Thread: Which is the best wind meter for wind estimation

Originally Posted by Sidney

An exercise in simplicity I'm sure but would it be true to say.....

that one inch of drift approximating 1 MOA at 100m with continue to be 1 MOA = 10" approx drift at 1000m with no further wind

And no wind 0-900 but 1 inch of drift 900-1000 will result in 1 inch total dirt = 0.1 MOA....

Same amount of wind at different ranges...?

I assume this is why we average the wind for the total distance calc?

Wouldn't the projectile slow down more so over time it will blow further? So it wouldn't be moving at 1 inch every 100m it would be more the further it got out

Originally Posted by Toby

Wouldn't the projectile slow down more so over time it will blow further? So it wouldn't be moving at 1 inch every 100m it would be more the further it got out

Toby you should see Gillies explanation about that at the beginning of the thread. This understanding wind is a science and I reckon even if you got your masters degree in it you could still get it wrong.

fukit, here goes anyway

if you type in 10mph wind from 90 degrees in a ballistics calc like JBM, that means 10mph average, right ?

so 10mph blowing across the entire range the projectile is traveling ?

so if 10mph right wind gives 1 inch left deflection @ 100m (not actual, just for argument sake), some folks are saying that the deflection @ 1000m will be 10 times the 100m deflection i.e. 10 inches...

but if wind causes a deflection because of sideways pressure on the projectile (like the large ship example mentioned), would the effect not be compounded as opposed to linear ? test it for yourself, to me it looks more linear than compound, so maybe something else is going on ?

i think the danger is looking at a projectile as if it is a large polystyrene ball, and thinking that the force vectors involved with wind have a similar effect as those of forward velocity and rotational stabilization. now think of a modern hpbt design projectile, with very high forward velocity, high degree of stability due to rotation, and how those forces are working against any deflection due to wind...

something else to ponder... if you take a "yacht" shape, and put a dowel or mast thru it from top to bottom, exactly in the center. now imagine it pivots on that dowel. put the shape in a stream of flowing water. will the pointy bit (bow) turn upstream or downstream ?

The direction it's heading hasn't changed

There has only been a force applied to the side of it

The same force on that bullet will have greater effect on the bullet beyond 100 yards as the bullet slows
This is mostly due to the extra time the wind force has to act on the bullet as it slows

I still don't think its right, I may not be understanding it properly. But if its pretty much saying every 100m it moves an inch? I see that as wrong the bullet isn't moving as fast from 200m to 300m like it was from 0-100m

Toby, limit your shooting to 30 metres and it won't matter much. Ha ha ha ha

Here is one link http://www.6mmbr.com/winddrift.html

Originally Posted by ebf

fukit, here goes anyway

if you type in 10mph wind from 90 degrees in a ballistics calc like JBM, that means 10mph average, right ?

so 10mph blowing across the entire range the projectile is traveling ?

so if 10mph right wind gives 1 inch left deflection @ 100m (not actual, just for argument sake), some folks are saying that the deflection @ 1000m will be 10 times the 100m deflection i.e. 10 inches...

but if wind causes a deflection because of sideways pressure on the projectile (like the large ship example mentioned), would the effect not be compounded as opposed to linear ? test it for yourself, to me it looks more linear than compound, so maybe something else is going on ?

i think the danger is looking at a projectile as if it is a large polystyrene ball, and thinking that the force vectors involved with wind have a similar effect as those of forward velocity and rotational stabilization. now think of a modern hpbt design projectile, with very high forward velocity, high degree of stability due to rotation, and how those forces are working against any deflection due to wind...

something else to ponder... if you take a "yacht" shape, and put a dowel or mast thru it from top to bottom, exactly in the center. now imagine it pivots on that dowel. put the shape in a stream of flowing water. will the pointy bit (bow) turn upstream or downstream ?

As the bullet slows down while it is travelling the wind has the ability to effect for longer thus pushing it further off course the longer the distance

Ok DAF, so what do you see happening in the following examples:


a) 10mph right wind between 0 and 500. deflections at 100 and 500 ?

b) 10mph right wind between 0 and 100, no wind between 100 and 500. deflections at 100 and 500 ?

c) 10 mph right wind between 0 and 100, no wind between 100 and 400, 10 mph left wind between 400 and 500. deflections at 100 and 500 ?

Here is an interesting article about Naval Guns FIRE CONTROL FUNDAMENTALS - Part C

think of a pool table... if the white ball has force applied causing it to deviate from its intended path, what happens when that force stops..

whether the force is short (impact of another ball) or of longer duration (wind on a projectile) the result is the same..

Originally Posted by stug

Here is an interesting article about Naval Guns FIRE CONTROL FUNDAMENTALS - Part C

Bloody Hell.

No ... no Gillie, don't respond.... don't get dragged in... yes, there is some dodgy logic being applied but if you get dragged in you'll try to explain it... step away from the key board now... ok, now... just stop reading... now...


EBF got dragged in, even DAF replied... don't do it!!!!

Originally Posted by Gillie

No ... no Gillie, don't respond.... don't get dragged in... yes, there is some dodgy logic being applied but if you get dragged in you'll try to explain it... step away from the key board now... ok, now... just stop reading... now...


EBF got dragged in, even DAF replied... don't do it!!!!

Cuff yourdelf to the fridge and drink til the urge leaves you Gillie.

Dammit i am meant to be working....