How do you guys calculate drift?

[blister]

This past 4th I had my first 1.3 mishap. I had a 6" willow shell launch, but never break. I feel fortunate that I didn't have a low break on the trip back down. That could have been bad. Once it hit the ground, it broke open and ignited a relatively small fire, which burned out before I could get to it with the fire extinguisher.

We had no wind at ground level, but I still had the racks angled just slightly into the direction of the prevailing winds. I don't know the exact angle, but I have levels built onto my racks so I could tell they would be angled into the wind if it did pick up. Well anyway, when the shell finally hit ground it was about 40 yards down-wind from the rack. I would have never thought it would drift back that far. Obviously, this shell went up high enough to find some wind.

So this brought up the question on how everyone accounts for drift?

[Playingwithfire85]

I am sure you could calculate drift by using similar equations for bullet drift but then again there is a speed issue. The speed of a bullet can be calculated for a specific round and can have very low ranges in speed differences. You would have to work with a median speed since a shell can vary extremely due to crude lift measurements and other factors of tube I.D. and so on. I would stick with recommended ranges for safety zones and not shoot in high winds but that's just me.

[blister]

Playingwithfire85, thanks for the reply.

I have the minimum safe distances covered. (So far I've only shot shows in my back yard). I was hoping to find something that would give me some indication of drift that I could use for future shows without having to think too much; like a table of shell sizes, wind speeds, and average drift. There always seems to be a hundred things going on, and it would be nice to not have to think too hard about this one.

Thanks.

[PGH_Pyro]

ive seen the charts that spell those out somewhere. just google for it . this question comes up on another pyro website , at times .