Demarini Vendetta Bat

[Dave Reed]

Well, it's a little slow here on a Friday night, so.....

A couple of pages back, dash_riprock suggested that adding holes to the Reebok bat was silly. MTD. Sr. took him to task, asserting that dash hadn't learned fluid mechanics. dash invited MTD to provide a calculation of drag, but instead got a (wrong) explanation of ball-bat collisions.

Dash was right-- there is little benefit to adding holes to the bat handle. The drag on a cylinder is proportional to the area times the velocity squared. Since the handle moves roughly at 1/3 the speed of the barrel, and the area is perhaps 1/10 that of the barrel, in rough terms the air resistance of the handle is about 1% that of the barrel. Reducing that 1% to perhaps 0.8% is a very small effect.

And the ball-bat collision stuff? MTD starts with the assertion that the collision is elastic. But it isn't. A baseball has a coefficient of restitution of around 0.45 at typical collision velocities, and is limited by rule to 0.565 at 60 mph (less than bunting speed). All the subsequent discussion of conservation of energy and momentum, and sums of velocities is inappropriate for inelastic ball-bat collisions.

Finally, this assertion: "The mass of the bat is much greater that the mass of the ball and it only takes a small increase in a bat's velocity to greatly effect the amount of momentum transfered from the bat to the ball." is way wrong.

If the collision were elastic, a 1 mph increase in bat speed would give a 2 mph increase in ball exit speed. But since the COR is about 1/2, the actual effect is 1 mph in bat speed gives about 1 mph in ball exit speed.

[UmpJM]

Originally Posted by Dave Reed

Well, it's a little slow here on a Friday night, so.....

A couple of pages back, dash_riprock suggested that adding holes to the Reebok bat was silly. MTD. Sr. took him to task, asserting that dash hadn't learned fluid mechanics. dash invited MTD to provide a calculation of drag, but instead got a (wrong) explanation of ball-bat collisions.

Dash was right-- there is little benefit to adding holes to the bat handle. The drag on a cylinder is proportional to the area times the velocity squared. Since the handle moves roughly at 1/3 the speed of the barrel, and the area is perhaps 1/10 that of the barrel, in rough terms the air resistance of the handle is about 1% that of the barrel. Reducing that 1% to perhaps 0.8% is a very small effect.

And the ball-bat collision stuff? MTD starts with the assertion that the collision is elastic. But it isn't. A baseball has a coefficient of restitution of around 0.45 at typical collision velocities, and is limited by rule to 0.565 at 60 mph (less than bunting speed). All the subsequent discussion of conservation of energy and momentum, and sums of velocities is inappropriate for inelastic ball-bat collisions.

Finally, this assertion: "The mass of the bat is much greater that the mass of the ball and it only takes a small increase in a bat's velocity to greatly effect the amount of momentum transfered from the bat to the ball." is way wrong.

If the collision were elastic, a 1 mph increase in bat speed would give a 2 mph increase in ball exit speed. But since the COR is about 1/2, the actual effect is 1 mph in bat speed gives about 1 mph in ball exit speed.

Oddly, I think I actually understood (sorta' ) what Dave Reed said here, and found his argument compelling.

Nicely done.

JM

[Emperor Ump]

We got this in an email from our state high school association dated 2/6:

Rule- Compliant Bats

The following bats are compliant for use in VHSL contests:

The Mattingly Bat
The Demarini Vendetta
The Reebok Vector O

This will also be sent in Weekly Update.

So in a week and a half they have changed their minds from the state clinic where they spent a few minutes talking about the bats and even brought in the Vendetta so we all knew what it looked like.

Give it a few weeks and it will change again.

[Tim C]

I received the following e-mail from Eliot Hopkins of the NFHS today. The NFHS sent this e-mail to all SRIs in all FED states baseball programs.

The following bats are deemed LEGAL for use by the NFHS:

1) DeMarini Vendetta
2) Reebok Vector O
3) NIKE Aero Fuse

This pretty much closes the book in Oregon.

Regards,

[Steven Tyler]

Originally Posted by Tim C

I received the following e-mail from Eliot Hopkins of the NFHS today. The NFHS sent this e-mail to all SRIs in all FED states baseball programs.

The following bats are deemed LEGAL for use by the NFHS:

1) DeMarini Vendetta
2) Reebok Vector O
3) NIKE Aero Fuse

This pretty much closes the book in Oregon.

Regards,

Don't forget about the Mattingly bat. It is also legal for use in FED.

[socalblue1]

Last I heard the new version DeMarini bat had not yet received a BESR rating, though it was diue shortly. From What Tim C posted looks like it was all worked out.

IMO if Fed & NCAA both say OK no reason why other non-pro leagues should have an issue.

[Rich Ives]

FED has posted the official answer on their web site. The memo is dated Feb 5.

http://www.nfhs.org/web/2009/02/revi...ball_bats.aspx

[ozzy6900]

Originally Posted by Tim C

I received the following e-mail from Eliot Hopkins of the NFHS today. The NFHS sent this e-mail to all SRIs in all FED states baseball programs.

The following bats are deemed LEGAL for use by the NFHS:

1) DeMarini Vendetta
2) Reebok Vector O
3) NIKE Aero Fuse

This pretty much closes the book in Oregon.

Regards,

Which is what I stated in my original post. What I do not understand, Tim, is how can a State change this rule?

[BretMan]

Originally Posted by ozzy6900

Which is what I stated in my original post. What I do not understand, Tim, is how can a State change this rule?

FED baseball rule book, page one:

"Member associations of the NFHS independently make decisions regarding compliance with or modification of these playing rules for the student-athletes in their respective states."

States are free to modify, adopt or ignore any rule as they see fit. So, yes, they can do it. That doesn't always mean it's clear why they do it, or that doing it is the best solution.

[TxUmp]

Originally Posted by Tim C

I received the following e-mail from Eliot Hopkins of the NFHS today. The NFHS sent this e-mail to all SRIs in all FED states baseball programs.

The following bats are deemed LEGAL for use by the NFHS:

1) DeMarini Vendetta
2) Reebok Vector O
3) NIKE Aero Fuse

This pretty much closes the book in Oregon.

Regards,

When I check the NFHS site, #3 is not listed. Did you get a different memo that what is posted on the NFHS site? Is NFHS deliberately trying to muddy the waters?

[JJ]

(no pun intended - I'm referring to the bat)

The DeMarini Vendetta bat, as of today, is now LEGAL in Illinois. This is a change from the original Illinois High School Association ruling. The online rules interp meeting will now also reflect this change.

The Reebok Vector O is still ILLEGAL in Illinois.

JJ

[Steven Tyler]

I saw a Reebok Vector 0 yesterday. It doesn't look as if it should be made illegal. it was properly stamped BESR.

[bob jenkins]

Originally Posted by JJ

(no pun intended - I'm referring to the bat)

The DeMarini Vendetta bat, as of today, is now LEGAL in Illinois. This is a change from the original Illinois High School Association ruling. The online rules interp meeting will now also reflect this change.

The Reebok Vector O is still ILLEGAL in Illinois.

JJ

Why is the Vector ILLEGAL if the FED has said it's legal? (I know -- the handle isn't a cylinder. I guess the question is why has IL chosen to "override" the FED in this case? You can respond off-line if you'd like.)

[johnnyg08]

so basically we're still looking for the BESR stamp right?

[Rich Ives]

So does anyone really know if the state reps were acting on their own in the initial assessment or did FED really cross them up?