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Old 3rd October 2013, 08:04 PM
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Brian.Samson Brian.Samson is offline
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Join Date: Jun 2009
Member of: Pontefract, Doncaster Airgun Range
Location: Doncaster
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Originally Posted by rich View Post
Now, our little airgun pellet is like the stick. Ultimately, if gravity didn't pull it to the ground first, it would travel along in the wind, at the same speed as the air molecules. Much like a dandelion seed. But initially, at the instant the pellet exits the barrel, it has zero speed in the direction of the wind. Take a broadside wind for example as it's easier to imagine. So, if the pellet accelerates sideways from a zero vector to equilibrium with the wind, there has to be a force acting upon it, same as the stick in the water.

Yup, that's what confuses me too Rich - well spotted

Now for an aircraft this acceleration to the speed of the wind isn't significant and it happens almost instantly at the point of take off (or rotation), but an airgun slug is only travelling for a very short period of time so this acceleration must make a difference surely? I'd have thought anyway.

I did say I'm not a ballistics expert, I was trying to explain why side profile isn't taken account of in the wind calculations (directly) in the same way it was explained to me.

I have no idea whether the wind drift calculation is correct, but I know it's been used for a long long time with accurate results by people with access to a lot more testing resources than any of us have got, so who am I to disagree with them.
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