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Placement and Calibration - T1 Older Model

Placement If you use the T1 as your primary windflag, you should use this formula: T*0.33, where T is target distance. The resulting distance is the placement from your position to where you should place the T1. The reason for the 1/3 rule is the ballistics changes caused by wind between the muzzle and this traveled distance, have about 65-70% of the total change of the entire distance. Put in perspective, if there was a 10mph cross wind from the right in the first 1/3, and a 10mph cross wind from the left the rest of the way, the poi would still not quite catch up to zero. Below is an example using a target at 50m, resulting placement distance using the simple...

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CFD analytics on a local range

Background As anyone would have experienced ever shooting at Rio Salado, the wind conditions are tricky, and ever present. Personally I have never seen a calm day shooting at that range. Given the various berms, structures and other terrain features and obstacles, I was interested in looking at the flow across the range. So I decided to run some Computational Fluid Dynamics across it. I've done the left side and the right side separately, since the structures are different. I have also ran the center where there is a blockage that have some effect on it on the positions directly next to it.The weather specific condition for this CFD run was as follows, and what I find typical at Rio...

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Spin Drift / Magnus effect

Spin Drift/Magnus effect - What is it? A variable that isn't well understood by most, but here is a youtube video showing the effect on a basketball falling with a backspin. As you can see the effect is not only real, but have quite a profound effect on the trajectory. The reason it does this, is due to pressure differential created by the spin itself. On one side the surface moves with the airflow, and on the opposite side it moves against the airflow direction. This creates a difference in pressure, and as rudimentary high school science knowledge have taught us, things wants to move from high pressure towards low pressure. There is also airflow separation on the side that...

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Wind Conditions 001 - Head Wind

    In an effort to understand wind, I'll post some details about common conditions that might not seem obvious to everyone. This post will discuss head wind, but it applies to tail wind to some degree as well. If you look at the illustration You got your position, and the target at the other end of the range. And behind that your typical backstop in form of a berm. When shooting at targets in head wind, you don't really have to account for holdover in terms of drop caused by slowing of the projectile. But this only holds true if the berm/obstacle is relatively far behind the target. If it is close to the target, I would say within 4X...

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