Re: Most Important wind
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Kinda unorthodox, but maybe once one gets past the orthodoxy, it might even seem kinda intuitive.</div></div>
Greg,
That reminds me of an Arthur Schopenhauer quote:
"All truth passes thru three stages. First is is ridiculed, second it is violently opposed, finally it is accepted as being self-evident".
This thread reminded me of a simulation I set up a while ago to study the effects of wind gradient. It's a 6-DOF representation of the .30 cal 175 grain SMK at a MV of 2800 fps zeroed for 1000 yards in standard conditions. The following plots show the bullet's trajectory from the shooters point of view as it arcs up to just over 10 feet, then down to the target.
There are 3 traces on each plot for 3 wind conditions.
1. Blue is zero wind. The model predicts about 9.8" of spin drift in this case.
2. The red trace is the bullet deflection in a constant 10 mph crosswind.
3. The black trace shows how the bullet is deflected for a wind that starts at zero in the grass, and grows in speed by 1 mph for every foot above the ground. So at the bullets apogee, the wind is just over 10 mph.
This first plot shows the uncorrected trajectories for all 3 cases:
The zero wind trajectory has 9.8" of deflection (spin drift)
The constant wind trajectory has 108.5" of deflection total (wind + SD)
The variable wind trajectory has 82.3" of deflection total (wind + SD)
This second plot shows the corrected trajectories for the 3 cases. You can see the trajectory 'lean' into the wind as described in previous posts.
This isn't presented to argue or conflict any of the observations made above, just some graphical insight into the effects of a wind gradient.
I find it interesting that the wind gradient case results in so much wind deflection (~80% of the constant wind) even though the bullet is exposed to less than 10 mph crosswind for much of it's trajectory.