[Jack Wood]

brycelarson, on Feb 17 2009, 05:42 PM, said:

elves, well, elves or gnomes...

You see, there you go again.....................you forgot the damned fairies and pixies!!!

Coem on, if you're going to do it, do it right

I hear you guys and I'm just trying to play the devils advocate. A role you are both very familiar with

For me the Alien video was quite compelling viewing. I'm not saying it's backspin or gyroscopic effect, but there definitely seems to be something different there.

As Gordon says, if you do the vids and you can't see the spin, what then? First you have to prove without doubt that there is a difference in trajectory between the systems. Maybe a very boring 20', 40', 60' etc etc tests with both systems with enough shots to give you a nive mean flightpath for both. then work back from there.

And maybe a modified one of these

http://www.edhsport....lf/software.php

Manufactured in South Africa by a specialist ballistics tracking company.........I really really want

[cockerpunk]

or jack, how about a nice composite image built from a nice 600fps shot of the whole flight path?

[Jack Wood]

cockerpunk, on Feb 17 2009, 06:08 PM, said:

or jack, how about a nice composite image built from a nice 600fps shot of the whole flight path?

I'd be amazed if you can capture that

Have a look at that software. It gives lift and drag coificients, side and backspin rates, 3D trajectory. And the thing about this is that it is based on actual data, not interpolated results from initial conditions.

[cockerpunk]

there perspective might be hard to to get in frame, but it wouldn't be hard to make an image, then put some lines on it.

[uranub132]

has any1 tried to use these in a normal hopper?

[Spitlebug]

cockerpunk, on Feb 17 2009, 09:27 AM, said:

the big question, and one me and jack hae talked about, is if we see no backspin, and yet we still have an elevated Y impact. what then?

This means the assumptions we are putting on paintball flight characteristics and trajectory are inherently wrong.

Jack Wood, on Feb 17 2009, 10:04 AM, said:

For me the Alien video was quite compelling viewing. I'm not saying it's backspin or gyroscopic effect, but there definitely seems to be something different there.

Link to said Alien video?

This post has been edited by Spitlebug: 17 February 2009 - 01:37 PM

[A.E.D.paintballer]

very interesting stuff!(claps)

i think that when the paintball is in the barrel, and that air is pushing on the back of the paintball it should spin the opposite way of when it is in mid air: / = the fin's direction ok? when paintball is shot air pressure is pushing in this direction >/ causing clockwise rotation. when ball is in flight pressure is applied on front of ball /< causing counter-clockwise rotation. my guess is combining this ball with a rifled barrel would accually give more rotation(not really shure if that adds flight stability tho).

are these out yet? regardless, i will be modding my trracer to load these and fire them, just to piss off people who say paintball snipers dont exist

[Troy]

Good show Jack, if I had been paying attention more closely I would have made that point myself. Devil's advocate can be a crappy job, but its a necessary evil sometimes.

[Scooby]

Lord Odin, on Feb 14 2009, 10:52 PM, said:

Since they travel faster at longer distances, I would think it safe to say that they have a flatter trajectory and don't drop as quickly. Did you notice that?

They would still drop at the same rate, as gravity will affect them as much as anything else, ie if fired at the same angle to the ground this should hit the ground at the same instant as a paintball, however as the balls velocity is reduced more slowly it would land further than the regular paintball. The trajectory would have the same profile but stretch over a longer distance, but a hight vs time graph should be identical.

[Lord Odin]

Scooby, on Feb 18 2009, 07:22 AM, said:

Lord Odin, on Feb 14 2009, 10:52 PM, said:

Since they travel faster at longer distances, I would think it safe to say that they have a flatter trajectory and don't drop as quickly. Did you notice that?

They would still drop at the same rate, as gravity will affect them as much as anything else, ie if fired at the same angle to the ground this should hit the ground at the same instant as a paintball, however as the balls velocity is reduced more slowly it would land further than the regular paintball. The trajectory would have the same profile but stretch over a longer distance, but a hight vs time graph should be identical.

Yes, they drop at the same rate but when shot at the same target at equal angles, their heights will be different. If one is traveling faster than the other, it takes less time to reach its target. That means it's height that it falls due to gravity is less since its a product of time. On the target, that means the one traveling faster will arch less and will hit the target higher up than the slower traveling one. Now if you change the angles so that they hit at the same spot on the target, the slower one will have to have a higher angle and will have a larger arch than the faster projectile. That means a faster moving projectile will have a flatter trajectory. If you take it to the extreme and reduce time to almost 0, it would create a straight line.

[Spitlebug]

^^ Ding ding ding! We have a winner!

The real question though is why do these have what may be considered a more consistent trajectory? We do know that it pretty much has everything to do with the fin at the back and probably the orientation therein. Also if the projectiles fly faster, but still have the same exit velocity what is allowing them to mitigate that loss in speed? Does the angled portions of the fin reduce the overall displacement of atmosphere by creating a spin?

I imagine this as looking at a standard paintball being a nerf football and a Tiberius round being a nerf football with rear fins. I wouldn't say either fly faster, but one can be sure that the nerf football with fins flies in a much more desired tracjectory.

So, I guess in summary we need to ask these questions:

- Does the Tiberius projectile maintain speed better than a standard paintball (mass, shape etc...)?
- Do the angled sections of the fin induce a spin (would spin even account for this)?
- Does the fin align the projectile in flight or is it due to the loading of the round and the initial acceleration through the barrel?

We need to get a rep from Tiberius Arms in here to answer a few basic questions. For example I am sure they can get us a volume weight for the rounds. They could be heavy as hell. Shooting them may not even be all that efficient.

I imagine having them get a weight of 1000 count or 2000 count and then subtracting the tare of the containing vessel would give us a good mean weight.

This post has been edited by Spitlebug: 18 February 2009 - 12:30 PM

[Leafy]

Spitlebug, on Feb 18 2009, 12:26 PM, said:

^^ Ding ding ding! We have a winner!

The real question though is why do these have what may be considered a more consistent trajectory? We do know that it pretty much has everything to do with the fin at the back and probably the orientation therein. Also if the projectiles fly faster, but still have the same exit velocity what is allowing them to mitigate that loss in speed? Does the angled portions of the fin reduce the overall displacement of atmosphere by creating a spin?

I imagine this as looking at a standard paintball being a nerf football and a Tiberius round being a nerf football with rear fins. I wouldn't say either fly faster, but one can be sure that the nerf football with fins flies in a much more desired tracjectory.

So, I guess in summary we need to ask these questions:

- Does the Tiberius projectile maintain speed better than a standard paintball (mass, shape etc...)?
- Do the angled sections of the fin induce a spin (would spin even account for this)?
- Does the fin align the projectile in flight or is it due to the loading of the round and the initial acceleration through the barrel?

We need to get a rep from Tiberius Arms in here to answer a few basic questions. For example I am sure they can get us a volume weight for the rounds. They could be heavy as hell. Shooting them may not even be all that efficient.

I imagine having them get a weight of 1000 count or 2000 count and then subtracting the tare of the containing vessel would give us a good mean weight.

the shape of the tib rounds is much more aerodynamic than just a ball (they're be even better if they didnt have the hole in the back since thats causing a larger low pressure zone behind it), the spinning should also make them lose less velocity since isnt that a theory with rifling on real gun.

[brycelarson]

Spitlebug, on Feb 18 2009, 11:26 AM, said:

So, I guess in summary we need to ask these questions:

- Does the Tiberius projectile maintain speed better than a standard paintball (mass, shape etc...)?
- Do the angled sections of the fin induce a spin (would spin even account for this)?
- Does the fin align the projectile in flight or is it due to the loading of the round and the initial acceleration through the barrel?

We need to get a rep from Tiberius Arms in here to answer a few basic questions. For example I am sure they can get us a volume weight for the rounds. They could be heavy as hell. Shooting them may not even be all that efficient.

I can answer a couple of these.

1. I think so - I need to get the footage of the standard paintballs but time from firing to impact seemed shorter. I'll get some video of regular paint in the next couple days - then check the audio track to see shot to impact time on both.

Jack Wood weighed a few - they were between 3.0 and 3.1 grams. the ATSM on paintballs says that they have to weigh less than 3.5g I think. Mann got weights from (off the top of my head) 2.4 and 3.2g for different paints - so they're right on for weight. Volume - don't know for sure - but there are a couple of things I noticed. There certainly isn't much fill in these guys. I think that the front end looks to be about 1/2 of a paintball. This makes sense since there is a pretty good chunk of platic in the fins. Also, if you see in my video - they're very nose heavy. They sit like weeble-wobbles on the table. This would indicate to me that the semi-shpere and the tail fins weight similar amounts and the fill adds to the nose weight.

I don't know if the alignment happens in the barrel - but the two factors - the fins and the center of gravity being forward would both be good reasons to think that the alignment is mostly during flight. At the end of my vid you can see the skirts stuck to my target - they hit very squarely to the baord. From that it looks as if the alignment is really good - not much wobble in them.

[brycelarson]

I just shot some DXS silver in the backyard to compare the video with the first strike rounds.

I stuck the vid in my editing software and compared the audio tracks.

here are the results for the time to target for the different rounds:

tib
3:55.93 --> 3:56.27 = .34 seconds flight time = aprox 220 fps
4:49.80 --> 4:50.20 = .40 seconds flight time = aprox 187.5 fps
5:01.13 --> 5:01.53 = .40


DXS silver
5:26.13 --> 5:26.53 = .40
5:29.67 --> 5:30.07 = .40
5:35.27 --> 5:35.67 = .40

all shots were similar fps at the muzzle, the times are notations of the shot fired and impact on the sound track. All shots fired from .685 12" CP barrel - temperature was aprox 30 degrees. All shots fired at 75 feet - I used the time to target to derive an aprox fps mean through the entire flight time of the projectile.

the sample size is pretty small - but it appears that the tib rounds have no benefit on the deceleration front at 75 feet.

edit - here's an update. I realized I should account for the speed of sound on the second sound signature. Since the target was 75 feet away - and the speed of sound at 30 degrees is 1085 fps give or take a bit. So, the actual time to impact should be reduced by .07 seconds. This accounts for the sound arriving at the camera .07 seconds after the actual impact. - this reduces the time in flight to .33 seconds for 75 feet - which makes the mean speed 227 fps - which sounds better to me.

This post has been edited by brycelarson: 24 February 2009 - 04:14 PM

[sockfoot]

Interesting Data!

First, the normal paintball test had something that I had speculated about some time ago. This being that the kick of the paintball being shot would cause the slight rise in the barrel and try to put a tiny amount of top spin on the paintball. My guess based on the data (all the shots in the 270fps range) is that the jolt caused the mid range shots to dive. The clamp rebounded the shot, negating this effect on the slower shots and was too slow to cause this effect on the faster shots, because they left the barrel too soon. There is no telling if this effect would be this consistent when shot from the hand.

Regardless, it has no effect on a riffled FS round because they can not take backspin. As such the FS round should have an up and down displacement directly relating to the velocity. Which leads me to conclude that there are two outliers in the test data. These are the two farthest shots to the left. Also, I would like to point out that the shot pattern is a diagonal. Plot the shots and you will see that they are in a row extending from the lower left to the upper right. Why are they lined up on an angle like this? Because, as the FS round begins to drop, Gyroscopic stability and inertia try to keep the round pointed parallel to the barrel. The downward movement has a spin that will deflect the shot to one side. It should be less than a perfectly riffled shot of a regular paintball because a regular paintball will not be tipped by the air it passes through and forced to maintain spin perpendicular to the motion.

Therefore (I know it would cost a lot more money) the accuracy of a FS round should be compared to rounds that were measured at the same velocity. Then you count how many shots deviated from the center. Either that or you have to come up with some sort of conversion formula and work some majic with the statistics.

As such, we need someone to determine the most consistent paintball marker made because that would be the marker to modify so that it would handle FS rounds.

Attached File(s)

•  FSAccuracyPlot.JPG (31.16K)
  Number of downloads: 1
•  PBAccuracyPlot.JPG (45.63K)
  Number of downloads: 1

[brycelarson]

yeah, the diagonal pattern of the first strike rounds was interesting to me as well. I did notice it when I shot them.

However, no large scale inferences should be made on sample sizes this small. 8 shots isn't enough to start to predict what a large-scale test pattern would look like. During our accuracy test we had a number of data sets that started to look like something - but by the time they were complete (20 samples or more) they had turned into exactly the same thing as all the rest. I would hesitate to make any claims about the first strike pattern until you can shoot 20 or 30 in a group.

As to the velocity question - we did track impact location to velocity in our accuracy test - there was no correlation. We had patterns +/- 1" in standard deviation at 50' with velocity standard deviations fluctuating from 4 up to 8. I use the idea that 2 x Standard deviation is the equivalent of +/- fps - so that means that a gun shooting +/- 8 and a gun shooting +/- 16 are equally accurate at 50 feet.

accuracy test

As to the most consistent gun - CockerPunk's emag will do +/- 3 fps with an extreme underbore on a large sample size test.

[Jack Wood]

So one shot FS round took 0.34s and the other two took 0.40s? That is a large discrepency, wouldn't you say?

So what are we all learning so far from all the Punkworks tests and data sets to date? That maybe 75' is too short to show anything of of any significance? Even when comparing apples to oranges, let alone satsumas to clementines?

This post has been edited by Jack Wood: 26 February 2009 - 07:15 AM

[brycelarson]

yup, that's why we're doing 125' in a few weeks

Don't worry Jack - we can learn.

I do want to point out though - that speedball engagement distances are often moderate to short. It's not unusual to be shooting at a target at 50'. So, while the tests may not be elucidating information applicable to all situations - it certainly does apply to some.

and yes, a 10% + variation was much more than I expected to see - especially since the chrono readings were very similar and the impact location was very close. You can't see it on the video - but the first 4 shots were in a group about 4" across with the 1st and 4th shot actually on top of each other. So, the one measured fastest didn't impact in a different location.

This post has been edited by brycelarson: 26 February 2009 - 09:37 AM

[Jack Wood]

And your confident with those readings? It just doesn't seem to make sense that the variation between shots would be that large. I'm not saying your not right, but it just doesn't add up. I think you need to do a couple more rounds on that. Certainly doesn't make sence that a) 2 out of 3 FS rounds recorded the same time to target as the paintballs, and that the paintballs were so consistent and the FS rounds were far from.

[brycelarson]

well, I can dig into the video files I was using - but with the resolution I was able to get on the editing software I think it's pretty good.

I'll try dumping the files into something else and checking again.

Like I said - I was surprised at the same thing - my gut feeling it that it's measuring or recording error on my part - but I don't ave enough data to throw it out.

Next time we shoot them I'll get a bunch of samples. ANd at 125' any differences should be very visible (audible)