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Math Help - Occasional Puzzle Anyone?

  1. #1
    Grand Panjandrum
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    Occasional Puzzle Anyone?

    I first saw this question on the usenet group sci.math many years ago,
    but see below for what I believe is its true origin.

    This is allegedly a true story.

    ================================================== ======

    Early in the Cold War the Soviet Union sought to defend its bombers by fitting
    rearward* firing missiles**

    Every time this was tried the missile would make an immediate U-turn and hit
    the aircraft that fired it. Why was this?

    *At that time the best position from which to attack a bomber was from
    behind, as less/no deflection or lead was needed on unguided weapons, and
    early Infra-Red homing missiles needed to see the hot exhaust to lock-on.
    Also this is the easiest intercept geometry when using Ground Controlled
    Intercept.

    **One source quotes missile in the singular, I would have thought it more
    likely that they tried multiple fin or spin stabilised unguided rockets, which
    were a common air-to-air weapon at the time.

    (Paraphrased form "The Chicken From Minsk" by Chernyak and Rose, with
    comments added by CaptainBlack).

    ================================================== ======

    RonL
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  2. #2
    Global Moderator

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    Because the Soviets do everything backwards?

    Because the missles were manufacted by Americans?
    Last edited by ThePerfectHacker; August 6th 2006 at 08:31 AM.
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  3. #3
    MHF Contributor Quick's Avatar
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    Because Stalin was afraid the bomber pilots were getting to be too "suspicious"
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  4. #4
    dan
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    Talking

    my brother thinks that they were heat seeking ...that would be cool, hahaha
    dan
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  5. #5
    Grand Panjandrum
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    Quote Originally Posted by dan
    my brother thinks that they were heat seeking ...that would be cool, hahaha
    dan
    [LECTURE=early heatseeking missiles]
    The seeker has a limited field of view, and the firing aircraft would never
    be in that field and so was invisible to the seeker.
    [/LECTURE]

    RonL
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  6. #6
    Grand Panjandrum
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    Quote Originally Posted by Quick
    Because Stalin was afraid the bomber pilots were getting to be too "suspicious"
    I suspect when the phenonenem was explained that someone visited the
    Soviet far east in consequence

    RonL
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  7. #7
    Grand Panjandrum
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    Quote Originally Posted by ThePerfectHacker
    Because the Soviets do everything backwards?

    Because the missles were manufacted by Americans?
    None of these

    RonL
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  8. #8
    MHF Contributor Quick's Avatar
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    just a guess

    maybe it was because one of the latches holding the missile to the plan would releace a tad bit late, forcing the rocket to turn in such a way that the propulsion in back sould send it in a circle and the rocket would then hit the bomber...
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  9. #9
    Grand Panjandrum
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    Quote Originally Posted by CaptainBlack

    Early in the Cold War the Soviet Union sought to defend its bombers by fitting
    rearward* firing missiles**

    Every time this was tried the missile would make an immediate U-turn and hit
    the aircraft that fired it. Why was this?
    Hint:

    Why does an arrow point in the direction of its flight rather than tumble,
    or just retain the attitude it has when released?

    RonL
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  10. #10
    Grand Panjandrum
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    Quote Originally Posted by CaptainBlack
    Hint:

    Why does an arrow point in the direction of its flight rather than tumble,
    or just retain the attitude it has when released?

    RonL
    Hint2 (Hold down left rodent button and drag over space between lines

    ================================================== =


    In order to keep a arrow pointing in the direction it is going it is
    fitted with fletchings (flights) which have the effect of moving
    the centre of pressure when in flight backwards along its length
    so it lies behind the centre of mass.

    The result of this is that if there is a discrepancy between the
    arrows axis and its direction of flight (in fact the direction of the
    apparent wind/air flow) the aerodynamic force acts behind the
    centre of mass giving a couple acting on the arrow in such
    a direction that it tends to turn it to reduce the discrepancy.

    We call this aerodynamic stability (at least it is one aspect thereof).


    ================================================== =

    RonL
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  11. #11
    Grand Panjandrum
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    Answer (select blank area to see the answer)

    The rockets were dynamically stable as described in the hints. That means
    that the rocket will flip to point into the apparent wind.

    When the rocket is fired it is moving at the same velocity as the launching
    aircraft, so the apparent wind is coming from behind the rocket, so it flips
    around to point back at the aircraft.


    RonL
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