Rev fire numbers

[riseball]

I was evaluating two pitchers side-by-side ... one pitcher was faster than other based on the Rader reading, but the other pitcher was faster based on the Revfire readings. Same catcher ... same pitching area ... same person using the instruments. Release point for each pitcher looked to be the difference.

Using the radar readings you might prefer pitcher-a.

However the Revfire gives more of an indication of how long a hitter gets to see the ball. So while it's speed reading is incorrect, it may be actually giving you more important information.

So, everything else being equal ... do you go with the pitcher with higher radar readings or higher Revfire readings?

Which radar reading were you using?

 

[FiveFrameSwing]

I was evaluating two pitchers side-by-side ... one pitcher was faster than other based on the Rader reading, but the other pitcher was faster based on the Revfire readings. Same catcher ... same pitching area ... same person using the instruments. Release point for each pitcher looked to be the difference.

Using the radar readings you might prefer pitcher-a.

However the Revfire gives more of an indication of how long a hitter gets to see the ball. So while it's speed reading is incorrect, it may be actually giving you more important information.

So, everything else being equal ... do you go with the pitcher with higher radar readings or higher Revfire readings?

Which radar reading were you using?

The same radar gun was used for each pitcher. I don't recall the name of the radar gun ... but it wasn't a cheap unit.

 

[FiveFrameSwing]

I was evaluating two pitchers side-by-side ... one pitcher was faster than other based on the Rader reading, but the other pitcher was faster based on the Revfire readings. Same catcher ... same pitching area ... same person using the instruments. Release point for each pitcher looked to be the difference.

Using the radar readings you might prefer pitcher-a.

However the Revfire gives more of an indication of how long a hitter gets to see the ball. So while it's speed reading is incorrect, it may be actually giving you more important information.

So, everything else being equal ... do you go with the pitcher with higher radar readings or higher Revfire readings?

Which radar reading were you using?

The same radar gun was used for each pitcher. I don't recall the name of the radar gun ... but it wasn't a cheap unit.

Perhaps you mean how was the radar gun set.

The radar gun was set to measure peak speed ... which generally is at release.

 

[Edy]

Just trying to add some more info to the thread

http://fisica.ciencias.uchile.cl/~gonzalo/cursos/MecanicaII-07/seminarios/AJP_MagnusEffect_59.pdf

I'm reproducing the table II from the study regarding maguns effect in baseballs (page #4).

TABLE II, curving of baseballs in play

================================
Speed____Spin_____Turns_____Curve (lat. def.)
ft/sec____rev/sec___in 60 ft____inches in 60 ft
================================
75________20______16_________10.8
75________30______24_________16.7

100_______20______12_________11.7
100_______30______18_________17.5

125_______20______9.6_________11.4
125_______30______14.4________16.5

150_______20______8___________11.6
================================

I haven't read the whole article so I'm just trying to dig some basics from the tests results.
Considering that the air speed is critical to create the magnuns effect, it was pretty obvious to me that increasing the speed would also increase the movement, given the RPS hasn't changed. I was dead wrong.

If you double the speed of the ball and keep the same RPS, you'll increase the movement by only 7.4%.
Conversely, by increasing the spin in 50% (20 - 30 rps) you can also increase the movement in ~55% (taking the 75 ft/sec example).
This effect tends be less sharp as the speed goes up (in the 125 ft/sec example the movement increased 44%)

 

[riseball]

Perhaps you mean how was the radar gun set.

The radar gun was set to measure peak speed ... which generally is at release.

My question exactly. FWIW - the difference between the release and final speed is pretty useful in evaluating the pitchers.

 

[Rocketech1]

I pulled up the NFCA Pennsbury Invitational Camp players results for 2013 and of the approximately 110 pitchers, as a group they averaged 17/18 RPS for all pitches. Only about 20 pitchers could achieve a 20+ RPS on any pitch. I know Pennsbury is a more academic focus but these numbers are not overwhelming by any means.

Anyone have any experience or information they can share about Pennsbury?

 

[Sparky Guy]

It makes sense that there are less RPS measured on the RevFire with increased speed due to the fact there is less time for the ball to rotate. However, I'm unable to figure out if the ball is rotating at the same speed, what is the drop in measured RPS on the Revfire given an increased velocity. Anyone?

The RevFire does not work that way. The sensor that measures the spin rate is not affected by the speed of the ball. Whether the ball is traveling 50 mph or 65 mph makes no difference. It only measures spin rate per second. It performs a rough calculation based on time and the distance you select in the hand-held receiver from when the ball starts to spin and when it stops spinning when caught. As RB stated it is not intended to be an highly accurate measurement of speed. Rather, it gives you a close approximation of
speed.

From the RevFire web site: Speed reading is based on the ball's time of flight over the standard pitching distance selected by the user.

When I got mine I was playing with it trying to see how much spin I could generates just spinning the ball using a riseball spin without throwing it. I thought I was doing pretty good when I hit 17. My DD comes home from work and asked to try it. ICE COLD without having pitched competitively for over 6 years she hit 24 on the first try. Yeah... I hung my head in shame.

 

[SoGASoftball]

My question exactly. FWIW - the difference between the release and final speed is pretty useful in evaluating the pitchers.

Are you saying that a pitch released at 60 and crosses the plate at 57 indicates a difference in pitch effectiveness than a pitch released at 60 and crosses the plate at 55? How did you measure this?

 

[riseball]

Are you saying that a pitch released at 60 and crosses the plate at 57 indicates a difference in pitch effectiveness than a pitch released at 60 and crosses the plate at 55? How did you measure this?

Yes. Higher end guns provide both readings. Spin creates drag. Drag results in deceleration. To your point a difference of 8-12 mph is usually a pretty good pitch.