Does a RB travel with constant rotation, or accelerate?

[tenngun]

11:55 local time, is it to early to have a beer to counteract the headache this is causing me?

 

[rdlowe]

It’s 5 o’clock somewhere.

 

[tenngun]

So, it’s all thought experiments until we get hard evidence. We could paint a line on a ball and shoot it. We could have a high speed camera that would film the ball at one hundred and two hundred yards. If we could catch the last four feet we could count.
Hold it though. Should you want to know the temperature of a glass of water you can stick a thermometer in to the water. However unless the probe and the water were exactly the same temp the probe would change the temperature of the water. So we learn the temp of the water after we stick the probe in.
Would the weight of the stripe of paint on our filmed ball upset the results?

 

[tenngun]

I think that the stabilization of the ball imparted by the spin is the greatest force that's acting on the ball in relation to it's arc, then adding the friction being slightly greater on the bottom of the ball (forward+downward) would tend to keep the axis of the spin in line with the direction of it's flight while at the same time adding to the slowing of the spin on it's downward trajectory.

Once again, no warranty implied or given...

That’s what I’m thinking. It would maintain its initial 1/48, or even slow a bit from there.

 

[Carbon 6]

I think that the stabilization of the ball imparted by the spin is the greatest force that's acting on the ball in relation to it's arc, then adding the friction being slightly greater on the bottom of the ball (forward+downward) would tend to keep the axis of the spin in line with the direction of it's flight while at the same time adding to the slowing of the spin on it's downward trajectory.

Once again, no warranty implied or given...

Does deceleration of spin decrease as the velocity decreases ?
I think it does because drag force decreases with velocity.

 

[Carbon 6]

11:55 local time, is it to early to have a beer to counteract the headache this is causing me?

Boy are we in sinc, I just grabbed a can of thinking fluid.
Wait, you said "too early" it's never too early.

 

[Carbon 6]

We could paint a line on a ball and shoot it. We could have a high speed camera that would film the ball at one hundred and two hundred yards. If we could catch the last four feet we could count.

I think the experiment has been done, using Doppler radar.

 

[tenngun]

I think the experiment has been done, using Doppler radar.

Wow
Need to look this up. One real life experiment is better then a million thought experiments

 

[Carbon 6]

Wow
Need to look this up. One real life experiment is better then a million thought experiments

Don't quote me, working from memory.

 

[rdlowe]

Wow
Need to look this up. One real life experiment is better then a million thought experiments

Do a search for viscous torque.

 

[tenngun]

I understand.

 

[bisleyjohn]

Boy are we in sinc, I just grabbed a can of thinking fluid.
Wait, you said "too early" it's never too early. View attachment 39477

Me too, cheers!

 

[Bob McBride]

Does deceleration of spin decrease as the velocity decreases ?
I think it does because drag force decreases with velocity.

I’m pretty sure it does but I would like to know what sort of 1/48 spin is left on a RB at it’s max possible range of say 1500-2000 yards. That would tell us a lot.

 

[tenngun]

Do a search for viscous torque.

Can’t call it a fun read, but informative.

 

[Zonie]

Just to stir the pot a little, here is the original question that was asked in the first post:

"Does the RB continue rotation of 1 turn every 4', or does it accelerate to a faster rotation? "

Notice, the question is, "does the RB continue rotation of 1 turn every 4'. That makes distance traveled enter the picture, not rotation per minute or second .

If the ball was spinning once every 4 feet at a given velocity and we ignore the slight reduction in RPM that might happen as the ball fly's downrange when the velocity slows down it will take longer to cover that same 4 foot distance.
Since the RPM of the ball hasn't changed and it takes longer to cover that distance the ball will spin more times per foot traveled than it did when it left the muzzle.
Just picking numbers out of the air for an example, if the ball rotated once every 4 feet at 1500 feet per second and the velocity slowed down to half of that speed (750 fps) it would spin twice in the four feet distance traveled. If the velocity slowed down to 1/4 of the original 1500 fps velocity (375 fps) it would spin four times while it was covering that 4 foot distance so, if the number of revolutions the ball makes every 4 feet is the standard we are using to judge the speed of rotation then yes, the speed of the balls rotation is increasing as it fly's downrange.

 

[Bob McBride]

That’s the question. How ‘slight’ is the reduction in RPMs? If it’s very slight, say, by 100y it’s still doing 1/47, that’s one thing, but if it’s doing 1/47 10’ out of the muzzle and 1/40 at 50 yards, 1/35 and 100 y, etc. that’s a whole other calculation....I think the only place it’s spinning an actual 1/48 is in the bore. It doesn’t take 1/48 to stabilize a RB, it takes that to get it to whatever the max effective range is, still stabilized. It seems to me...

 

[Carbon 6]

Just to stir the pot a little, here is the original question that was asked in the first post:

"Does the RB continue rotation of 1 turn every 4', or does it accelerate to a faster rotation? "

Notice, the question is, "does the RB continue rotation of 1 turn every 4'. That makes distance traveled enter the picture, not rotation per minute or second .

If the ball was spinning once every 4 feet at a given velocity and we ignore the slight reduction in RPM that might happen as the ball fly's downrange when the velocity slows down it will take longer to cover that same 4 foot distance.
Since the RPM of the ball hasn't changed and it takes longer to cover that distance the ball will spin more times per foot traveled than it did when it left the muzzle.
Just picking numbers out of the air for an example, if the ball rotated once every 4 feet at 1500 feet per second and the velocity slowed down to half of that speed (750 fps) it would spin twice in the four feet distance traveled. If the velocity slowed down to 1/4 of the original 1500 fps velocity (375 fps) it would spin four times while it was covering that 4 foot distance so, if the number of revolutions the ball makes every 4 feet is the standard we are using to judge the speed of rotation then yes, the speed of the balls rotation is increasing as it fly's downrange.

Bad Zonie.
Trying to confuse me with linear math.

 

[rdlowe]

Can’t call it a fun read, but informative.

Heh. In this day and age one would expect we could easily model an object flying thru the air, especially a simple thing like a lead ball. Some of the questions people are asking in this thread are tickling the periphery of human knowledge, tho. The closer we want to get to a precise answer, the more difficult the question becomes. Some of the aerodynamics in question aren't fully understood, and there's even a $1M USD prize for the sharp cookie here in the ML forum who figures it out.

 

[Griz44Mag]

So now I have to ask the question already asked or stated here earlier.
Is any of this advanced physics going to be put to any useful purpose by any member here?
Or are we going to go out and shoot our muzzies exactly the same as we have been doing for the last 500 years?
Load - point - shoot - repeat...........adjust aim as required.

I have shot my .54 Lyman out to 500 yards using data from the ballistics calculator.
Although I did not hit the man sized silhouette at 500 yards - I did get close enough to take out the horse he could have been riding on.
.

That's 42.5' elevation.

 

[rdlowe]

So now I have to ask the question already asked or stated here earlier.
Is any of this advanced physics going to be put to any useful purpose by any member here?
Or are we going to go out and shoot our muzzies exactly the same as we have been doing for the last 500 years?
Load - point - shoot - repeat...........adjust aim as required.

Is the answer to that question important to you? How important, if so?