[russc]

What's it at when you hit 15 feet? 270ish? I'm trying to convince the local field to drop the confusing mercy rule and just lower overall FPS from 300, seeing as they want to be renter friendly.

[Leafy]

russc, on Apr 1 2009, 12:47 AM, said:

What's it at when you hit 15 feet? 270ish? I'm trying to convince the local field to drop the confusing mercy rule and just lower overall FPS from 300, seeing as they want to be renter friendly.

but i love getting people to surrender. especially groups of 3 while pumpin it.

[Texas Cheezburgr]

russc, on Mar 31 2009, 11:47 PM, said:

What's it at when you hit 15 feet? 270ish? I'm trying to convince the local field to drop the confusing mercy rule and just lower overall FPS from 300, seeing as they want to be renter friendly.

The overall speed is not really slowed that much at all. Just gravity pulling it down.

[UV Halo]

cockerpunk, on Mar 30 2009, 05:48 PM, said:

note under the assumptions it is listed as zero barrel angle.

obviously we had to elevate the gun to get it to hit the chrono at range. but remember, we are dealing with ranges and assumptions about the ranges of values. the extrapolated data is part of an ongoing project i have with viper the scenario producer.

By "elevate" do you mean you incline the barrel upwards or, raised the height of the gun/stand? If you did increase the inclination, did you measure how much so and was the inclination the same between the 50ft and 100ft tests? What was the height of the breach?

I took the time to create some google spreadsheets of the predicted numbers from the paintball trajectory calculator. Upon comparing them to the test data, I found some interesting things:

Looking at the 50ft Ranged test, 286 is the most frequent muzzle velocity with three shots. As you can see below, the predictions at least approximately hold true when compared to the average and measured velocities:

48.69ft @ 207.4fps
50ft @ 203.6fps (205, 204, 202)
58.71ft @ 194.2fps

Looking at the 100ft Ranged test, 299fps is the most frequent muzzle velocity with four shots. But, in this case, the predictions only holds true for one of the shots:

100ft @ 160.3fps (157, 160, 165, 159)
96.37ft @ 158.7fps
104ft @ 151fps

[EDIT]: I blew away my question about 40ft as I see Leafy was referring to the extrapolated data and not reality.

This post has been edited by UV Halo: 08 April 2009 - 09:34 PM

[cockerpunk]

its not too bad though ... interesting ...

the extrapolated data is a bit of my fun time, im not sure how realistic it is though, might need to compensate for the launch angle to do it.

[russc]

Texas Cheezburgr, on Mar 31 2009, 11:48 PM, said:

russc, on Mar 31 2009, 11:47 PM, said:

What's it at when you hit 15 feet? 270ish? I'm trying to convince the local field to drop the confusing mercy rule and just lower overall FPS from 300, seeing as they want to be renter friendly.

The overall speed is not really slowed that much at all. Just gravity pulling it down.

Nope. You're wrong on that one.

I tested a 295-300 fps shot at 15 feet. Initial over a yellow chrono, second chrono was a red one. I made sure they were both reading approximately the same speeds.

At 15 feet, the 300fps shots had dropped to about 255-260. With that info I managed to convince the owners to drop the surrender rule and go to an overall speed of 275. 270-275 drops to 255-260ish at about 2-3 feet.

This post has been edited by russc: 08 April 2009 - 11:45 PM

[brycelarson]

yeah Russc - the faster a projectile is moving the faster it decelerates. It's not a linear thing.

[cockerpunk]

indeed, drag is modeled as a square often, but for some flows a better approximation is to the fourth.

means when you go faster, your drag force increases ALOT faster then your velocity.

thats why i curve fit to an exponential and not a line.

[Snipez4664]

Although I believe that in the regime we're in for a sphere its pretty much a square relationship? There are some Cd effects after the wake separation in back changes (at what, Re=~50k OTOH?) but those actually push back towards linear IIRC.

I don't recall what fit you used, but 2nd order or maybe 3rd would be fine. Less physical analogue the higher you go though.

"How many parameters to fit your equation to this elephant?"

[NECanes Coach]

Awesome test.

Have you tried/considered shooting various guns to see if there is any difference in the behavior?

[Leftystrikesback]

NECanes Coach, on Apr 10 2009, 12:55 PM, said:

Awesome test.

Have you tried/considered shooting various guns to see if there is any difference in the behavior?

The only gun there will be a difference in would be one that spins the ball significantly (apex, flatline... maybe backspin bolt? ). The spin mostly affects lift on the ball, but it would be interesting to see if anything happens to velocity with those barrels.

[cockerpunk]

NECanes Coach, on Apr 10 2009, 03:55 PM, said:

Awesome test.

Have you tried/considered shooting various guns to see if there is any difference in the behavior?

yes, what guns would you like to see?

when we pull this rig out again for the first strike rounds, we can probably do a few other guns too. what would you like to see?

[brycelarson]

cockerpunk, on Apr 10 2009, 03:51 PM, said:

NECanes Coach, on Apr 10 2009, 03:55 PM, said:

Awesome test.

Have you tried/considered shooting various guns to see if there is any difference in the behavior?

yes, what guns would you like to see?

when we pull this rig out again for the first strike rounds, we can probably do a few other guns too. what would you like to see?

I'm going to guess that poppet v spool will be the answer - so I suggest Ion / SP1 vs cocker vs emag.

I know that all of those guns will be present at our next testing anyway.

[cockerpunk]

maybe i can get that shoebox shocker back and really put that one in the ground.