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 Post subject: Question about measuring rev rate
 Posted: Tue Nov 27, 2018 3:42 pm Post Number: #1 Post
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I've read some conflicting things about measuring rev rate and am hoping for some clarification.

I took a piece of first aid tape and put it on the ball from just above my fingers to the NAP which crosses my track and made a thumping for each revolution. I threw my ball and recorded it on my phone, then took the sound file and opened it on my pc with some audio editing software where I could measure in milliseconds the time between the thumps.

I was consistently 180 off the hand from foul line to arrows. But at the pin deck it varied from 225 to 300 depending on whether the ball tipped over and went into a forward roll (300) or not (225 which resulted in poor carry of corner pins).

So in order to report my rev rate to get layout advice, which number do I use?


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 Post subject: Re: Question about measuring rev rate
 Posted: Tue Nov 27, 2018 4:02 pm Post Number: #2 Post
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The number off the hand is used in selecting layouts. As the ball slows down and goes into its roll the RPMs increase as you've seen on the back end. -- JohnP


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 Post subject: Re: Question about measuring rev rate
 Posted: Sun Dec 02, 2018 12:00 am Post Number: #3 Post
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Always count the revs off the hand. That is what the player imparts on the ball. Everything else is effected by other parameters (ball core, lane, lane oil, ball surface).

Weird way you chose there to measure them though. I hadn't thought to use sound instead of sight to do it. I think using sound is more tricky.


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 Post subject: Re: Question about measuring rev rate
 Posted: Mon Dec 03, 2018 2:41 am Post Number: #4 Post
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Once you take the sound file and open it up in audio editing software like Waveflow you can see the waves graphically and see the thumps as spikes on the chart. You can measure the spikes in 12 millisecond increments. I don't know of a more accurate way to measure that with a video camera. I don't know whether the tape on the ball has any effect on rev rate, but if it does I'm guessing that it's not much. Of course it helps if they're not playing music at the bowling alley.


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 Post subject: Re: Question about measuring rev rate
 Posted: Mon Jan 07, 2019 12:08 am Post Number: #5 Post
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From the numbers you are giving, there could be some error. The gap between them is a bit too big. When measuring the whole lane the RPMs are more . But they are not the true RPMs the player has.

In our alleys here there is so much noise i don't know if i would be able to single out the "thumps" on an app.

In any case try it without tape that contacts the lane, and with the regular method, i think it is the safest way.


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 Post subject: Re: Question about measuring rev rate
 Posted: Mon Jan 07, 2019 2:46 am Post Number: #6 Post
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TheJesus wrote:
In our alleys here there is so much noise i don't know if i would be able to single out the "thumps" on an app.


You won't know unless you try it and compare it to the standard method using a high speed video camera.

There was a tournament last year where Hoskins made the step ladder finals. You can hear the engraved logo of his ball when it tracks over the lane. When I get some time I will record this and post the wave file.


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 Post subject: Re: Question about measuring rev rate
 Posted: Tue Feb 12, 2019 1:53 pm Post Number: #7 Post
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Today when everybody basically have a small computer on their pocket it should not be so hard to determine the rev's. Here is the way that I use to quickly calculate the revs on the lane:

I normally use slow motion camera (120fps) on my phone/tablet. It is possible to use "normal" frame rates also, but it is easier with slow motion.

Put a piece of white tape close to pap, then throw the ball and film the shot. With the Hudl Technique app (ex-ubersence, free program) I can rewind the video to the point where the ball exit from hand. I can then tap the video timer and it will reset the timer to 0.00s (for some reason this does not work in my Ipad anymore but it is not a problem). Then I'll forward the video until there has been three full revolutions, measure the time and calculate the revs.

Formula for this calculation is: 60/(Xseconds/revs)
Example using three revolutions in 0.56s: 60/(0.56/3)=321RPM

Even when done quickly I can easily measure time at least within 0.02s margin of error and I've found it accurate enough. 0,02s in the 300RPM range means about 10revs.

_________________
Right Handed
PAP 4 3/8" x 0"
60* rotation
17.5* tilt
320-360 rev rate
17mph off hand


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