how does wind direction affect flight ?

Discussion in 'Long Range Hunting & Shooting' started by splattermatic, Apr 14, 2010.

  1. splattermatic

    splattermatic Well-Known Member

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    we all know that a wind from left or right causes the bullets to drift left or right.
    but,
    how does a tail wind or head wind affect trajectory ?

    i noticed today, that i was on with no wind, but a straight tail wind of about 10 mph got up, and when i shot again at 550 yards, i was hitting a bit low.

    does a tail wind cause the bullets to drop quicker, and a head wind cause them to rise ?
     
  2. Long Time Long Ranger

    Long Time Long Ranger Well-Known Member

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    Strong head winds or tail winds will cause you to shoot slightly high or low as the bullet travels through air pockets and turbulence. Tail wind will increase velocity slightly more than a headwind will slow it down because of the large base of the bullet vs the sharp point in front resists the air better. The base has more surface to push on. Tailwind you should shoot slightly higher with more velocity, headwind slightly lower with less velocity. Most rifles will shoot 2000-2500 mile per hour so figure a 10 mph wind and depending on the exact shape of the bullet it will not be 10 mph faster or slower and you see how slight it would be. In a perfect vaccum the vector could be calculated quite easily but it would take a lot of testing to figure the effect of each bullet in the wind to get the coefficient to put into the equation to make it accurate..
     
  3. splattermatic

    splattermatic Well-Known Member

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    makes sense, guess i need to reshoot and test again.

    thanks
     
  4. Chas1

    Chas1 Well-Known Member

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    LTLR, makes sense. Not that a bullet and a plane are identical but just like in a plane with a good tailwind it will cut flight time say LAX to Atlanta by as much as a 1/2 hour so says the pilot. I'm sure a strong headwind would probably slow a flight down although the pilots maybe throttle up to keep from arriving late.
     
  5. Buffalobob

    Buffalobob Well-Known Member

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  6. Long Time Long Ranger

    Long Time Long Ranger Well-Known Member

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    Buffalobob, So by that the twist affect would outweigh the slight gain or loss in velocity. The velocity effect would be slight in a small wind so the twist effect must be more according to that. I can tell you from shooting out west directly into one of our 20-30 mph headwinds you better aim just a tad high. How much is an experienced guess. With a strong crosswind throw the twist out the door because it will take the bullet with the wind. I bet there is a relation to how much wind it takes to overcome the twist effect.

    About the airplane, I have been on many flights to Alaska and east to west across the country and late many times because of headwinds. Happens a lot.
     
  7. Buffalobob

    Buffalobob Well-Known Member

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    What Milanuk said

    Of course Milanuk shoots a Savage so he obviously don't know much and I don't care how many trophies he won last week at the F-class shootout. :D

    The fact that the bullet is spinning affects how a lateral force will move it. Whether the bullet spin is right hand or left hand will change it form high to low or vice versa with a lateral wind
     
    Last edited: Apr 14, 2010
  8. Long Time Long Ranger

    Long Time Long Ranger Well-Known Member

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    Buffalobob, I am no guru on this by any means. I am just using my physics and applied math degrees from your alma mater to try and figure it out. I also have shot a lot in the wind. I know headwind and tailwind is very slight and uphill and downhill have a much greater influence. Twist also is a slight effect. I can visualize a baseball curve ball at 70 mph how much it breaks and then think about the rate of spin on a bullet at 2300 mph. Amazing it shoots as straight as it does in the wind.
     
  9. elkaholic

    elkaholic Well-Known Member

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    Regarding up and down hill, that is where a head or tail wind really DOES have an affect. Depending on the slope angle and wind speed, the affect can be dramatic. Same principals apply to slope angle as to crosswind angle. i.e. 10 mph headwind down a 45 degree slope would cause same drop as 10 quartering crosswind would cause drift.....Rich