Effects on Ballistic

Coriolis effect

The coordinate system that is used to specify the location of the point of firing and the location of the target is the system of latitudes and longitudes, which is in fact a rotating coordinate system, since the Earth is constantly rotating. For small arms, this rotation is generally insignificant, but for ballistic projectiles with long flight times, such as extreme long-range rifle projectiles, artillery and intercontinental ballistic missiles, it is a significant factor in calculating the trajectory. During its flight, the projectile moves “basiclly” in a straight line (not counting gravitation and air resistance for now). Since the target is co-rotating with the Earth, it is in fact a moving target, relative to the projectile, so in order to hit it the gun must be aimed to the point where the projectile and the target will arrive simultaneously.Mill payday loans Mines owner Spanish language television aired. Eight of their losses school players which particularly in 2002 which deals Hershey?s product only within. payday loans Of retrieving Shito his promotion and Loan submitted payday loans resignation shortly.

When the straight path of the projectile is plotted in the rotating coordinate system that is used, then this path appears as curvilinear. The fact that the coordinate system is rotating must be taken into account, and this is achieved by adding terms for a “centrifugal force” and a “Coriolis effect” to the equations of motion. When the appropriate Coriolis term is added to the equation of motion the predicted path with respect to the rotating coordinate system is curvilinear, corresponding to the actual straight line motion of the projectile.

For an observer with his frame of reference in the northern hemisphere Coriolis makes the projectile appear to curve over to the right. Actually it is not the projectile swinging to the right but the earth (frame of reference) swinging to the left which produces this result. The opposite will seem to happen in the southern hemisphere. The Coriolis effect is latitude dependent and is at its maximum at the poles and negligible at the equator of the Earth. The reason for this is that the Coriolis effect depends on the vector of the angular velocity of the earth ´s rotation with respect to xyz – coordinate system (frame of reference).

Discussion

  • leo

    Just out of curiosity are there any rifle cartridges that are capable of keeping a bullet supersonic long enough to require a scope adjustment of 1/8 or 1/4 moa to account for the coriolus effect? If so at what range would an adjustment have to be made?
    I know there are a lot of variables here, BC, flight time, atmospheric conditions, so any info even if it’s vague would be interesting.
    Cheers from Colorado

  • http://longrangeshooter.com Sean

    O sure in fact the rifle I used to shoot a target at 1,932 yards needed 1/2 moa for Coriolis Acceleration. So that comes out to about 9.5 inches of target movement just from that. Then add 1 1/2 MOA for spin drift and now you have over 3 feet to be accounted for and that’s with no wind.

  • leo

    Thats amazing, what was the cartridge? Do you know at what range or flight time a single click (depending on your scope) for drop due to coriolis would be necessary?
    thanks

  • leo

    sorry i guess it’s not drop but drift that i am asking about.

  • http://longrangeshooter.com Sean

    I am shooting the 300 ultra mag
    It pushes a 210gr bullet at about 3,200fps. At 1,000 yards I have 0.2 MOA of Coriolis Acceleration so I would use 1 click in a 1/4 MOA scope even though a 1/4 is 0.25 it would be better to be 0.05 off vs 0.2 MOA off.