Bullet Spin

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May 15, 2008
1,913
113
Cape Cod Mass.
I watch a lot of baseball. I can't seem to help myself, I watch my NY Mets blow games on a regular basis. One thing sticks out and puzzles me, bullet spin. The slider is a big part of a baseball pitcher's arsenal and it is basically bullet spin. The slider breaks late, down and away to a pitcher's glove side. How does bullet spin break? I did some research and found an explanation that explains the break and why it occurs 'late'.
Everyone knows what bullet spin is: the spin axis is horizontal and pointed in the direction that the ball travels, the magnus force is distributed evenly around the ball thus there is no break. However as the ball slows down it's trajectory changes significantly in a downward direction, yet the spin axis remains horizontal. As the ball 'sinks' the air flow changes, there is more contact with the 'bottom' of the ball and this generates enough magnus force to cause the ball to break. Imagine throwing a football where the spin axis remains horizontal for the whole distance, as the ball loses speed and starts to fall it will drift to the left (for a right hander).
How does this apply to softball? If you want a curveball with a lot of late break don't throw it with perfect horizontal spin, you need to tip the axis up a little so that as it loses speed the spin will line up with the change in air flow and there will be more magnus force. Half bullet, half curve, or something close to that should do it.
 
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Nov 30, 2018
359
43
Marikina, Philippines
The axis is tilted not . You can even make a softball move down and in with finger index or index/middke-finger pressure. The 100% bullet spin would be rotating 100% perpendicular to the pitch direction. The spin is angled off the flight direction 20-30° is my guess.
 

radness

Possibilities & Opportunities!
Dec 13, 2019
7,270
113
I watch a lot of baseball. I can't seem to help myself, I watch my NY Mets blow games on a regular basis. One thing sticks out and puzzles me, bullet spin. The slider is a big part of a baseball pitcher's arsenal and it is basically bullet spin. The slider breaks late, down and away to a pitcher's glove side. How does bullet spin break? I did some research and found an explanation that explains the break and why it occurs 'late'.
Everyone knows what bullet spin is: the spin axis is horizontal and pointed in the direction that the ball travels, the magnus force is distributed evenly around the ball thus there is no break. However as the ball slows down it's trajectory changes significantly in a downward direction, yet the spin axis remains horizontal. As the ball 'sinks' the air flow changes, there is more contact with the 'bottom' of the ball and this generates enough magnus force to cause the ball to break. Imagine throwing a football where the spin axis remains horizontal for the whole distance, as the ball loses speed and starts to fall it will drift to the left (for a right hander).
How does this apply to softball? If you want a curveball with a lot of late break don't throw it with perfect horizontal spin, you need to tip the axis forward a little so that as it loses speed the spin will line up with the change in air flow and there will be more magnus force. Half bullet, half curve, or something close to that should do it.
Good read!
Think you added the answer with the explanation!
Big Q pin pointed reason on movements.
The axis is tilted not . You can even make a softball move down and in with finger index or index/middke-finger pressure. The 100% bullet spin would be rotating 100% perpendicular to the pitch direction. The spin is angled off the flight direction 20-30° is my guess.

Read at times people frown on bullet spin.
Really spin ( any spin ) creates an element batters have to contend with.
Different spins can create illusion even without much movement.

Drop spin is easiest for my hitting decision.
In compairison...
Riser and bullet spin are less
discernible from each other.
 
May 23, 2015
999
63
In baseball you have the mound, distance to work,, and arm slot in your favor. Thats why a slider works in baseball not necessarily in softball. A slider is a happy place between a curve and fastball. Throwing overhand allows a lot more manipulation of the ball trajectory
 

radness

Possibilities & Opportunities!
Dec 13, 2019
7,270
113
Its just variety of pitch locations.
And why bullet and a drop spin add extra element to fastpitch.
Being able to do either.
 
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May 16, 2016
1,024
113
Illinois
All I have to say is when my daughter throws a pitch that has bullet spin, the ball comes in very straight. Why would you want a ball to come in straight? Bullet spin does not seem like the ideal way to spin the ball if you want to be a good pitcher.
 

radness

Possibilities & Opportunities!
Dec 13, 2019
7,270
113
All I have to say is when my daughter throws a pitch that has bullet spin, the ball comes in very straight. Why would you want a ball to come in straight? Bullet spin does not seem like the ideal way to spin the ball if you want to be a good pitcher.
How old? Trying to or no?

Caught for a pitcher name
Cindy Bird
We called her "mama bird"
Shew threw a hard bullet spin.
Used it as an inside pitch.
Almost never came up in the zone.
Direct and to the point.
Comming at you!
*She threw it hard, noticeably.
 
May 16, 2016
1,024
113
Illinois
How old? Trying to or no?

Caught for a pitcher name
Cindy Bird
We called her "mama bird"
Shew threw a hard bullet spin.
Used it as an inside pitch.
Almost never came up in the zone.
Direct and to the point.
Comming at you!
*She threw it hard, noticeably.


Daughter is 12u.

No, we never try to throw bullet spin on purpose.
 

sluggers

Super Moderator
Staff member
May 26, 2008
7,132
113
Dallas, Texas
@Gambler Bob and @RADcatcher , Rachel Garcia doesn't know how to pitch? Dallas Escobedo throws the same rise.

The physics is pretty simple--it is the same as a boat rudder. Throw the ball so there are seams on the bottom 1/2 of the ball "into the wind" but no seams on the top 1/2 of the ball. The air is deflected by the seams on the bottom 1/2 of the ball downward, causing the ball to move up.

Garcia throws a bullet spin riseball. The NCAA conveniently has black logos on the ball near the spin axis.

It is very clear that the black label is spinning around an axis.



Here is Garcia throwing a fastball up in the zone that gets tatooed. Notice the spin axis in this pitch is in the black logo. (She was trying to throw a high inside pitch but caught too much of the plate.)



You can get see the the second pitch better at the 2:15:00 mark of this video.

 
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