For those interested heres a Video of a 550 RPM release for comparisons.
This is a release of a 550 RPM bowler that uses his thumb. Normal speed video is followed by high speed footage.
I think Dog is close, (not that you manipulated it intentionally).Originally Posted by Mike White
Your right that the 1.8 sec in the video you posted is 54 frames (I counted them), but it's 54 frames in a 30FPS video which is not the same as 54/480.
(Note: a guy over on ballreviews had done the same thing quite a while back. And said he found it did throw off the accuracy of the rev rate. So it does sound like it is possible.) I'm not saying it going to be off a lot.
If you used a video shot at 30FPS it doesn't matter if one rev will not have completed after 3 frames, because using the usual Calculating Rev Rate formula is based on 10 frames.If I record at 30 fps, one rev will not have completed after 3 frames, but will have gone beyond a rev after 4 frames.
Using the info you just gave, that you have a little more than 1 rev in 4 frames (in a video shot @30FPS).
We'll say you got 2.5 to 2.75 rev's in 10 frames, that would give you 450 to 495 revs. Which is still quite respectable! So props to you there.
Now if you got 3 full revs in 10 frames, you'd have your 533 then.
Shoot give it a shot, make another video. Just shoot it at 30FPS, put a Tracer tape on it and see what you get. Doesn't hurt to have a updated video of your release. (OH and try not to drill a hole in the lane with that bounce)
Right handed Stroker, high track ,about 13 degree axis tilt. PAP is located 5 9/16” over 1 3/4” up.Speed ave. about 14 mph at the pins. Medium rev’s.High Game 300, High series 798
"Talent without training is nothing." Luke Skywalker
For those interested heres a Video of a 550 RPM release for comparisons.
This is a release of a 550 RPM bowler that uses his thumb. Normal speed video is followed by high speed footage.
Last edited by bowl1820; 12-14-2014 at 11:55 AM.
Right handed Stroker, high track ,about 13 degree axis tilt. PAP is located 5 9/16” over 1 3/4” up.Speed ave. about 14 mph at the pins. Medium rev’s.High Game 300, High series 798
"Talent without training is nothing." Luke Skywalker
I shoot all my videos at normal speed. I may slow them down 50% or 25%…but at normal speed I can at least roughly calculate the time it takes for the ball to travel 60ft. So if I know it's traveling at a certain speed over a given time…I can then see how many times it "revolved" and can calculate the rpms. If I slow the video down 50%, I have to adjust the final number x2 (or x4 if I slow it to 25%).
In you video…I know it traveled 60ft. I know it revolved 20 times (which is substantial). What I don't have is an unadulterated TIME…so I can't calculate a true speed nor rev rate. IF we use a speed from previous footage I have of you…it's about 16.4mph. Using THAT speed, a ball that revolves 20 times before hitting the pins will have a rev rate of just shy of 480rpms.
That is what I would calculate your rev rate, at least what it was at the AVI Challenge in Vegas.
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Ball Speed: 14.7mph; Rev. Rate: 240rpm || High Game (sanc.) = 300 (268); High Series (sanc.) = 725 (720); Clean Games: 198
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When recording at 480 fps each frame represents 1/480 seconds of real time.
54 frames represents 54/480th of a second.
The fact that it is being played back at 30 fps doesn't change the amount of real time that transpired during those 54 frames.
When played back at 30 fps, it took 1.8 seconds to complete those 54 frames, had it played back at 60 fps, it would have taken 0.9 seconds to complete the playback.
None of that effects the recording.
I would show you a gap of 160 frames, the equivalent to your 10 frames at 30 fps, but by the time it reaches 160 frames, the ball is fuzzy and the thumb hole can't be clearly determined.
The 10 frame at 30 fps is one method, not the only method, Counting 54 frames for 1 revolution is just as accurate, if not more so.
54/480 = 0.1125
60 / 0.1125 = 533.33333
Counting frames for one revolution at 480 fps is twice as accurate as counting revs in 10 frames at 30 fps assuming you count revs in 45 degree increments.Code:FC Rev Rate RC Rev Rate 48 600.00 4 720.000 49 587.76 3 7/8 697.500 50 576.00 3 3/4 675.000 51 564.71 3 5/8 652.500 52 553.85 3 1/2 630.000 53 543.40 3 3/8 607.500 54 533.33 3 1/4 585.000 55 523.64 3 1/8 562.500 56 514.29 3 540.000 57 505.26 2 7/8 517.500 58 496.55 2 3/4 495.000 59 488.14 2 5/8 472.500
Using the full lane is usually not a good idea, because for most people, lane friction will slow the ball down, and increase the later rev rate.
What is important is the rev rate as it leave the hand (i.e. the bowlers rev rate) not the net effect of bowler, lane friction, and ball friction.
I put that shot into iMovie again, and made a clip from the moment the ball hit the lang, until the first frame the head pin moved.
iMovie says the duration is 38.1 seconds when played back at 30 fps.
38.1 / 16 = 2.38125 seconds = 17.18 mph
20 revs over 2.38125 seconds would average 503 rpms
I have a question on determining rev rate. If you axis tilt is larger meaning track is lower, then the ball will be able to rotate more correct? Then when determining your rev rate does that factor in?
Last edited by fortheloveofbowling; 12-14-2014 at 04:42 PM.
Great point! I'm really not sure when and if the axis tilt is factored in, but it certainly should be. You can drop the ball with your hand on top and throw it like a top to achieve a high rev rate. The question is, does rev rate alone knock down pins? I don't think so. The ball also needs to roll before it hits the pins. If it doesn't, it will carry light hits, but leave corner pins on solid pocket hits all day. In the end, it's how many pins you can knock down and who you can beat, and who can beat you.
Another thing about rev rate as well is the ball you are throwing. We all have different types of balls, some that rev up earlier and some that have more of a mid lane or even later. If you are counting the revolutions a ball makes as it goes down the lane this can vary significantly depending on the ball and drilling. Rev rate is obviously helpful a lot of times but it as rob said it is about knocking down the pins in the end.
You have the info about a ball not quite rolling backwards.
If the ball has achieved angle of entry, but has not fully gone into the roll phase, light pocket carry is crap.
Flush pocket carry is good.
Carrying the 1-2-4-7 out of a full rack is all about location.
If you hit the head pin in the right place (flush pocket), the ball can be thrown dead and carry those 4.
You do need the proper angle of entry to go from that location to the next important location which is where the 3 is driven directly towards the 10 pin.
You can't throw the ball dead and go from the first location (driving the 1 towards the 7) to the second location (3 -> 10) because the ball will deflect to the right too far.
If you have the ball hit light (breaking the direct 1-2-4-7 chain) you're relying on luck to carry those 4.
In the 14-15-16 # video recently posted, you see the 15 # ball hits light enough that the 1-2-4-7 chain is broken.
The 4 pin is not driven into the 7 like it is for the 14, and 16 # ball.
The tilt doesn't matter, other than how effective those revs might be.
With low tilt, the force you apply on the ball is in an up direction, where as in a high tilt, the force is more in a forward motion.
You have more leverage lifting up, than pushing forward.
In the modern ball, you can still lift up, but you need to control the axis of rotation otherwise the ball will jump left when exiting the oil.
With a lower rev release, when the ball exits the oil, the axis of rotation will turn forward and roll. While the rotation is turning, the ball is hooking, once the rotation is in line with the balls path, there are no more forces to change the balls path so it enters the roll phase.
With my release (about 45 axis rotation) the ball doesn't turn forward much, the ball maintains most of that axis rotation, and overachieves the angle of entry.
The high rev rate also reduces the "push" as the ball exits the oil, so you get the worst of both worlds, ball hooks too sharp, and too early.
I use urethane to achieve a less efficient reaction between the ball and the lane, resulting in a lower angle of entry (still more than 6 degrees), and more "push" as the ball exits the oil.
A high tilt ball will result in higher rev rate in the back ends due to the interaction between the lane and the ball.
The smaller the track (due to tilt) the faster the ball needs to rev for it to achieve the roll phase.
That extra rev won't be in the ball just after release.
The rev rate off the hand is a function of the force your fingers apply to the ball, and the RG value of your PAP.
Last edited by Mike White; 12-15-2014 at 01:14 AM.
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