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After years of discussion: KICK!


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#51 Troy

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Posted 03 July 2011 - 02:29 PM

im never a fan of giving up data (ie filtering before recording), there is no reason you can't capture everything and filter it later if you know how to building a filter (me and lurker were talking about a differentiation filter). the problem then i picking your corner frequency on your filter (basically slope). idk, i'll try things out next week when i have some time.


For those of us that aren't quite as mathematically proficient as you guys are, what kind of filtering are you looking to do exactly?

I know that excel is awesome and all, but it seems to me that processing large amounts of data is always easier with a database and some code.
\m/

#52 brycelarson

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Posted 03 July 2011 - 05:59 PM

Were not actually looking at that much data for this test. The software were using is only grabbing 1000 data points. The shot itself is only two or three hundred samples long.

#53 Egomaniacal

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Posted 03 July 2011 - 11:18 PM

im never a fan of giving up data (ie filtering before recording), there is no reason you can't capture everything and filter it later if you know how to building a filter (me and lurker were talking about a differentiation filter). the problem then i picking your corner frequency on your filter (basically slope). idk, i'll try things out next week when i have some time.



If the filter is low-pass you won't lose any information that's relevant to the test. All measurable effects I'm seeing there are well below 500 Hz, and it looks like your sample rate is what, 1ksps? I don't see any line hum, so that's good, but It's probably below the sensitivity of your scope or buried in all that other crap.

There is a reason you don't want to filter after you've digitized your signal. Before it goes in the 'scope, it's an analog signal so it has all frequencies, from 0 to infinity. When you digitize that signal, every one of those contributions to the signal gets stuffed into that data point. But because your sampling rate is less than infinite, you can't distinguish between signal and noise at a higher frequency. You won't be able to get rid of any noise that's at a higher frequency than half your sampling rate. And even eliminating anything close to that frequency is difficult.

As a rule of thumb, when it comes to noise the earlier you can nip it the better. And with a properly built filter, you won't be losing any information. The other thing you could try is hooking your sensor up in differential configuration instead of single-ended (just an assumption on my part that it's not already).

If I'm guessing right at what a "differentiation filter" is, I don't think you'll have much luck because the "slope" for the noise is probably less than some of the signal itself, and greater than any details you're trying to get out of the noise. All said and done it is a pretty strong signal.

What sensor are you using (model # & MFR) - I might poke around the spec sheets to see what's up.

Edited by Egomaniacal, 03 July 2011 - 11:22 PM.

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#54 Kirko017

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Posted 04 July 2011 - 04:34 AM

lol yay now the vs threads are going to be completely full of pointless arguments about kick.... because we all know paintball markers have so much dramatic kick that we have to argue about it. biggest fail this testing is going to cause.

Edited by Kirko017, 04 July 2011 - 04:35 AM.

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#55 The_Economist

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Posted 04 July 2011 - 09:36 PM

lol yay now the vs threads are going to be completely full of pointless arguments about kick.... because we all know paintball markers have so much dramatic kick that we have to argue about it. biggest fail this testing is going to cause.


Ummm they weren't full of threads about kick already? If any two people are bullshitting about guns, all they can compare anymore is efficiency, kick, ergonomics, and looks. Everything else is equal between two guns in the same price range. Efficiency can't really be argued since it is usually measured by Mike. Ergonomics and looks are completely subjective and therefore can't be argued in any rational sense. All that's left is kick, and people ask "Which gun is smoothest?" about every thirty seconds on this forum. At least this testing can provide some hard numbers for "smoothness" comparisons that were previously based completely on perceptions.


#56 cockerpunk

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Posted 04 July 2011 - 11:43 PM


im never a fan of giving up data (ie filtering before recording), there is no reason you can't capture everything and filter it later if you know how to building a filter (me and lurker were talking about a differentiation filter). the problem then i picking your corner frequency on your filter (basically slope). idk, i'll try things out next week when i have some time.



If the filter is low-pass you won't lose any information that's relevant to the test. All measurable effects I'm seeing there are well below 500 Hz, and it looks like your sample rate is what, 1ksps? I don't see any line hum, so that's good, but It's probably below the sensitivity of your scope or buried in all that other crap.

There is a reason you don't want to filter after you've digitized your signal. Before it goes in the 'scope, it's an analog signal so it has all frequencies, from 0 to infinity. When you digitize that signal, every one of those contributions to the signal gets stuffed into that data point. But because your sampling rate is less than infinite, you can't distinguish between signal and noise at a higher frequency. You won't be able to get rid of any noise that's at a higher frequency than half your sampling rate. And even eliminating anything close to that frequency is difficult.

As a rule of thumb, when it comes to noise the earlier you can nip it the better. And with a properly built filter, you won't be losing any information. The other thing you could try is hooking your sensor up in differential configuration instead of single-ended (just an assumption on my part that it's not already).

If I'm guessing right at what a "differentiation filter" is, I don't think you'll have much luck because the "slope" for the noise is probably less than some of the signal itself, and greater than any details you're trying to get out of the noise. All said and done it is a pretty strong signal.

What sensor are you using (model # & MFR) - I might poke around the spec sheets to see what's up.


great info, ill see what i can do. thanks!
The ultimate truth in paintball is that the interaction between the gun and the player is far and away the largest factor in accuracy, consistency, and reliability.

And yes, Gordon is the sexiest manifestation of "to the front."


#57 Egomaniacal

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Posted 05 July 2011 - 05:03 PM

If your scope has an FFT function I'd love to see an output with just the sensor plugged in and not moving.
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#58 cockerpunk

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Posted 05 July 2011 - 05:48 PM

If your scope has an FFT function I'd love to see an output with just the sensor plugged in and not moving.


easy to do an FFT after the fact too, ill look into that as well. been busy at work ...
The ultimate truth in paintball is that the interaction between the gun and the player is far and away the largest factor in accuracy, consistency, and reliability.

And yes, Gordon is the sexiest manifestation of "to the front."


#59 brycelarson

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Posted 05 July 2011 - 05:53 PM

If your scope has an FFT function I'd love to see an output with just the sensor plugged in and not moving.


we took some readings locked down before the testing for Gordo to start looking at the baseline.

you can download the software, take a look and tell me what you want me to record.

http://www.linkinstr...s.com/mso19.htm

it does have an FFT setting.

#60 Egomaniacal

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Posted 05 July 2011 - 06:27 PM

Am I completely misreading this in that you have a much higher bandwidth than you're using? Are you limiting the sample rate to make it manageable in excel?

I would think a screengrab of an FFT over say, 2.5kHz should be plenty. Just for shits and giggles you could do something bigger, too. It's running in demo mode for me since I don't have hardware so I can't quite see what the trigger/averaging is doing, but you could average it over some number of samples you think is sufficient to see any noise sources.

You've probably already realized that if you ran it at a higher sampling rate (I would think 10 ksps would be sufficient) you could probably do your filtering after you digitize your signal.

I don't suppose you have access to MatLab Posted Image
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#61 cockerpunk

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Posted 05 July 2011 - 06:48 PM

yeah, the output will only output 1000 data points, so 10 ksps would be like a millisecond.
The ultimate truth in paintball is that the interaction between the gun and the player is far and away the largest factor in accuracy, consistency, and reliability.

And yes, Gordon is the sexiest manifestation of "to the front."


#62 brycelarson

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Posted 05 July 2011 - 09:34 PM

yeah, it's hard to see without running with hardware - but watch the video. The way the free software works is that the screen is always 1000 samples wide. Basically you hit "go" and the software looks like it's doing nothing - once it's collected 1000 samples - which, in our case takes a second - it then displays the full 1000 samples. So we hit go, shoot then when the shot pops up on the screen we stop the software. At that point you save the 1000 data points as a csv and you start doing math.

#63 Egomaniacal

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Posted 05 July 2011 - 11:45 PM

That's a bummer. Impressive piece of hardware, completely ruined by software limitations.
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#64 brycelarson

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Posted 06 July 2011 - 05:28 AM

That's a bummer. Impressive piece of hardware, completely ruined by software limitations.


not really - it can talk to any software. If there are other, better, cheap or free options, let us know. And the info we get from this isn't worthless.

#65 Kermit

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Posted 06 July 2011 - 08:36 AM

I thought kick talk was a big no-no......

#66 Egomaniacal

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Posted 24 July 2011 - 02:58 AM

Any updates on the project?
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#67 brycelarson

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Posted 24 July 2011 - 10:06 AM

Any updates on the project?


not yet - I just did a stupid busy couple of weeks at work. soon.

#68 Jaccen

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Posted 24 July 2011 - 06:28 PM

Open source Matlab alternatives:

http://www.morlok.ne...b-alternatives/


Scilab tutorials:
http://www.scilab.or...ation/tutorials
http://wiki.scilab.org/Tutorials
http://www.scilab.or...tion&fileID=871

I used it for simplistic equations and it seemed to suffice. Though, I still fall back to Excel more often than not.

#69 Snipez4664

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Posted 24 July 2011 - 10:23 PM

The issue isn't really data processing as much as data acquisition, if I'm not mistaken. Once the data is available to the public, there will be plenty of people ready to torture it.
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#70 cockerpunk

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Posted 25 July 2011 - 09:05 AM

are you guys saying you want the raw data? that can be arranged pretty easily.
The ultimate truth in paintball is that the interaction between the gun and the player is far and away the largest factor in accuracy, consistency, and reliability.

And yes, Gordon is the sexiest manifestation of "to the front."


#71 Snipez4664

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Posted 25 July 2011 - 11:58 AM

The data without beign processed via the o-scope would probably be preferable, but I don't see why you couldn't crowdsource some fo the data processing and see what people come up with - let the cream rise to the top.
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#72 cockerpunk

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Posted 10 August 2011 - 09:12 AM

on august 2nd we redid the testing proceedure with the protege, mounting the sensor, the whole works to see how repeatable the whole system is -

Posted Image

peaks at 5ish, lows are at -5ish .... looks pretty damn consistent to me.
The ultimate truth in paintball is that the interaction between the gun and the player is far and away the largest factor in accuracy, consistency, and reliability.

And yes, Gordon is the sexiest manifestation of "to the front."


#73 CrazyLittle

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Posted 11 August 2011 - 11:59 AM

Ugh. You guys should have called me if you wanted to borrow a spoolie.

maybe im just a cocker freak, but i find the karni one the most interesting. notice how the second half of the cycle doesn't sync up very well, while the first half did ...


For a cocker freak, the answer should be obvious to you. Either the hammer is bouncing, or you're capturing the breech sensor waiting for the next paintball to load.

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#74 cockerpunk

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Posted 11 August 2011 - 12:08 PM

Ugh. You guys should have called me if you wanted to borrow a spoolie.


maybe im just a cocker freak, but i find the karni one the most interesting. notice how the second half of the cycle doesn't sync up very well, while the first half did ...


For a cocker freak, the answer should be obvious to you. Either the hammer is bouncing, or you're capturing the breech sensor waiting for the next paintball to load.


bingo
The ultimate truth in paintball is that the interaction between the gun and the player is far and away the largest factor in accuracy, consistency, and reliability.

And yes, Gordon is the sexiest manifestation of "to the front."


#75 tubberthump

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Posted 11 August 2011 - 12:32 PM

once winter rolls around i will send you my g4 just to see how bad it is

#76 cockerpunk

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Posted 11 August 2011 - 02:03 PM

so the componets of kick thread got me thinking, i think its time to dig out that punkworks dictionary and defines some terms. i think fundamentally we have two things -

1. the motion of the gun
2. the perception of motion the shooter feels

i propose we call the motion of the gun (total) as something, we call each componet of the motion X or Y. then we have an overal term for the perception the shooter gets from it.
The ultimate truth in paintball is that the interaction between the gun and the player is far and away the largest factor in accuracy, consistency, and reliability.

And yes, Gordon is the sexiest manifestation of "to the front."


#77 CrazyLittle

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Posted 11 August 2011 - 02:13 PM

Perhaps you might be able to quantify "smoothness" as the area deviation from the axis - such that a sharp but brief force would still have roughly the same area as a longer, slower but lighter force. Inertia would be (a) dampening force that counteracts this motion.

Think you could do a "heavy/light" comparison? Take a marker, kit it with very light components (13ci tank, 10-rnd tube, CF barrel) and then see how it compares to the same marker with 68/4500, steel barrel, full pinokio/240-rnd prophecy?

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#78 cockerpunk

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Posted 11 August 2011 - 02:14 PM

Perhaps you might be able to quantify "smoothness" as the area deviation from the axis - such that a sharp but brief force would still have roughly the same area as a longer, slower but lighter force. Inertia would be (a) dampening force that counteracts this motion.


i think the shooters percetion of those differences though are important.
The ultimate truth in paintball is that the interaction between the gun and the player is far and away the largest factor in accuracy, consistency, and reliability.

And yes, Gordon is the sexiest manifestation of "to the front."


#79 CrazyLittle

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Posted 11 August 2011 - 02:21 PM

But how do you quantify perception in an objective, measurable means?

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#80 cockerpunk

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Posted 11 August 2011 - 02:33 PM

But how do you quantify perception in an objective, measurable means?


well, you don't really. perseption is by defintion not objective.

my point is merely that the perception of a longer, lower accelleration, despite possibly moving the gun more, could be popularly interpretted as "smooth" despite mathmatically and objectivly not being the one with the smallest displacment.
The ultimate truth in paintball is that the interaction between the gun and the player is far and away the largest factor in accuracy, consistency, and reliability.

And yes, Gordon is the sexiest manifestation of "to the front."


#81 CrazyLittle

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Posted 11 August 2011 - 02:49 PM

Yeah, so you might as well objectively measure and quantify what you can, and then keep subjectivity separate while also noted.

In the end the most useful information is going to be the comparison between standardized test results. That's why Mike efficiency tests don't explicitly test peak efficiency but do give a good baseline of comparison across other test results.

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#82 brycelarson

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Posted 11 August 2011 - 03:49 PM

Yeah, so you might as well objectively measure and quantify what you can, and then keep subjectivity separate while also noted.


exactly. My thoughts on this are that we run two parallel tests using the same data.

I want to collect a library of guns for reference as well as just cause it'll be cool to have. While we're doing that my thought was that we record perception of the quality of the kick of the gun along side the graphs. That way we can later group guns that were perceived to shoot smoothly and see if we can determine what aspect of the guns' movement gave that impression.

The basic test that I proposed to Gordo last time we talked was to round up a big pile o guns at the field. We just set up in the chrono station and get a line of shooters. We have say 5 shooters and 10 guns. Each shooter shoots each gun and rates it on a smoothness scale - say 1 being least smooth and 10 being most kicky. We record graphs like those above for each gun. We can then take the mean perceived rating and see if there are any patterns. As long as we're consistent with how we post the test we should be able to continue to add data any time we feel like setting up at the field.

#83 Spitlebug

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Posted 11 August 2011 - 05:48 PM

I think in the end, this will be of little consequence to how I actually use or shop for markers. It is good science, but not what I would call practical.

So tempted to suspend Kitty just so I can say I have....
Okay, fuck it....I just banned Kitty, that's going in the sig.

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#84 brycelarson

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Posted 11 August 2011 - 06:03 PM

I think in the end, this will be of little consequence to how I actually use or shop for markers. It is good science, but not what I would call practical.


sure - that's fair. I'm in the same boat. I could really not give two shits about how much a gun kicks - BUT, it's obvious from the number of topics about kick on this forum that it matters to some people. I think a more practical application is for testing aftermarket parts. There are plenty that claim to reduce kick - we can now check them.

#85 Spitlebug

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Posted 11 August 2011 - 06:11 PM

Yes, I appreciate honesty in advertising.

How would you do that? Baseline with stock equipment, install aftermarket part and re-test?

So tempted to suspend Kitty just so I can say I have....
Okay, fuck it....I just banned Kitty, that's going in the sig.

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#86 brycelarson

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Posted 11 August 2011 - 06:32 PM

Yes, I appreciate honesty in advertising.

How would you do that? Baseline with stock equipment, install aftermarket part and re-test?


sounds about right to me.

#87 Phenomx

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Posted 12 August 2011 - 10:26 AM

I get no to minor kick when using invert mini stock barrel until i install a freak with a very small bore, kick increased by a lot

#88 Troy

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Posted 12 August 2011 - 11:54 AM

I get no to minor kick when using invert mini stock barrel until i install a freak with a very small bore, kick increased by a lot


I'm VERY interested to know how much kick increases with various bores when the marker is chronoed at a similar speed (like 280 fps)...
\m/

#89 rntlee

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Posted 13 August 2011 - 05:26 PM

... I could really not give two shits about how much a gun kicks - BUT, it's obvious from the number of topics about kick on this forum that it matters to some people. I think a more practical application is for testing aftermarket parts. There are plenty that claim to reduce kick - we can now check them.


Any chance you guys could check out whether or not lighter hammers reduce kick in Tippmanns? I bought a Dark Horizon Titanium bolt for mine a few years back, but didn't think there's was much difference in kick. I think the increased cycle speed of the lighter bolt offsets any gains from the reduction in mass.

Edited by rntlee, 13 August 2011 - 05:27 PM.


#90 brycelarson

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Posted 13 August 2011 - 06:58 PM


... I could really not give two shits about how much a gun kicks - BUT, it's obvious from the number of topics about kick on this forum that it matters to some people. I think a more practical application is for testing aftermarket parts. There are plenty that claim to reduce kick - we can now check them.


Any chance you guys could check out whether or not lighter hammers reduce kick in Tippmanns? I bought a Dark Horizon Titanium bolt for mine a few years back, but didn't think there's was much difference in kick. I think the increased cycle speed of the lighter bolt offsets any gains from the reduction in mass.


I've got a borrowed 98 here - but no A5 to test parts in.

#91 rntlee

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Posted 14 August 2011 - 11:54 AM

If you've got a 98, my Dark Horizon titanium hammer will fit it (60% the weight of the stock hammer)...but it's no longer sold and it's not quite as light as the Techt hammers being sold today. If you'd like to try it, I can send it down to you.

#92 cockerpunk

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Posted 14 August 2011 - 03:33 PM

i'd love to try it out.
The ultimate truth in paintball is that the interaction between the gun and the player is far and away the largest factor in accuracy, consistency, and reliability.

And yes, Gordon is the sexiest manifestation of "to the front."


#93 Lotus

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Posted 14 August 2011 - 04:35 PM

I really wish you guys had this rig suspended in mid-air or something. The point of an accelerometer is to measure acceleration, which is the result of the net force on an object. With Cockerpunk holding the marker, he's applying additional forces on the marker and therefore skewing the data that we really want, which is the acceleration caused solely by the marker cycling/firing. If it were to be suspended, I believe it would yield better results. Granted using accelerometers this way, we would have to measure the mass of the entire setup and multiply the resultant acceleration by the mass to yield the true numbers we wanted, but I think that's a relatively easy step.

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#94 Snipez4664

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Posted 14 August 2011 - 05:15 PM

we already have repeatable data that approximates game conditions - the physical setup of the rig really can't be much better, and we're already past it
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#95 rntlee

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Posted 14 August 2011 - 09:16 PM

i'd love to try it out.



Ok, shoot me an address and I'll drop it in the mail, bro.



#96 brycelarson

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Posted 15 August 2011 - 07:39 AM

I really wish you guys had this rig suspended in mid-air or something. The point of an accelerometer is to measure acceleration, which is the result of the net force on an object. With Cockerpunk holding the marker, he's applying additional forces on the marker and therefore skewing the data that we really want, which is the acceleration caused solely by the marker cycling/firing. If it were to be suspended, I believe it would yield better results. Granted using accelerometers this way, we would have to measure the mass of the entire setup and multiply the resultant acceleration by the mass to yield the true numbers we wanted, but I think that's a relatively easy step.


As snipez said - at this point we're happy with the rig. By taking multiple samples with multiple applications of the rig and showing that they produce nearly identical results we've shown that the shooter isn't introducing problems.

Lee - PM inbound. you can send the stuff to me - I've got the gun and the test rig at my place.

Edited by brycelarson, 15 August 2011 - 07:43 AM.


#97 Spitlebug

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Posted 15 August 2011 - 11:41 AM


I get no to minor kick when using invert mini stock barrel until i install a freak with a very small bore, kick increased by a lot


I'm VERY interested to know how much kick increases with various bores when the marker is chronoed at a similar speed (like 280 fps)...


Stands to reason if you get a large FPS jump going from overbore to underbore that the kick would be greater. Perhaps on order of a few joules.

So tempted to suspend Kitty just so I can say I have....
Okay, fuck it....I just banned Kitty, that's going in the sig.

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#98 Snipez4664

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Posted 15 August 2011 - 02:30 PM

Not with normalized velocity - the internals should be able to shift more softly to produce the same fps with an underbore
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#99 Spitlebug

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Posted 15 August 2011 - 03:30 PM

Define "normalized velocity".

If by normalized you mean under bore shooting @ 300 FPS and overbore shooting @ 300 FPS, then your example passes muster.

So tempted to suspend Kitty just so I can say I have....
Okay, fuck it....I just banned Kitty, that's going in the sig.

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#100 Troy

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Posted 15 August 2011 - 03:30 PM

Not with normalized velocity - the internals should be able to shift more softly to produce the same fps with an underbore


I was thinking less about the internal movement, and more about the gas exhaust (and probably along the lines of what Spittle is thinking). If speed is normalized, then the underbore should kick more despite the fact that you are ultimately using less gas (and therefore less energy) because the pressure released from the barrel will be more discrete than that of an overbore situation.

It definitely could be true that internals can shift more softly and it may even mask the barrel exhaust effect I described above.

If we shot both a spoolie and put it up against a Tippmann, for example, (which has a HUGE hammer) we could possibly see opposite results between under and overbores.

EDIT: I rethought this out, and it's probably less about gas exhaust and more about acceleration... therefore, the under bore could kick more, because the ball is accelerated faster... not because the gas released will be more discrete.

Edited by Troy, 15 August 2011 - 03:33 PM.

\m/




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