rev rate question

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deadpin6
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Posts: 86
Joined: March 17th, 2016, 1:53 pm
THS Average: 190
Positive Axis Point: 4 7/8 UP 1 1/16
Speed: 16.5 at pin deck
Rev Rate: 250
Axis Tilt: 25
Axis Rotation: 60
Location: New Braunfels Tx

rev rate question

Post by deadpin6 »

Hello all,
Well I had that thought that i had calculated my rev rate at 220 but I came across a formula that requires the # of rev in the first 10 frames divided by 10 x30 x60. Now what I figured out was my phone camera is shooting at 15 frames per second so replaceing the 30 with 15 gives me 136 rev rate. But it to count total revs from release to the head pin is 220. So which is more accurate the 136 or the 220. I do know the the ball adds revs at the break point so that would be actually adding revs that was not generated at the release correct.
W.C
Pap 4 7/8 up 1 1/16
AT 25
AR 65
Speed 15.5- 16 @ monitor
RR 250
MWhite
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Re: rev rate question

Post by MWhite »

deadpin6 wrote:Hello all,
Well I had that thought that i had calculated my rev rate at 220 but I came across a formula that requires the # of rev in the first 10 frames divided by 10 x30 x60. Now what I figured out was my phone camera is shooting at 15 frames per second so replaceing the 30 with 15 gives me 136 rev rate. But it to count total revs from release to the head pin is 220. So which is more accurate the 136 or the 220. I do know the the ball adds revs at the break point so that would be actually adding revs that was not generated at the release correct.
The rev rate of interest is what YOU do to the ball, not what the lane does to the ball.

Not clear how you go from 220 to 136 just by changing the frame rate factor from 30 to 15 fps.

I'm assuming your # of revs in the 10 frames was about 1.25

10 frames at 30 frames per second is 1/3 of a second

1.25 / (1/3) gives a rev rate of 3.75 revs per second

3.75 * 60 gives a rev rate of 225 revs per minute.

Since your camera only recorded at 15 frames...

10 frames at 15 frames per second is 2/3 of a second

1.25 / (2/3) = 1.875

1.875 * 60 = 112.5

Personally I would want to recheck the original measurement, the 1.25 revs within 10 frames, it seems likely to be too low.

Also you said the phone camera records at 15 fps, but is that consistent under any kind of usage, and battery level?
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bowl1820
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Re: rev rate question

Post by bowl1820 »

Here go to this old site and punch in 15 fps and the other required info and it will tell you the Speed & RPM.

https://web.archive.org/web/20131108003 ... Calculator


There's a newer site but it doesn't go as low as 15fps
http://www.bowlingitrc.com/tools/
"REMEMBER, it isn't how much the ball hooks, it's where."
deadpin6
Member
Member
Posts: 86
Joined: March 17th, 2016, 1:53 pm
THS Average: 190
Positive Axis Point: 4 7/8 UP 1 1/16
Speed: 16.5 at pin deck
Rev Rate: 250
Axis Tilt: 25
Axis Rotation: 60
Location: New Braunfels Tx

Re: rev rate question

Post by deadpin6 »

That makes sense MWhite. Though watching my ball go down the lane it looks like more revs than what is actually there. I have found an app that i can set the fps so going to try that next practice then i have to use another to show it frame by frame. The rev count for ten frames was 1.5 which has me at 270 but seeing it it travel down i just dont think the 270 it accurate. Originally i had ran the video 5x slow and counted them from release to the head pin is where i obtained the 220. Based on a recomendation for calculating your rev rate. I can force the revs on the ball but then my accuracy goes out the window. At this point for me i know I'm speed dominate but as i work to increase a controlable rev rate i still need to be accurate on how i obtain it. Thanks
W.C
Pap 4 7/8 up 1 1/16
AT 25
AR 65
Speed 15.5- 16 @ monitor
RR 250
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