drivermaker said:
Only 26 mph...Frankie is NOT a powder puff hitter. Based on what you've measured with other players and seen of the women, what do you think the top women would come out at compared to Frankie with YOUR device?
(This is what I'm getting at...the differences and discrepencies in a variety of guns)
Where do you place the unit when measuring break speed and what is the lowest that you've seen it register? Who is the manufacturer and what model is it? What other applications can it be used for...such as golf swing speed, bat speed, auto racing, pitched baseball? If you don't want to post, please PM me.
I have some statistical info at home, but from what I remember: the average male pro breaks around 24.5 MPH, and the average female pro breaks around 19.6. Taking into account the inherent erro in off-angle measurements, I would estimate that Frankie's break was actually 5% faster than the gun measured. That 26 is actually pretty good, all things considered.
FWIW, I don't think that the gun itself makes a difference, and in particular, I don't thing my device would fair better or worse against a police radar gun, or a military one. As the techonology is fairly straightforward, any radar gun will be accurate to within a MPH or maybe two, but this is less relevant than the angle you measure the from. I.e., the Cosine Effect results in two measurements that you have to account for when measuring breaks: horizontal AND vertical. Without giving the math, a 15° angle results in about a 3.5% margin of error, and a 30° angle results in about a 13% margin of error. [This is the case with any radar gun.] I use 5% since I measure from about 15° to the side and around a foot above the table as well.
When measuring speed with a radar gun, you should be as close to in front or behind the moving object as possible (on the same planes as the thing you are measuring). However, for breaks, if you stand directly behind or in front, there is a tendency for the machine to register the stick, the shooter, or even the object balls after impact. That's why I measure from 15° to the side... I aim right at the center spot and usually get an accurate reading.
To calculate the speed taking the Cosine Effect into account (at 15°), take the speed, move the decimal in one place (divide by 10) and half the number. Add this to what you started with, and that would be the adjusted speed. (i.e., if the machine shows 18, 18/10 = 1.8 and half of that is .9, so the speed would be 18.9 MPH).
If a player breaks from the side rail, and you measure from the center spot, you are at about 30°. If you are a foot or so above the table, you'll have another 2% error, so that's about 15% off. Take the reading, move the decimal, add that number and half that number to what the machine had. (i.e., if the machine shows 18, take 18 + 1.8 + .9 = 20.7).
*I always tell the shooter what the machine says without the Cosine modification...*
The one I use is a Bushnell Speedster. It measures from 10 MPH to around 200 MPH. It is designed to measure baseballs, but can be used for cars etc. For clubhead speed or baseball bat speed, you really need a chronograph as mentioned above.
If you have any other q's, let me know.
-td