For you ballisticians.

Obviously I did the right thing by taking a firm, rapidly alternating position on both sides of this debate. Thanks, Keith!

I hadn't considered the crosswind component of bullet velocity leaving the "band" of crosswind flow. I can see (qualitatively) how that matters.

Toby Bradshaw
baywingdb@comcast.net
 
Boyd Allen said:
2009-286-8-40-11-1-scan0001-1.jpg
Click to expand...


Al, in order to follow the flight path you have drawn in which the bullet continues traveling downwind upon entering the calm condition; in order to do that the bullet would have to be skidding sideways in the airmass and I assure you it cannot and will not do that when moving through the airmass at 2000 fps. :)

Gene Beggs
 
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Bye for now,,

Guys it sure has been fun but I must excuse myself for about three days. I have guests arriving this morning for some work in the tunnel.

Keep up the lively discussion and let's explore this until we all understand completely how bullets really behave in the wind.

Fascinating; isn't it? :D

Later

Gene Beggs
 
Gene Beggs said:
Al, in order to follow the flight path you have drawn in which the bullet continues traveling downwind upon entering the calm condition; in order to do that the bullet would have to be skidding sideways in the airmass and I assure you it cannot and will not do that when moving through the airmass at 2000 fps. :)

Gene Beggs
Click to expand...

pilots :D

You're right......

if this was an airplane!!!! :):)

which it ain't

al




You know what Gene? An acquaintance of mine just handed in is license because he "forgot how to fly"...... really, he got up and when he came to set 'er down even the tower couldn't get his head screwed back on, he went tail-to nose-to tail-to nose and tried to bore a hole in the ground... 'course his wood prop wasn't up to the task..... I never rode with him and don't know that I'd want to.....

Guys like YOU on the other hand have rules of flight so deeply ingrained into your collective psyches (ooops, guess that's heli drivers.. ;)) that you flat out live by them, can't even consider alternatives.... :) .... airchines just DO IT THIS WAY!!!

I would fly with you! :):):)

comfortably..

But bullets don't fly.....

The reason that bullet in my picture doesn't skid across the sky until it pancakes is because it's SPIN stabilized, it just hunts with its nose until it finds the new wind and blithely coasts on.

A bullet doesn't fly on surfaces. The bullet just lobs on and the surfaces stay out of the way, presenting as little of themselves as possible if they want to remain in the air.

alagain
 
Gene Beggs said:
Al, in order to follow the flight path you have drawn in which the bullet continues traveling downwind upon entering the calm condition; in order to do that the bullet would have to be skidding sideways in the airmass and I assure you it cannot and will not do that when moving through the airmass at 2000 fps. :)

Gene Beggs
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Gene
I had originally thought that this was your drawing. My bad.
Al you did a fairly creditable job of drawing the true flight path - being curved in the "howling crosswind" and straight in the calm.

Problem is....you put Al's name upon that path. (When I thought Gene had drawn it)

An object at rest or in motion will remain at rest, or in motion along a straight path, until acted upon by an outside force. What outside force would be required to return the bullet to the path you project - one parallel to the original line of aim? Only an oposite acting "howling crosswind"...I didn't see one of those in the Gene's path drawing.
 
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Vibe said:
Gene
You did a fairly creditable job of drawing the true flight path - being curved in the "howling crosswind" and straight in the calm.

Problem is....you put Al's name upon that path.

An object at rest or in motion will remain at rest, or in motion along a straight path, until acted upon by an outside force. What outside force would be required to return the bullet to the path you project - one parallel to the original line of aim? Only an oposite acting "howling crosswind"...I didn't see one of those in your drawing.
Click to expand...

you engineers....... you just operate on another plane don't you :)

Is it simple dislocation? humor? disassociation??

the result of never being questioned?

we mortals sometimes wonder

this one anyways

daily

:confused:

al
 
Vibe said:
Now THAT's funny. :D
Even more so coming from you. One who continues to question. :rolleyes:
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OK,

so vibe, who are you 'with' now....... Gene's camp or alinwa's?

They're (for now) on opposite sides of da' ribber...... my camp's getting larger, we're ready to elect a Mayor and start a small school......

BTW, I agree with your assessment of "Gene's illustration".... or, you must agree with mine? :)eek:) since I already covered this 'wayyyy back on another page? Long before the picture.....I mean, do you READ this stuff?

Nothing's changed about how a bullet flies, since The Mother Of All Winddrift Threads, nothing's changed..... shoot, since Didion b'zackwards figgered it, nothing's changed......... except the perspective of the various folks in this thread.

Toby is (I think) really starting to see it (ooops! it ain't a plane!) .... and some of the guys like Tony and Keith have perty much had it all along.....

And we've had a lesson on trusting "experts" VS really understanding the physics. The physics, not the math.

al

And BTW, you didn't answer my question from the post you commented on.....

lemme' guess... humor? You were being funny? It's been years since I had to have a joke explained to me, but ...... I need help here.... I'm not trying to be rude, I'm trying to understand that you're "not" being rude/obtuse/abstruse???

And on the bullet tipover thing, I haven't let it go..... I'm not in agreement w/you and N-R but I haven't closed my mind to the possibility of "overstabilization".... if I can find a credible mechanism I'll rerun the numbers.

This IS true in my current model, a faster spinning ("more stable") projectile exhibits an angle of repose which is further from centerline of trajectory.

But nothing to keep it from nosing over.

But then I've yet to replicate the rips you refer to. Empirical data does carry a lot of weight! :) I'll try some more.
 
To vibe..... an unrelated question.

Vibe, if an overstabilized bullet doesn't tip over to follow it's flight path, does it follow that an overstabilized bullet shows increased "wind drift?"

In my model a faster spinning bullet shows increased VERTICAL drag displacement but no extra wind drift....

Your turn, yes or no?

al
 
alinwa said:
To vibe..... an unrelated question.

Vibe, if an overstabilized bullet doesn't tip over to follow it's flight path, does it follow that an overstabilized bullet shows increased "wind drift?"

In my model a faster spinning bullet shows increased VERTICAL drag displacement but no extra wind drift....

Your turn, yes or no?

al
Click to expand...
Any increase in drag - from any vector - means that the relative airflow will have more effect upon the path of the bullet - so yes the "overstabilized" bullet will most definately exhibit more drift - as well as a marked drop in BC once it is no longer able to remain nose-in to the airflow.
 
Vibe said:
Any increase in drag - from any vector - means that the relative airflow will have more effect upon the path of the bullet - so yes the "overstabilized" bullet will most definately exhibit more drift - as well as a marked drop in BC once it is no longer able to remain nose-in to the airflow.
Click to expand...


Kapische

And I thank you for understanding and clearly stating your position.

al
 
My appologies Al. I mistakenly thought that the drawing was BY Boyd and Gene. Which I thought was a bit humorous, if strange. I stand corrected and have edited my response statement to it.

It would have been even more accurate had the continuing line been tangent to the curved path in the crosswind...but that's a VERY minor detail.
Basicly whoever drew it was real close to accurate and correct. And as Gene pointed out it WILL slew sideways relative to the rapid change in airflow conditions...at least until it's new equilibrium angle can be found. Which if I understand YOUR drawing...is exactly what you tried to illustrate.
 
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Vibe said:
And as Gene pointed out it WILL slew sideways relative to the rapid change in airflow conditions...at least until it's new equilibrium angle can be found.
Click to expand...

And THIS my friend is specifically why it can't be tangent..... look closely at the drawing to see fishtailing on Al's path.... :)

If my 10min knee-jerk drawing needs editing I'll freakin' FIX IT!!

:D:D

al
 
Al,

I think your drawing posted by Boyd depicts exactly what happens under the described conditions. I would consider the bullet path vector at 600 yds in your sketch to be the "new" angle of departure and the bullet turns point on in that differentiated air mass to travel in a straight line but at a small angle to the original path (0 to 500) and not parallel as Gene has objected. I find myself surprised and uncomfortable to be at odds with a perspective of Gene's. I hope Gene revisits this soon. Maybe Bryan will tell us what is actually happening in this example. Keith, Toby, what say you?

It is exactly for the bullet behavior described in your sketch that I believe that what is happening to the air at the shooter is of more consequence to drift than what is happening down-range where we usually watch for mirage. That and the fact that initial yaw degrades BC until it damps out.

Last week between Match 8 and Match 9 at the F-Class Nationals, Don Nagle was describing his frustration with the spread between what he was seeing in the often contradictory flags and the results he was getting on target. I suggested paying more attention to what was happening up close. In Match 9 Don dropped two points, an improvement over 7and 8. He told me he watched to surface of the Butner swimmin' hole in front of the let side of the 1K firing line for info and believed it made a difference, joking that I should have told him earlier. I don't think that Don needs any advice from me on reading the wind but his performance was the only good thing that happen to me during Match nine.

Greg
 
alinwa said:
And THIS my friend is specifically why it can't be tangent..... look closely at the drawing to see fishtailing on Al's path.... :)

If my 10min knee-jerk drawing needs editing I'll freakin' FIX IT!!

:D:D

al
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LOL. Your drawing is fine. OK. The bullet MIGHT "fly" to the right a bit during it's "slew" into calm air since the reactive force caused by the unballanced attitude WILL have some effect upon the bullets path. It too will be a curved path, but on the scale of your drawing it will be of such short duration that it might appear to be a sharp turn.
 
I stayed out of this discussion as long as I did becasue the original question was flawed.
I keep reading that a bullet with the higher BC will experience less wind drift regardless of bullet weight,
Click to expand...
Has anyone got any information at all on two bullets with approxamately the same BC, but with much different bullet weights? Or even two bullets of equal weights but vastly differeing BCs (the latter case is more likely, blunter profiles or even different calibers - a very light .30 vs a very heavy .22 or 6mm).

Since the value of BC is itself a measure of how that bullet reacts to the air flow - it more or less includes the way a bullet of that mass will react.
 
See this is a 'wayy better thread than TMOAWDT (The Mother...) because this time we got's TONY, wit' PIXSTURES!!!

:D:D

(I still can't get over that Tony.... you ROCK man!)

LOL

al
 
Vibe said:
I stayed out of this discussion as long as I did becasue the original question was flawed.

Has anyone got any information at all on two bullets with approxamately the same BC, but with much different bullet weights? Or even two bullets of equal weights but vastly differeing BCs (the latter case is more likely, blunter profiles or even different calibers - a very light .30 vs a very heavy .22 or 6mm).

Since the value of BC is itself a measure of how that bullet reacts to the air flow - it more or less includes the way a bullet of that mass will react.
Click to expand...


Yes,

There are hundreds of examples. What do you mean "does anyone have information"????

I plug the numbers into my computer and shoot this stuff over the chrono allatime...... and the real world difference between cheesy programs like RCBS Load and Sierra Infinity and Pejsa VS real-world is down in the freakin' DUST man....

BC is BC..... independent of, actually derived from, all of the above.

As are all "coefficients"...... aren't they?

al
 
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