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Old 06-13-2014, 11:15 PM #85
Graebner
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Could be a mixture of all... The eye pipe being lil tight, paint breaking along seam, and the nt's bolt pushing air thru a very small hole pin pointing the airflow... Have u tryes over bore vs underbore vs proper bore? Another thought
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Old 06-15-2014, 06:05 PM #86
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Well come to think of it Dye did actually change some things that might affect the bolt movement.

1. Eyepipe. Dye released a changed eyepipe with changed diameters. The drag of the bolt tip oring could slow down the bolts accelleration when it hits the transition point.
2. Dye released a small orange bumper o-ring to not create exessive drag on the bolt (which would slow down the bolts acceleration at transition point)
3. People talk about changing bolt tip o-ring to smaller to shoot more fragile paint (smaller bolt tip o-ring would create less drag on bolt which would not slow down the bolt so much in the transition point)
4. NT11 has smaller bolt sail o-ring. (this would be a smaller diameter and surface area, which come in contact whith can at the transition point thus creating less drag)
5. Increase pressure to 130-140 psi, using spacer body and/or blue bolt insert. (Higher pressure would increase the force on the bolt which will make it easier to force the oring to compress and enter the can)

Not sure if all these work as intended but it might explain som things.
I would realy like to make a new can with a much smoother transition (chamfer where the bolt sail o-ring enters on to the can surface).
A hevier bolt would be less reactive to changes in acceleration an would also be one possible way to test this theory.

The first thoug will bee changing the bolt sail o-ring, and bolt tip to something with less drag. Maybee an X-ring.

When all parts for my test rigg is reddy this will also be evaluated.

Last edited by rosakatten : 06-16-2014 at 11:54 AM.
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Old 06-18-2014, 02:11 PM #87
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Today I got a shipment of acrylic pipe. This will be the see through barrel and vill be fited to the aluminium body I am making.
When all is done I will be able to film with highspeed camera how the bolt moves and verify speeds or hasitations that may affect paint breakage.
https://www.dropbox.com/s/d2rh68s3cu...ylr%C3%B6r.jpg
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Old 06-18-2014, 02:25 PM #88
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Really cool. Throw this out there.....is there a way you can add color or smoke into your air. Which may be possible before or after the regulator on the gun. To also show air flow. Not only that being cool. But possible open up ideas on air flow. It will probably all happen too fast in cycle speed to see. But in a video it may work.
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Old 06-18-2014, 02:59 PM #89
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I guess it is possible to add some coloured water in the valve part of the bolt.
Thanks for the tip. I think I will give it a try just for the fun of it.
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Really cool. Throw this out there.....is there a way you can add color or smoke into your air. Which may be possible before or after the regulator on the gun. To also show air flow. Not only that being cool. But possible open up ideas on air flow. It will probably all happen too fast in cycle speed to see. But in a video it may work.
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Old 06-23-2014, 09:52 PM #90
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what about changing the internal surface area of the bolt that pushes the bolt forward? or change the angle of the inside of the bolt at the shoulder to maybe slow the bolt down?
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Old 06-24-2014, 08:28 AM #91
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I think the first step should be to change bolt sail o-ring from 15 to 14 or 13 (on NT11) to see if there realy is a bigg difference to paint breakage. (this should make it easier for the oring to enter the can).
I have only dryfired my NT11 with size 13 on bolt sail and it does'nt leak.
I also have a size 13 on bolt tip to test since the bolt tip o-ring creates drag in the eyepipe if it is too big.
Also softer o-rings could be a good idea. And a better chamfer for the o-ring to enter the inner diameter of the can should be good.
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what about changing the internal surface area of the bolt that pushes the bolt forward? or change the angle of the inside of the bolt at the shoulder to maybe slow the bolt down?
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Old 06-24-2014, 11:42 AM #92
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Saw this in another thread awhile back, but did you ever think about the bolt bouncing forward on the retraction? If you get a high speed camera you may want to check for that as it will obliterate paint

Also did you consider reducing the plunger to bolt flow holes at all? This may allow the pressures to build up more slowly to cause the bolt's forward movement to start at a slower speed. From what I've read, a big problem with the NT bolt was the area controlling the forward stroke is quite large, so when the plunger quickly shifts the flow of air to that area there is a lot of force acting upon the bolt quickly
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Old 06-24-2014, 01:28 PM #93
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This is a clip I took with an old crapy highspeed camera and too little light. Made in january 2013. The grapite gun is NT11 and green is DM11 see the difference. The NT have a closed volume that will slow the bolt down on the backward stroke if all seals are ok. It is actualy better than the DM11.
https://fbcdn-video-a.akamaihd.net/hvideo-ak-xpa1/v/t43.1792-2/768608_10151205555506616_23339_n.mp4?oh=929c6ca92e 5aa4d1b26e494895c9624a&oe=53A9D0E2&__gda__=1403639 242_f9a70ff364a385ea2bf881c51ddc4ed4

Have you ever put your finger in the breach on the NT and fired? It is not harder on paint than a DM in the first part of the bolt stroke.

Tomorow I have called to a meeting to invest in a new camera. Phantom M310. This is a budget camera that will suit my needs at work and also my private investigations... When I get it I will be able to shoot 640x480 in 10 000 fps. This will help me verify bolt speeds and if there are any cycling issues and if changing certain o-rings will help.

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Originally Posted by d0cwh0 View Post
Saw this in another thread awhile back, but did you ever think about the bolt bouncing forward on the retraction? If you get a high speed camera you may want to check for that as it will obliterate paint

Also did you consider reducing the plunger to bolt flow holes at all? This may allow the pressures to build up more slowly to cause the bolt's forward movement to start at a slower speed. From what I've read, a big problem with the NT bolt was the area controlling the forward stroke is quite large, so when the plunger quickly shifts the flow of air to that area there is a lot of force acting upon the bolt quickly

Last edited by rosakatten : 06-24-2014 at 01:36 PM.
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Old 06-24-2014, 01:39 PM #94
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The video is 336x96 1200 fps filmed with Casio Exilim EX-F1 from 2008... crap but still sometimes useful.
The last part of the video is 1200fps slowed down to 1/5 so that is as slow as at 6000fps

Last edited by rosakatten : 06-24-2014 at 01:53 PM.
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Old 06-24-2014, 01:56 PM #95
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that's really cool...thanks for sharing

Would you mind sharing your measurements of the bolt? I would be interested to see how much force is acting upon the ball upon firing and comparing it to other markers

edit: never mind...I see why it's two stages now. However, it looks like there is more force on the bolt during the initial stroke than at the end of the stroke. Is this correct?
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Old 06-24-2014, 02:05 PM #96
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You and PH mention the finger in breech part. do you have the means to somehow measure the impact pressure? even though both operate at slightly differ pressures. the DM moves the bolt by the lpr, correct? then that allows the spooled greater pressure to speed the ball up.
the nt bolt moves from the spooled air.
and i know you know all this. i am learning as i speak this out.
the rear travel on the bolt is slowed from the plunger tip oring when the spooled air exhausts and the air around the can has the greater pressure.
what about a spring that is incredibly light compression...like an axe concept.
and removing the plastic orange middle oring on the bolt. this obviously would change the forward speed and increase the return speed slightly.

to me in the video you made and seeing the comparison of the dm and nt animation. its all in the forward movement of the bolt. using the same pressure to control the bolt but with differ volumes could be partial factor. my other feeling is the initial blast from the plunger to move the bolt.
i know you've mentioned it kinda like a solenoid itself. but if the parameters can be changed to soften/smoothen that initial movement. it might be the game changer.
but again im no mech engineer. lol and probably for good reason..
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Old 06-24-2014, 02:45 PM #97
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Yes there is more force on the first part of the stroke this also equals to "low speed" second part is lower force and higher speed.
I will try to meassure the force and compare to calculations.
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that's really cool...thanks for sharing

Would you mind sharing your measurements of the bolt? I would be interested to see how much force is acting upon the ball upon firing and comparing it to other markers

edit: never mind...I see why it's two stages now. However, it looks like there is more force on the bolt during the initial stroke than at the end of the stroke. Is this correct?
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Old 06-24-2014, 03:01 PM #98
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What I have learned from trial and error is that preassure is not the big deal of paint breaking issues of most guns. Take DM vs EGO both run LPRs at around 75 PSI. Both operate diferent and EGO have a faster moving bolt due to pressure on a small diameter ram (low force). DM bolt move slower on a bigger bolt sail diameter o-ring (greater force but slow).

I have not seen much of problems related to high pressure and small inner diameter bolts although I initialy thought that that might be an issue with the NT.
I can se a small difference n accuracy if I compare my 3 DM:s against my 3 NT:s and also EGO SL74 ans AXE. DM have big inner diameter which increases slowly untill the boltface. Nt and axe ang EGO SL74 have constant diameters which may somehow create a more linear airflow or by some mean not create as much spin on paintballs... Dont know but all my DM:s are pretty much spraycans. NT, AXE and the EGO is more acurate or feels like that anyway.
I might do a test some day.
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Originally Posted by the korean1 View Post
You and PH mention the finger in breech part. do you have the means to somehow measure the impact pressure? even though both operate at slightly differ pressures. the DM moves the bolt by the lpr, correct? then that allows the spooled greater pressure to speed the ball up.
the nt bolt moves from the spooled air.
and i know you know all this. i am learning as i speak this out.
the rear travel on the bolt is slowed from the plunger tip oring when the spooled air exhausts and the air around the can has the greater pressure.
what about a spring that is incredibly light compression...like an axe concept.
and removing the plastic orange middle oring on the bolt. this obviously would change the forward speed and increase the return speed slightly.

to me in the video you made and seeing the comparison of the dm and nt animation. its all in the forward movement of the bolt. using the same pressure to control the bolt but with differ volumes could be partial factor. my other feeling is the initial blast from the plunger to move the bolt.
i know you've mentioned it kinda like a solenoid itself. but if the parameters can be changed to soften/smoothen that initial movement. it might be the game changer.
but again im no mech engineer. lol and probably for good reason..
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Old 06-24-2014, 03:51 PM #99
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Quote:
Originally Posted by rosakatten View Post
Yes there is more force on the first part of the stroke this also equals to "low speed" second part is lower force and higher speed.
I will try to meassure the force and compare to calculations.
I'm a bit confused. Please correct me if I'm wrong. If you have a greater amount of force on the initial forward stroke of the bolt you will have a greater amount of acceleration than on the later part of the stroke. When the bolt reaches the second stage of its forward stroke its rate of acceleration slows down. This is opposite to how most two stage bolts work in paintball (axe, ego, etc.). There, the rate of acceleration increases as the bolt moves forward, not decreases. Perhaps the NT bolt is accelerating too quickly on it's initial forward stroke.

Also just thought of this, but if the change in acceleration is really sudden, perhaps the bolt is losing "contact" with the ball halfway into the firing cycle.
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Old 06-24-2014, 04:43 PM #100
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Force is pressure times area.

Think big bolt sail o-ring equals big area. Add length of stroke and you get volume. Big volume as in the first part of bolt stroke means that it fills slower than a smaller volume,so it moves slower on that big diameter than on a small diameter using the same pressure.

Big force is not the same as big speed.
Have you used a hudraulic jack to raise a car? it works on the principle of a small piston which you can move with the force of your foot on a lever. This small volume of oil enters a much larger cylinder which lifts the piston and car with high force. The big cylinder moves a tiny increment for each stroke of the small piston.

Air is about the same with the difference of using a compresseble transfer media.
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Originally Posted by d0cwh0 View Post
I'm a bit confused. Please correct me if I'm wrong. If you have a greater amount of force on the initial forward stroke of the bolt you will have a greater amount of acceleration than on the later part of the stroke. When the bolt reaches the second stage of its forward stroke its rate of acceleration slows down. This is opposite to how most two stage bolts work in paintball (axe, ego, etc.). There, the rate of acceleration increases as the bolt moves forward, not decreases. Perhaps the NT bolt is accelerating too quickly on it's initial forward stroke.

Also just thought of this, but if the change in acceleration is really sudden, perhaps the bolt is losing "contact" with the ball halfway into the firing cycle.

Last edited by rosakatten : 06-24-2014 at 04:45 PM.
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Old 06-24-2014, 04:48 PM #101
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I think you might have missed this part of this thread. This is what I belive is the problem with the NT. A change in speed is a risk of loosing contact with the ball and creating more impact on the ball.
The rig I am building now will be able to film the bolt movement and show if the bolt breaks the ball after leaving the breach-

You are correct on this one. If anyone would care to test changing the bolt sail o-ring from 15 to 13 on NT11 and check if this helps against paint breakage I would be very thankful. I will try this as well as said earlier.

Quote:
Also just thought of this, but if the change in acceleration is really sudden, perhaps the bolt is losing "contact" with the ball halfway into the firing cycle.

Last edited by rosakatten : 06-24-2014 at 04:52 PM.
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Old 06-24-2014, 06:28 PM #102
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Quote:
Originally Posted by rosakatten View Post
Force is pressure times area.

Think big bolt sail o-ring equals big area. Add length of stroke and you get volume. Big volume as in the first part of bolt stroke means that it fills slower than a smaller volume,so it moves slower on that big diameter than on a small diameter using the same pressure.

Big force is not the same as big speed.
Have you used a hudraulic jack to raise a car? it works on the principle of a small piston which you can move with the force of your foot on a lever. This small volume of oil enters a much larger cylinder which lifts the piston and car with high force. The big cylinder moves a tiny increment for each stroke of the small piston.

Air is about the same with the difference of using a compresseble transfer media.
In terms of volume, is this the section you are referring to? Don't you have to consider the flow rates from the plunger into this area as well. From my understanding of the NT, it shifts a large amount of flow into this area. Wouldn't that cause the pressures rates to increase quickly leading to a fast acceleration on the initial forward stroke?

If you do have to consider the flow rates, can't you choke the flow so the pressure build rate is slower? Would this avoid the bolt acceleration issues by having a more even bolt speed?

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Old 06-25-2014, 02:26 AM #103
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Yes the arrow points to the volume that I am referring to which will increase untill the red bolt sail o-ring hits the green can. The problem is that it does not mater very much what you do because when the o-ring enters the can it will require force to compress the oring and slow the bolt down momentarily.
This might cause the ball to roll away from the bolt and the be caught up when the bolt accellerates on the second stage.

The NT11 has a smaller bolt sail ( I gues to decrease the force needed to compress but it also has lower operatin pressure which can cause problems with entering the can due to lower force). Recomendations from some techs was to use spacer in body and bolt to increase operating pressure which can overcome the dificulty of compressing the bolt sail o-ring when entering the can.

I did a test today with size 13 oring on bolt sail. This requires less force to compress and thus does not slow down as much when entering the can.
I used a NT10 with NT11 bolt and drilled blue insert ID 9mm. Dont know dwell or pressure but I will check that later. (also used DM eyepipe)
I shot high quality paint that break from 70-80cm height. No problems whatsoever...

The 13 oring might not last as long since it is streched more but seem to work good.
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In terms of volume, is this the section you are referring to? Don't you have to consider the flow rates from the plunger into this area as well. From my understanding of the NT, it shifts a large amount of flow into this area. Wouldn't that cause the pressures rates to increase quickly leading to a fast acceleration on the initial forward stroke?

If you do have to consider the flow rates, can't you choke the flow so the pressure build rate is slower? Would this avoid the bolt acceleration issues by having a more even bolt speed?

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Old 06-25-2014, 03:30 AM #104
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Not sure if flow will make a big change in this, but the Billy Wing macroline on spool might help a little bit. This mod semed to work diferent on diferent guns back in 2010 but it might be worth trying.

I would rather sugest trying softer o-rings or smaller orings on bolt sail and bolt tip.
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Old 06-25-2014, 01:57 PM #105
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Tested today. NT10 Nexus with NT11 bolt using 13 size oring in bolt tip and bolt sail. DM eyepipe but the eyes are removed to be replaced so ramping is not possible. I know that shooting one ball at a time without loader my NT11 will still break balls in the barrel so this test without ramping still proves that it does not break balls.
I will post some other video with chrono, and PSI settings and also using my NT11 with original bolt and with changed orings to show if it helps. I dont know for sure until I try changing orings on my NT11 bolt first with original orings and breaking balls and then chang to se if the problem is solved.

I did this test alone with my phone so i could not realy show droptest and all in the same clip.
https://www.youtube.com/watch?v=CnC_u225o6E&list=HL1403718581&feature=mh_l olz
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