Wind

[Turnup]

Because the pellet does not see air coming from two different directions it sees the combined flow from the wind and the forward speed. Assuming it is a stable pellet it will try to turn to face the combined air flow (that is the definition of a stable pellet) and therefore will have no flow on the side. The pellet is still being affected by the wind throughout the whole of its trajectory but it is the pellet drag which is making it drift to the side (hence the dependence on BC) not any force on the side of the pellet. The pellet drifts to the side because it is not actually pointing in the direction in which it is traveling relative to the ground so the drag force is pointing slightly to the side as well as to the back giving the pellet drift.
If your pellet does not turn to face the combined air flow you have more problems than wind to worry about.

Good explanation of some previous threads which have failed to convince me - this description I find persuasive.

Now to further my education, for a spinning pellet, as the pellet tries to turn into the combined air flow, there must be some precession effects?

Or are they so small as to be negligible?

Different for a bullet?

[ballisticboy]

Good explanation of some previous threads which have failed to convince me - this description I find persuasive.

Now to further my education, for a spinning pellet, as the pellet tries to turn into the combined air flow, there must be some precession effects?

Or are they so small as to be negligible?

Different for a bullet?

The pellet will precess, precession rates I estimate as about one cycle in 10 yards. This is a possible cause of pellet spiraling but spirals will be small. The effect of the precession yaw will be hidden by the down wind drift effect so will not really be noticed in practice.
The difference with a bullet is that its gyroscopic response will be different because it is aerodynamically unstable as opposed to a pellet which tends to be aerodynamically stable. The damping is also possibly better on many bullets giving a smaller effect for the precession.

[ballisticboy]

Really interesting.

I guess on a pellet though we're talking small amounts as we dont see them go sideways into paper... so would it be something akin to the angle between say the 600mph forward speed and the 10mph sidewind... ie a 600mph sidewind would see the pellet at a 45 degree angle?

Yes that is correct. With a side wind like that you would also get one hell of a vertical effect from the gyroscopic response to the pellet turning into the combined wind angle.

[Nevbag]

Yes that is correct. With a side wind like that you would also get one hell of a vertical effect from the gyroscopic response to the pellet turning into the combined wind angle.

Would the vertical effect occur regardless of wind direction?

[ballisticboy]

Would the vertical effect occur regardless of wind direction?

The direction of the vertical effect depends on the wind direction, the spin direction and the pellet aerodynamics. It can be up or down. The most pronounced effects were on the side guns on the world war two bombers which had an effective side wind of up to 300mph.

[Nevbag]

Many thanks for the answers on this thread, it has been educational to say the least.

Big apology to the OP for high-jacking but at least it is related.

Nev.

[RobF]

Yes that is correct. With a side wind like that you would also get one hell of a vertical effect from the gyroscopic response to the pellet turning into the combined wind angle.

Cool. Ta.

[Seamaster]

Many thanks for the answers on this thread, it has been educational to say the least.

Big apology to the OP for high-jacking but at least it is related.

Nev.

No need to apologise Nev, I've found it very interesting too.

Chris

[KeithW]

I did some not entirely objective and certainly not scientific testing on this and my conclusions were that .22 takes more wind than .177 if the wind is light and less wind than .177 if the wind is strong.

Hopefully that should satisfy both camps?

[Rich]

On the contrary, you've now made both camps absolutely livid that they've chosen the wrong calibre....

[RobF]

On the contrary, you've now made both camps absolutely livid that they've chosen the wrong calibre....

that makes .20 the worst out there then

[Rich]

Never had a 0.20 so I daren't offer an opinion.

[Valter]

If air is a fluid, which i think it is, and if it is flowing, then anything in that fluid will be carried by that fluid.
Just look at the ferry from Isla to Jura! The ferry headding has to be into the flow, to counteract that flow, and arrive at the pier!
Is it not the same for a pellet in air? The time interval is small, but the effect is the same! i think, or am i wrong?
My interest in this site is explaned in my first post, and involves the bore size of my .22 sharp ace.
Regards:
Valter.

[ballisticboy]

If air is a fluid, which i think it is, and if it is flowing, then anything in that fluid will be carried by that fluid.
Just look at the ferry from Isla to Jura! The ferry headding has to be into the flow, to counteract that flow, and arrive at the pier!
Is it not the same for a pellet in air? The time interval is small, but the effect is the same! i think, or am i wrong?
My interest in this site is explaned in my first post, and involves the bore size of my .22 sharp ace.
Regards:
Valter.

As with the pellet the ferry will head into the combined flow from the ferry's forward speed and the water flow rate. The ferry engine will provide sufficient thrust so that at the ferry cruise speed the engine thrust will equal the ferry drag giving a net zero drag force, (if the engine is not giving a net zero force the ferry will accelerate or slow down) just like the sustainer motor rocket mentioned before, and thus no drift with the water flow. In this way, assuming the captain gets it right, the ferry will end up where it wants to go and not down stream of the pier. If you were a static observer above the ferry you would see that, like a pellet, it was not pointing in the direction in which it is travelling.
Pellets because they have a net drag force will drift down wind, but the amount will depend on all the factors mentioned in previous posts, calibre being a relatively minor factor.

[Valter]

Thanks ballisticboy.
The ferry goes sideways like a crab!