Author Topic: Gyroscopic effect (spin/magnus) on pellets in the wind. - Need your help  (Read 2333 times)

Windmeister

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So how do I phrase this without being too nerdy...

Ok, I am going to assume that you are not familiar with spin/magnus/gyroscopic effect on the trajectory of the pellet in the wind. That is a deflection contrary to the wind direction in windy conditions caused by uneven pressure zones above and below the pellet. These are created as a result of the spinning pellet, creating low/high pressure on the perpendicular sides of the pellet in relation to the wind direction. 
Ok, that's the nedry bit, in normal terms, it means that in wind from say the left, you get a drift to the right, but you also get a deflection up or down caused by the gyroscopic effect depending on which way your pellet is rotating, clockwise or counterclockwise.

The new Chairgun have a new applet that let's you calculate this based upon field data.
So here we are at the help bit of the thread.

What we need from you is, if you want to, it's absolutely voluntary, to document these data points:
Velocity, pellet used, target distance, wind drift, vertical drift(not ballistic drop) so the target distance must be your zero distance, wind speed and direction.
Then if you know your rifling pitch (inch pr.) it will be useful too.

With enough data point we can create a pretty accurate prediction model to use.



oldpro

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Man This is where the doppler radar would shine.
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Monkeydad1969

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Man This is where the doppler radar would shine.

LMBO!
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Joe the P-Dawg Slayer!!!!!

Dairyboy

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This makes a lot of sense to me now. Yesterday wind was coming from behind and the left and I had some rather open strings from my .22 and .177. Both typically are very accurate one hole groups at 25 yds but yesterday they were both strung out from right on the money to low and right which wasn't making sense. I expected it to shoot to the right but not lower. But knowing that wind will affect spin on the pellet causing it to deflect makes sense and why it dropped my poi as well as shifted it horizontally.
  • Outlook, WA
John 3:16

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ztirffritz

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The Magnus effect in action:
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strever

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DB
what gun & what barrel where you shooting ?
your description is the opposite of what my guns do

Dick


This makes a lot of sense to me now. Yesterday wind was coming from behind and the left and I had some rather open strings from my .22 and .177. Both typically are very accurate one hole groups at 25 yds but yesterday they were both strung out from right on the money to low and right which wasn't making sense. I expected it to shoot to the right but not lower. But knowing that wind will affect spin on the pellet causing it to deflect makes sense and why it dropped my poi as well as shifted it horizontally.
Dick

airgun collection too big to list here

Dairyboy

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DB
what gun & what barrel where you shooting ?
your description is the opposite of what my guns do

Dick


This makes a lot of sense to me now. Yesterday wind was coming from behind and the left and I had some rather open strings from my .22 and .177. Both typically are very accurate one hole groups at 25 yds but yesterday they were both strung out from right on the money to low and right which wasn't making sense. I expected it to shoot to the right but not lower. But knowing that wind will affect spin on the pellet causing it to deflect makes sense and why it dropped my poi as well as shifted it horizontally.

Ones a .22 mrod with hammer forged barrel and the .177 is a mac1 disco.
  • Outlook, WA
John 3:16

.177 Nova Freedom
.177 TJ barreled Huma regulated LW airtube
.22/.30 WARP COBRA

Windmeister

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What twist direction and what ammo where you shooting?

Dairyboy

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What twist direction and what ammo where you shooting?
I'm pretty sure hammer forged barrel is a clockwise and assuming disco is also but not 100%. 18.13 JSB and 10.34 AAs.
  • Outlook, WA
John 3:16

.177 Nova Freedom
.177 TJ barreled Huma regulated LW airtube
.22/.30 WARP COBRA