass
     
  5. PhoenixM3

    PhoenixM3 Hello Kitty Slayer Established Member

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    I was gonna use "Black Planes Matter" but I got beat to the punch....
     
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  6. PhoenixM3

    PhoenixM3 Hello Kitty Slayer Established Member

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    Meh, Blue Bird doesn't conjure a menacing image.....
     
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  7. Smooth

    Smooth Well Seasoned Established Member

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    Cuz er'body knows:


    black-women-over-45-blackdontcrack-31007454.png
     
  8. 03Sssnake

    03Sssnake TK-421 Established Member Beer Money Bros.

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    Definitely, airframe cooling was the primary benefit...there is also some speculation the paint may have reduced the radar cross section as well.
     
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  9. GNBRETT

    GNBRETT Well-Known Member Established Member

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    Heat radiation to reduce thermal stress on the plane. Cooling benefits outweighed the disadvantage of increased weight from the paint therefore it was able to go faster.
     
  10. Gringo185

    Gringo185 2nd Civ Div Established Member

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    Black is better for single coat coverage?
    Fewer coats = less paint = less weight?
     
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  11. Double"O"

    Double"O" N2S come get some Established Member

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    Black is the ideal color for a proper recon acft because it doesn't reflect light and distort the image or mess with the lenses
     
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  12. 13COBRA

    13COBRA Resident Ford Dealer Premium Member Established Member

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    Wikipedia says that it's actually a dark blue color.

    Lockheed SR-71 Blackbird - Wikipedia
     
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  13. 03Sssnake

    03Sssnake TK-421 Established Member Beer Money Bros.

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  14. Silverstrike

    Silverstrike It's to big to move FAST! Established Member

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    Yes this was a little bonus when they did this on the black paint. I talked to quite a few ex Soviet SAM system operators everything from the SA-2 to the SA-10 (1971-89) and the Blackbird was one of the hardest targets to keep a constant lock on, as it would do a fade in and out, that was until you got to about 50 NM to it then if the radar was powerful enough it could maintain a lockon.

    The worst position to achieve a lock on was dead astern because of the zig zag trailing edge radar deflectors the plane had back there. The only systems the Soviets had that could give a SR-71 fits was the SA-10, SA-12, and the MiG 31 with AA-9 Amos long range active guided missiles.
     
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  15. 03Sssnake

    03Sssnake TK-421 Established Member Beer Money Bros.

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    The Mig 31 could only briefly maintain mach 3 on those intercepts...However they got their timing down and that along with the AA-9 scared us enough to start keeping our distance and eventually end the flights into Soviet airspace.
     
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  16. VegasMichael

    VegasMichael Well-Known Member Established Member

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  17. mysticsvt

    mysticsvt southernmustangandford Premium Member Established Member

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    Going with this guy...lol
    71.PNG
     
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  18. Sinister04L

    Sinister04L RIP Kane Established Member

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    Actually, lighter colors have better coverage than darker colors. Black would be the worst in that respect.
     
  19. Gringo185

    Gringo185 2nd Civ Div Established Member

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    Interesting. My limited experience with painting is that it’s easier to cover light colors with dark than dark with light.
     
  20. Sinister04L

    Sinister04L RIP Kane Established Member

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    It has to do with the base used. Light colors use a white or light base which has more titanium dioxide in it which makes it more opaque. Darker colors have a more clear base that has little to no titanium dioxide.
     
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