A Question for the Wise One Who Shall Not Be Named

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  • george
    Captain
    • Dec 2010
    • 727

    A Question for the Wise One Who Shall Not Be Named

    Hello Sir.

    I have a rather small side project as a distraction from my main sub project. I have a R.C P.T Boat that I would like to have Launch tube torpedoes from it.

    What I thought is that I make one copper pressure tank for the propel and then with the use of a servo and switches move the servo one direction and one torp. is launched then move the servo the other direction and the other switch is triggered and the other torp. is launched. I would like just a fast blast of propel to expel the torp. and not empty the pressure tank after both torps. are launched. The copper pressure tank is to only hold the gas to push the trop. out of it`s tube and the torps are electric powered.

    How could this be done? Pictures, drawings any help would be appreciated. Space is an issue, working on a 1/35 class of boat.

    Thank You.

    George
    Last edited by george; 05-18-2014, 07:59 PM.
  • He Who Shall Not Be Named
    Moderator
    • Aug 2008
    • 12508

    #2
    What you need is a 'poppet-valve'. It administers a short blast of compressed gas. Just what the doctor ordered.

    M
    Who is John Galt?

    Comment

    • redboat219
      Admiral
      • Dec 2008
      • 2885

      #3
      How about using springs to eject the torpedoes instead. More compact and simpler.
      Make it simple, make strong, make it work!

      Comment

      • george
        Captain
        • Dec 2010
        • 727

        #4
        Hello Again Wise one

        Thank You for your time and help. A further question on this subject. To make sure I understand the setup. One main brass propel source, two lines coming from it to each poppet valve and from each poppet valve a line to the torp. tube holding the torp. When pressed by the servo arm, the poppet releases a burst of gass to push the torp. out and on it`s way. The poppet is momentary, if the servo stays pushed on it, it will NOT empty the main propel tank like a spray can being held on?

        Where can I get the poppet valve and pressure cable small tubing and extras?

        Thanks Again for your Help.

        George

        Comment

        • george
          Captain
          • Dec 2010
          • 727

          #5
          Hello redboat219

          The problem with the spring method is it is mechanical and something is needed to hold the torp. in the tube until launch and more chances a breakdown. Also there is no visual effect or sound of torp. being fired.

          Thanks for the idea though.
          George

          Comment

          • redboat219
            Admiral
            • Dec 2008
            • 2885

            #6
            Manfred (MFR) uses spring to fire off his e torpedoes from his 1/35 Type VII and Type XXIII Uboats.

            The gas ejection system is more complicated and has more chances of breakdown than a mechanical system. You already have stated one problem with the gas system.

            If you're after the effects how about using a small amount of gunpowder behind the torpedo. Same thing they used on the 1:1 boats. Simple servo activated on/off switch to fire off the ejection charge.
            Last edited by redboat219; 05-18-2014, 10:26 PM.
            Make it simple, make strong, make it work!

            Comment

            • george
              Captain
              • Dec 2010
              • 727

              #7
              Hi redboat219

              Little problem with the black powder, police here in Canada would NOT be too happy with me.

              Comment

              • george
                Captain
                • Dec 2010
                • 727

                #8
                Hello again o wise one.

                Could you please tell me if I understand your "poppet valve" suggestion? If I understand it, I need ONLY one poppet valve, I guess that is a 3 way poppet valve? I port for gas in and two ports for output? As the servo pushes the button a little, one output port fires momentarily then as the same servo pushes the button further inward the second port fires momentarily.

                Is that right? OR what do I need to launch two torps. one at a time?

                ALSO what type of SMALL Poppet valve do I get? What is the brand name / type?

                Where can I get one?

                Thanks again for your help.

                George

                Comment

                • He Who Shall Not Be Named
                  Moderator
                  • Aug 2008
                  • 12508

                  #9
                  Originally posted by george
                  Hello again o wise one.

                  Could you please tell me if I understand your "poppet valve" suggestion? If I understand it, I need ONLY one poppet valve, I guess that is a 3 way poppet valve? I port for gas in and two ports for output? As the servo pushes the button a little, one output port fires momentarily then as the same servo pushes the button further inward the second port fires momentarily.

                  Is that right? OR what do I need to launch two torps. one at a time?

                  ALSO what type of SMALL Poppet valve do I get? What is the brand name / type?

                  Where can I get one?

                  Thanks again for your help.

                  George
                  No. You need a dedicated poppet valve per tube. Trouble is (I've been searching the Internet) I can not find one small enough for us -- likely the Froud numbers work against us as we reduce the size of the mechanism.

                  Try this: a dedicated 'impulse bottle' per tube, using a modified Schreader-valve as a firing valve. As you said, a single servo, tripping a firing-valve at each extreme of servo travel will work the two tubes. The impulse bottle being no more involved than a longer than normal flexible line between charge fitting (another Schreader-valve) and the firing valve, as all you want is enough impulse to poop the weapon out the tube, not launch it into orbit. I think this is your best bet.

                  The modified Schreader-valve (firing valve) looks like this,

                  Click image for larger version

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                  M
                  Who is John Galt?

                  Comment

                  • Sublime
                    Lieutenant, Junior Grade
                    • Jan 2014
                    • 48

                    #10
                    There are tiny .22 RF blanks called ACORN, various reloading components called primers for pistol and shotgun. The problem with that is you need a firing pin/hammer. Remington Arms Company used to sell electrically fired primers at one time, don't know if they still do.

                    Comment

                    • redboat219
                      Admiral
                      • Dec 2008
                      • 2885

                      #11
                      Ok. How about using a solenoid valve like those from Clippard or RC-Subworkshop. Another alternative is those spool valves used to work rc aircraft landing gear retracts. Robarts is a well known brand.
                      Make it simple, make strong, make it work!

                      Comment

                      • george
                        Captain
                        • Dec 2010
                        • 727

                        #12
                        Hello

                        A PM has been sent to "He Who Shall Not Be Named"

                        George

                        Comment

                        • trout
                          Admiral
                          • Jul 2011
                          • 3561

                          #13
                          George,
                          Do you mean a real PM from the forum or an email? cuz, I do not think M uses the PM portion of the forum.
                          Peace,
                          tom
                          If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.

                          Comment

                          • george
                            Captain
                            • Dec 2010
                            • 727

                            #14
                            Hi Tom

                            I sent M a PM through the forum. I will try an email also.
                            Thanks
                            George

                            Comment

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