[BlueShox]

I hear people asking about how they can find their velocity without chronographs all the time. I posted this a few months back, but it was deep in the middle of a thread in the Tippmann forum, so not many people saw it. So, I figured I might as well post it up and hope for a sticky.

You can measure your own velocity by yourself, with a little bit of math.

WARNING* THIS WILL GIVE YOU A ROUGH ESTIMATE ONLY *WARNING
This should, in no way, take presedence over a chronograph. If at all possible use one of those instead, for the most accurate readings possible.


First, go into your backyard. Find a target several feet away (such as a tree) from the point where your gun will be stationary. I would suggest at least 15 feet. The distance has to be in feet to get the standard velocity. Then, take a stop watch, and find the time from the second you pull the trigger to when the ball makes contact with the stationary object.

velocity=distance/time
time=distance/velocity
distance=velocity x time

The best way is to start with target velocity.
I'd say a safe place to start would be around 280.
So...
280=distance/time

Lets say the object you're shooting to is 30 feet away.
280=30/time

Time is going to be X

Now is the math part. 280=30/X
Arrange it so that X (Time) is on the left side of the equation
time=distance/velocity
X=30/280
The time it takes the paintball to travel 30 feet is .107 of a second.

The more you increase the distance, the easier it will be to caluclate
X=30/280=.107 of a second
X=50/280=.179 of a second
X=70/280=.250 of a second
X=90/280=.321 of a second
X=100/280=.357 of a second
^
^each of these measurements is distance in feet. (I wouldn't try anything more than a hundred feet, a hundred feet is always going to be highly inacurate)

It's going to take some trial and error, and it's certainly not as easy or accurate as using a chronograph, but it is possible to calculate your velocity without any technology more advanced than your brain and a calclulator.


If you have a gun thats allready set at your target velocity, then setting the velocity of all your friends is much easier.

Find an object around 20 feet away, and have all players, along with the gun chronoed (it will be known as the base gune) shoot on the count of three. If your ball hits the surface before the ball of the base guns, then lower your velocity. If it hits afterward, raise your velocity. Keep on adjusting it until all the balls are hitting at around the same time, they don't need to be exact.

Feel free to make any corrections.

[DarkTamer]

You're not taking into account air resistance. Not to mention it's impossible get an accurate enough measurement of when the ball leaves the barrel and hits the target with a stopwatch.

Next time you chrony your gun, watch the flight path and learn to recognize what it looks like. That always gets me within -+15fps of the desire speed, and then when I actually go to chrony at the field, my gun requires nearly no adjustment, maybe 1/8 of a turn at most.

You're always required to chrony your gun anyways...

[JH]

it would work for a rough estimate though. just about like your guess

[evolkers2003]

Its pry one of the closest ways to tell at a renegade feild. Its not gonna be that close but in the ballpark.

[DarkTamer]

Originally Posted by JH

it would work for a rough estimate though. just about like your guess

No it wouldn't, it's not possible to find the time accurately enough with a stopwatch, it's human error. You will inevitably be off by at least .25th of a second, which will lead to too much of a difference.

If you wanted to try and make it easier, you could increase the distance, but then the air resistance would be making too much of a difference. If you wanted to offset air resistance, you'd have to make the distance really small, but it's already far too difficult to measure the time in the first place, small distances would just be impossible.

Even if you could measure it accurately, chronographs measure the speed right when it leaves the barrel. Even if this were accurate you'd end up getting the average speed for the overall flight, which would mean the beginning speed would actually be higher than it should be. Again, you could try and offset this by doing this within... 5-10ft, but that's not possible.

If you're doing this to save time at the field... well that's kind of pointless, like I said, just eyeball it, and make the fine adjustments at the field; it only takes a minute at most anyways with guns nowadays. If you're doing this because you're playing renegadeball and don't have a chronograph, well you shouldn't be doing it without a chronograph. Have everyone chip in a bit and buy one of those cheap $70 handheld ones.

[BlueShox]

I was doing this more for the people who get five other friends to go play in his backyard kind of thing. I guess you're right with wind resistance and flight path, etc.

It would give you an extremley rough estimate. But, if you don't have anything else to measure it by, it's better than nothing.

edit: I just tried my reflexes with the stop watch, it's extremley hard to clock anything lower than .19 seconds

.25 is fairly easy, so I think anything further than that won't be too much trouble. But that's allready 70 feet, so wind resistance and other factors will cause alot of inconsistancies.

Very impractical, but like I said, better than nothing