Jump to content


Photo

Full Auto

can it be done

37 replies to this topic

#26 The Inventor Guy

The Inventor Guy

    Member

  • Members
  • 290 posts
  • Location:Adelaide, Australia

Posted 17 April 2006 - 07:29 PM

The RF20 uses compessed air for this task, while the dart is propelled by a spring/plunger system.

No...
The RF20's piston is only spring loaded to regulate the amount of air that passes through. It is merely a modified blow-forward valve. The darts are in fact shot out by the compressed air which passes through the piston to cycle the turret/clip.

The RapidFire 20 system is really not difficult to replicate.

-Tidge.
  • 0

Also active on NerfHQ as Tidge.

#27 boltsniper

boltsniper

    Member

  • Contributors
  • 591 posts

Posted 17 April 2006 - 07:46 PM

I beg to differ, but if you can offer some proof to prove me wrong than, by all means, present it. But if it does operate the way you describe, then why will a dart fire if the trigger is not depressed. For instance, when the bladder gets low, you get pull the trigger and watch the spring compress, then release the trigger.

Edited by boltsniper, 17 April 2006 - 07:47 PM.

  • 0

#28 CaptainSlug

CaptainSlug

    Resident Mad Scientist

  • Administrators
  • 4,761 posts

Posted 17 April 2006 - 08:40 PM

what of you used a crank, like the old days. you could use a crank with gears to pull back the plunger and at the end the plunger would be relaese.

Gears cost alot to make or buy and a crank is hardly and effective trigger. Nevermind the fact that a crank is awkward for a handheld weapon.
I just figured out a mechanical method of regulating tank pressure so that solves the problem of have a motorized pump charging the tank. I need to figure out a valve cofiguration though. The one I have right now is only semi-auto (one trigger pull equals one shot).
  • 0
The little critters of nature, they don't know that they're ugly. That's very funny, a fly marrying a bumble bee. I told you I'd shoot, but you didn't believe me. Why didn't you believe me?

#29 The Inventor Guy

The Inventor Guy

    Member

  • Members
  • 290 posts
  • Location:Adelaide, Australia

Posted 19 April 2006 - 04:00 AM

I beg to differ, but if you can offer some proof to prove me wrong than, by all means, present it. But if it does operate the way you describe, then why will a dart fire if the trigger is not depressed. For instance, when the bladder gets low, you get pull the trigger and watch the spring compress, then release the trigger.

I have some pictures of a cut-open PowerClip valve on the other machine which I'll upload to my photobucket later.
Until then, I will describe the valve system the best I can.
1) The trigger is pulled allowing the compressed air to pass through to the piston.
2) The compressed air pushes back on both seals which in turn compresses a spring behind the rear seal and a compression spring connected to the front-most seal.
3) The air is still flowing into the piston while the springs are compressing more and the piston mechansim grows in length.
4) The rear spring is close to full compression and the front spring is now compressed as far as it can, so the shaft now has no compression - the front seal pulls back.
5) Now the front seal has removed itself from the exhaust hole, the air rushes out the exhaust tube.
6) The pressure inside the mechanism has dropped considerably, thus allowing the rear spring to expand again, which in turn pushes the front seal back against the exhaust hole and sealing it.
7) THis cycle continues while the trigger is depressed as there is a constant air flow to the mechansim until the trigger is released, thus cutting off the air supply to the mechanism, thus stopping the cycle.
7a) The cycle will only stop when there is no-longer enough pressure in the system to compresses the rear spring.
I do believe I had just adequately described a RapidFire20's mechanism which relies on a constant source of air pressure. Springs are not compressed back to allow a plunger to compress more air and shoot the dart, but rather the springs are there to allow a regulated amount of air through to shoot the darts.

Satisfied? If not, I will carry on and post cut-away photographs of a PowerClip's mechanism.

-Tidge.
  • 0

Also active on NerfHQ as Tidge.

#30 taita cakes

taita cakes

    Member

  • Members
  • 943 posts

Posted 19 April 2006 - 07:07 AM

I thought you were talking about the RF20 originally, and have now moved onto the PC?

Anyway Tidge, never forget to get to work on my electronics ASAP man. Much love.
  • 0
Oh Kentucky, you are so fuggin awesome...

#31 CaptainSlug

CaptainSlug

    Resident Mad Scientist

  • Administrators
  • 4,761 posts

Posted 19 April 2006 - 06:41 PM

Here's a rouch diagram of what I've come up with after several says of thinking. It would require motorization, but on a much smaller scale than CSHG. The electric pump would be optional, although it would make things much easier because the gun would automatically prime itself and keep itself at a mechanically set pressure level.
Posted Image
Cycle breakdown
1. 12V motorized piston pump charges the main tank and charging tank to a specified pressure.
2. The pressure on the main tank depresses the spring-loaded diaphragm to the point that it triggers the Normally-closed switch, turning the pump off. The capacitor between the switch and the pump makes sure that the pump keeps pumping just long enough after the switch is triggered that the diaphragm is pushed enough to keep in contact with the switch. The loadrate of spring would be chosen based on the required pressure.
3. The solenoid starts pulling the valve-plunger back
4. The valve plunger seals the charge tank close and then exposes the main tank to the breech actuator.
5. The breech actuator is pushed back 2.5" or 3" to close the breech.
6. As the valve-plunger hits the end of the 1/2" pull the charge tank is exposed to the barrel and the dart fires.
7. The solenoid turns off and the valve-plunger travels forward.
8. The breech-actuator is sealed off and the charge tank pressure is equalized to the main tank.
9. The breech-actuator depressurizes and spring-returns to the open position, this puts a new dart in the barrel.
10. Cycle repeats

Now simply put the solenoid on a Pulse-Width Modulation circuit controlled by the trigger and you can vary the timing to get the highest possible cycle length. The trigger will simply control the On/Off of the Pulse-Width Modulation that controls the solenoid firing.

Edited by CaptainSlug, 19 April 2006 - 10:19 PM.

  • 0
The little critters of nature, they don't know that they're ugly. That's very funny, a fly marrying a bumble bee. I told you I'd shoot, but you didn't believe me. Why didn't you believe me?

#32 The Inventor Guy

The Inventor Guy

    Member

  • Members
  • 290 posts
  • Location:Adelaide, Australia

Posted 19 April 2006 - 08:37 PM

I thought you were talking about the RF20 originally, and have now moved onto the PC?

Anyway Tidge, never forget to get to work on my electronics ASAP man. Much love.


The PowerClip and RapidFire20 mechanisms are very much the same, almost indentical with the exceptions of the size-scale and the front seal on a RF20 is flexible as opposed to the flat front seal of the powerclip.

CaptainSlug, that is a very good design there.
I had a thought recently of a similar valve system after looking at a few Autococker Paintball markers.

-Tidge.
  • 0

Also active on NerfHQ as Tidge.

#33 boltsniper

boltsniper

    Member

  • Contributors
  • 591 posts

Posted 19 April 2006 - 09:28 PM

If that is the case, Tidge, then explain to me how the semi/auto selector works without hindering range substantially.

Slug, that's a very impressive system you got there. Any plans on attempting it? Dialing in those springs might be tough.
  • 0

#34 CaptainSlug

CaptainSlug

    Resident Mad Scientist

  • Administrators
  • 4,761 posts

Posted 19 April 2006 - 10:11 PM

Slug, that's a very impressive system you got there. Any plans on attempting it? Dialing in those springs might be tough.

Thanks. I don't have any plans for it at present and if someone feels the need to beat me to it they're more than welcome. The spring selection would require some simple calculations with the desired pressure level pushing on the surface area of the diaphragm head. So Desired-Pressure / Square-Inch-Area-Of-Diaphragm-head = Spring Compressed load.
You only need enough actuation to trigger the momentary switch at the right point.
The simple-stupid method of placing the switch in exactly the right place would be to simple seal the main tank with the diaphragm in place, pressurize it to the right level of PSI, then mount the switch in it's triggered position.

The breech actuator spring could be really weak (2 to 10lb) but would need to have the right travel length.

I'll try to work up a more detailed CAD drawing once my homework load lightens.

Edited by CaptainSlug, 19 April 2006 - 10:21 PM.

  • 0
The little critters of nature, they don't know that they're ugly. That's very funny, a fly marrying a bumble bee. I told you I'd shoot, but you didn't believe me. Why didn't you believe me?

#35 LastManAlive

LastManAlive

    Member

  • Members
  • 686 posts
  • Location:West Virginia

Posted 19 April 2006 - 10:27 PM

Air source>ball valve> barrle with spring fed clip system (no bolt or anything)

That is the best idea I can cough up. You could maybe use a solenoid valve in place of the ball, but it would be bulky to me.

Range would suck a monkeys nut and it you would need a hella huge airtank on your back to supply air. What, a tow pounder at least?

That's the simplest way I guess.
  • 0
He came, He saw, and he conquered... But where did everyone go?

#36 boltsniper

boltsniper

    Member

  • Contributors
  • 591 posts

Posted 19 April 2006 - 11:47 PM

I know the calculations are simple, I was more referring to actually finding springs to fit the specs you need...
  • 0

#37 CaptainSlug

CaptainSlug

    Resident Mad Scientist

  • Administrators
  • 4,761 posts

Posted 20 April 2006 - 12:12 AM

Mcmaster part# 9657K16 would work if the diaphragm head were one cubic inch in exposed surface area.
2-3/4" L
7/8" Od
.148" Wire OD
Load: 94.28 lbs
Deflection at Load: .47"

The diaphragm head needs to be no larger than 1 cubic inch in surface area (roughly 1.125" diameter) otherwise you start needing a heavier and heavier spring. Now I have some definite dimensions to work with when designing that part.

Edited by CaptainSlug, 20 April 2006 - 12:34 AM.

  • 0
The little critters of nature, they don't know that they're ugly. That's very funny, a fly marrying a bumble bee. I told you I'd shoot, but you didn't believe me. Why didn't you believe me?

#38 The Inventor Guy

The Inventor Guy

    Member

  • Members
  • 290 posts
  • Location:Adelaide, Australia

Posted 20 April 2006 - 03:10 AM

If that is the case, Tidge, then explain to me how the semi/auto selector works without hindering range substantially.


:wacko: I thought you of all people should understand this one, boltsniper.
The dial on the RapidFire20 is basically a ramped arm which presses on an air-flow control valve. Essentially, this valve never closes but merely restricts the speed of the flow of air to the system while still allowing the pressure to equalise.
When the dial is selected to Semi-automatic, the arm comes off of the valve, thus closing it (as far as it does). As I said before, this merely acts as a flow restrictor. If you to continue to hold the trigger in semi-auto mode, it will still fire automatically, but very slowly, as the flow of air to the system has only been reduced.
When the dial is selected to Fully-automatic, the arm depresses the valve rod causing the valve to open much more thus allowing a higher flow. When the trigger is pulled, the flow of air to the restrictor is much quicker thus making it seem instantaneously automatic fire.

Is this infomation sufficient?

-Tidge.

Edited by The Inventor Guy, 20 April 2006 - 03:14 AM.

  • 0

Also active on NerfHQ as Tidge.


0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users