Building the Pneumatic System

Discussion in 'Weapons & Pneumatics' started by GeekSpeed, Apr 3, 2015.

  1. GeekSpeed

    GeekSpeed Active Member

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    Hey all.

    Does anyone have a good tutorial as to how to properly build the pneumatic system for fast gun ships? I am working on a class 3 cruiser and want to get all of the parts going for the cannon system. I am going to pass over the solenoid system for now and just go for poppet valves. I am trying to figure out what parts to buy and how to stick them all together. Thanks for any help!
     
  2. NickMyers

    NickMyers Admin RCWC Staff

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    Dual sterns? Did you want select fire or twin fire?
     
  3. GeekSpeed

    GeekSpeed Active Member

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    Sorry. Yes, dual sterns with twin fire.
     
  4. NickMyers

    NickMyers Admin RCWC Staff

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    Last edited: Feb 14, 2017
  5. GeekSpeed

    GeekSpeed Active Member

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    I think I just had a stroke.
     
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  6. NickMyers

    NickMyers Admin RCWC Staff

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    Its not that bad really. I can explain it better tonight after the kid is asleep
     
  7. mike5334

    mike5334 Well-Known Member

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    To simplify, the Mav-2 and MPAs can be removed and the MAV-3 and associated servo replaced with an electric solenoid and electronic switch. For better cannon reliability use a solenoid for each cannon triggered by a single electronic switch.
     
  8. SnipeHunter

    SnipeHunter Well-Known Member

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    It might be worth your while to reconsider solenoids. There are some rather cheap solenoids available these days so cost isn't the barrier it used to be, the pneumatic system is simpler which is helpful in a small boat where space and weight is key. This also means that the system has fewer failure/leak points. Solenoids and the needed electronics are very solid when used properly so there are reliability gains there as well. Performance is better which may not matter to you at the moment but likely will in the future. Overall if you think you're going to have/use this ship for a while it probably is easier/cheaper to do solenoids from the start rather than refitting it and adding them in. The setup would look something like this.

    [​IMG]
     
    Last edited by a moderator: Feb 14, 2017
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  9. irnuke

    irnuke -->> C T D <<--

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    Geek, just understand the basics: CO2 from regulator is fed to guns via either a Mav-2 gas-operated valve or an electrically operated solenoid. The Mav-2 is controlled by a Mav-3 pushbutton valve operated by a servo, the solenoid by a "firing board" triggered by your receiver.

    Hope this helps...
     
  10. Beaver

    Beaver 2020 Rookie of the Year Admiral (Supporter)

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    With a solenoid system, which firing board from BC would you need for dual sterns? And do you need one per solenoid or will one work for both?

    Thanks,
     
  11. SnipeHunter

    SnipeHunter Well-Known Member

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    You can run both guns off of one of the single firing boards.
     
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  12. NickMyers

    NickMyers Admin RCWC Staff

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    I'm going to preface this by stating that it is my opinion that if you do not already have the various bits and pieces to do a poppet setup that you should seriously consider a solenoid arrangement. If you're using something like the Spartan solenoids the increase in cost is not all that bad, and the removal of servos pushing valves in favor of waterproofed firing boards decreases bulk and mechanical complexity.

    Now, if you want to just run a single gun off a poppet, you connect your MAV-2 to some form of bulkhead to hold it in place, then you mount a servo such that its horn will press in the valve rod on the MAV-2. This will actuate the valve. You want the MAV-2 to be as close to the gun as possible because the line from MAV-2 to the gun is unpressurized until you fire, the onlonger it takes for this to fill, the more gas you use and the slower your weapon's response time.

    If you want to run 2 or more guns off of a single firing point, it would be logical to simply tee the output from a MAV-2, right? Only that doesn't work very well. What actually happens, besides taking longer to fire because you're now trying to fire two guns out of the same valve orifice cross-section, is that one gun will fire and then the pressure will bleed off through the open gun, and the second may fire, or may fire weakly.

    The solution? Use a MAV-3 and a pair of MPA-3s. The MPA-3 screws on to the MAV-2, over the part that the servo would actuate. When its input line is pressurized it shoves the valve rod to the open position, when its input line depressurizes it allows the MAV-2 to close. You then have your servo push a single MAV-3, whose output line is teed and connects to the two MPA-3s, providing the pressure to actuate the MAV-2s. The MAV-3 will depressurize its out-line once the valve closes, allowing the MPA-3s to close the MAV-2s.

    The simpler way?
    Hook a firing board or servo actuated microswitch up to a pair of solenoids. Press the button and BANG.
     
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  13. GeekSpeed

    GeekSpeed Active Member

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    Hmmm.... the solenoids sound like a better option. How does it change if I go fore/aft cannons? Do I need an additional firing board for that arrangement?
     
  14. NickMyers

    NickMyers Admin RCWC Staff

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    Depends. Some Firing boards will support both positions for a channel and two loads, and others will only support 1 position and one load. (multiple solenoids can be ganged for a single load if you need more than one thing firing at once)

    If you wanted to go with BC's boards ( FireControl )
    you should be able to use the dual board to support fore-aft fire as you'd rig a solenoid per load line so push the stick forward, fire bow, pull the stick back, fire stern. The single board you could only support one load and you have to pick the stick position on the board (with a dip switch), but if you only wanted dual sterns it would save you 10$.

    If you wanted to go with StrikeModel's boards ( Cannon Systems – Fast Gun | Strike Models ) I believe they only offer a two-load solution.

    Alternatively you could just use a servo to push the buttons on a pair of NO microswitches to trigger solenoids if you wanted to avoid the boards and really like servos and mechanical arrangement. I have this setup in my Derf and getting it setup was kind of annoying. The next microservo that randomly dies is going to herald me ripping them out and putting in boards.
     
  15. SnipeHunter

    SnipeHunter Well-Known Member

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    What Nick said, plus the hassle of ripping them out after the first event and switching to a dual stern setup.

    That's what happens the majority of the time when a rookie builds a cruiser with a bow gun and a stern gun. Bow and Stern singles sound great on paper and do you really want all of your guns facing aft anyway?, so thats what you end up building. Then you go to an event, see how we battle, what a cruiser's role is, the difference in damage between a single and a dual, etc, and switch to dual sterns.

    My first battle with my rookie Brooklyn Class cruiser had a single bow and a single stern after having been told more than once that dual sterns was the way to go. The second battle it had dual sterns which remained on it through the next 4 years of active use. (It still has them, but they probably dont work so great at this point....)
     
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  16. irnuke

    irnuke -->> C T D <<--

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    As said above, in this scale the ships move more by swinging their butt stern from side to side rather than carving the bow around a turn. So stern guns are far easier to aim + have the added benefit of keeping that squishy bow away from enemy guns & your cruiser poised for a quick getaway
     
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  17. NickMyers

    NickMyers Admin RCWC Staff

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    Yup yup. Dual sterns is what makes the good gravy :)
    Nobody is scared of a fore&aft cruiser, but people will get a little nervous about a well aimed dual stern cruiser backing down on their bow.
     
  18. rcaircraftnut

    rcaircraftnut Well-Known Member

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    I have an 8 unit BB and I am going to be installing 6 cannons. 2 in each bow turret and dual sterns. Sterns will be 75 rnd for a total of 7 units of gunnery. I am looking at doing a single servo activating 4 mav 2s for the bow guns and a single servo activating 2 mav 2s for the stern. This would allow me to eliminate the mav 3s and the 6 mpa3s saving around $90 in parts. Is there any reason why I shouldn't do it this way other than speed of fire, remember that this is a treaty ship. It isn't legal for fast gun so will never need the rate of fire over that which popits can provide.
     
  19. rcaircraftnut

    rcaircraftnut Well-Known Member

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    Also I have a bunch of servos so that cost is already covered.
     
  20. thegeek

    thegeek Well-Known Member

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    Most battlers start with a three or four unit ship. I have battled a 8 unit bb and it was a hand full. Just a thought.