Propane/Oxygen Gun Simulator Schematic

Discussion in 'The Projects Forum' started by jgrupczy, Dec 24, 2015.

  1. jgrupczy

    Thread Starter New Member

    Dec 19, 2015
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    I was looking for this and found an OLD thread and the schematic was missing. On top of that I was told that it was so old that I should start a new thread. I am not trying to re-invent the wheel, so why not use a circuit that has been tried and true! Please help if you can.
     
  2. #12

    Expert

    Nov 30, 2010
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    Propane comes in a tank. Oxygen is in the air around us. Car ignition coils make sparks.
    Am I starting off too basic? Give us some help here. Good questions get good answers.
    Maybe even copy the address of the previous Thread into your post so we can see how many spokes the other wheel has.
     
  3. JohnInTX

    Moderator

    Jun 26, 2012
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    Can you post a link to the old thread?
     
  4. jgrupczy

    Thread Starter New Member

    Dec 19, 2015
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    For the life of me, now I cannot find the old thread.....

    AAC Fanatic. I bvelieve it was one of YOUR old posts and you were having some issues with a different type of coil.....???? Now I cannot find it!! Getting old.....

    I am a volunteer on the USS Alabama and a member of their Living History Crew. We are going to have another re-enactmet late in February and another in April when some of the old original crew from WW II have thier annual reunion. Not many left. You can google it to see what we are up to.

    What we want to do is retro-fit some of the 20 mm Anti Aircraft guns with Oxy/Propane firing simulators. I am quite familiar with the system because we had 4 of our 40 mm AA guns retrofitted some years ago. Now we just want to do it ourselves. What I am lacking is a good circuit to control the two solenoid valves and fire the spark plug. I would appreciate any help you could provide.
     
  5. Wendy

    Moderator

    Mar 24, 2008
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    This thread is skirting the edge of our ToS (Terms of Service), but since no projectiles are involves I'll give it a by.

    Have you thought of using a piezo circuit, as found in a lighter or grill? You can buy them off the shelf, no batteries needed.
     
  6. jgrupczy

    Thread Starter New Member

    Dec 19, 2015
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    Thanks for your reply Wendy. Yes, NO projectiles are involved. Just a flash at the end of the gun and a lot of noise. Just for show. These have been used at many various military re-enactmens for years.

    Beyond just igniting the gas, you have to regulate how much of each of the gases are allowed into the chamber. This is done by adjusting the time the two solenoid valves are open and the gas pressure of each, Usually 4 to 1 on the existing guns. Then there is a delay for the gases to mix and finally the ignition of the gas. These have been around for years and I just want to get a good proven circuit design to start with.
     
  7. #12

    Expert

    Nov 30, 2010
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  8. #12

    Expert

    Nov 30, 2010
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    Not necessary if you aim the nozzles to force turbulence.

    Keep talking. Your ideas, your level of expertise, your memories of how it was done...
    We're sucking wind here, and you are the only way to change that.
     
  9. jgrupczy

    Thread Starter New Member

    Dec 19, 2015
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  10. #12

    Expert

    Nov 30, 2010
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    69 posts is considered a long Thread here. We can usually get to the heart of the problem in less than 20...40 at the most.
    Right now, Christmas and Family are demanding the attention of most of us.
     
  11. jgrupczy

    Thread Starter New Member

    Dec 19, 2015
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    Yes, Merry Christmas #12 and to all that are trying to assist! The only "problem" is that I am looking for a good schematic. Once I get that, I can provide a complete diagram, build list, for a complete system. Thank you in advance for anything you can do.
     
  12. ronv

    AAC Fanatic!

    Nov 12, 2008
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    Just a question or 2, then I'll give the description a try.
    1- What voltages do you have to power the circuit?
    2- Would you happen to have a manufacture and part number for the valves you are using?
    3- What do you use as the trigger? A push-button or something fancier?
    4- Do you know what makes the spark in the current design or could we use a spark plug and ignition coil?
     
  13. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    5,699
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    This sounds like and probably is a potato canon. When hairspray went "green", they got rid of the chlorinated and flourinated hydrocarbon propellants and replaced them with a simple explosive gas, propane. I hate to admit it, but I have made such canons that will pop a potato over 400 yards. There is nothing sophisticated about the ignition. However, is the discussion of such within the TOS of AAC?

    John
     
  14. jgrupczy

    Thread Starter New Member

    Dec 19, 2015
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    Close but significantly different, but, like a potato cannon, it ignites a gas. NOTHING IS LAUNCHED!! That would be dangerous! This simply makes a lound noise!
    You can google it and look for "Machine Gun Simulator".

    1-It is powered by a 12v DC battery.
    2-The valves we are using are Part # 341115-12VDC on the 40 mm AA
    3-A simple push button momentary switch mounted on the handle to trigger the operation (one shot or continuous operation)
    4-We use a standard automotive coil like the AC Delco U505 or the Emgo 24-7512
    5-For the spark plug we use a Champion DJ7Y 14 mm or a 10 mm NGK CM-6 for tight space.

    I AM SURE THAT A CIRCUIT EXISTS IN MANY FORMS TO SEQUENCE THE OPERATION. THAT IS WHAT I AM LOOKING FOR. AGAIN, WHY REINVENT THE WHEEL.
     
  15. SgtWookie

    Expert

    Jul 17, 2007
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    This thread is NOT about a potato cannon. Please read post #4 where the thread originator informs us that they would like to simulate the firing of the USS Alabama's 20mm Oerlikon deck guns.

    What is the desired cyclic rate of fire? I believe that these guns were somewhere between 280 and 450 rounds per minute.

    It's been over a dozen years since I visited BB-60, and don't remember how they were configured; single or dual?

    Using accurate pressure regulators (like for gas welding) should eliminate the necessity of monitoring the gas pressure and varying the solenoid activation duration accordingly.
     
  16. jgrupczy

    Thread Starter New Member

    Dec 19, 2015
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    HI SgtWookie, Merry Xmas!

    Yes, the models on the ship were in that range but as we have found out with the 40 mm that we have converted on the ship, you can only use short bursts because the barrel gets very hot. We are shooting for is around 3 per second on the 20 mm guns.

    We have both singe and dual on the ship. But at this time we are looking to convert a few of the singles.

    Yes, we are using accurate regulators for the Propane and Oxygen. In addition, gas check valves. Both gas solenoid valves are controlled in parallel by the same control. We regulate the mixture by setting the propane to 10 PSI and the oxygen to 40 PSI.
     
  17. SgtWookie

    Expert

    Jul 17, 2007
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    Merry Christmas!
    Gee, 3 rounds/sec is only 180 rpm; the slowest standard rate of fire would be about 4.7 rounds/sec. Are you sure you would want to go that slowly?

    Although the sequence could be performed using timer ICs like 555's or 556s in conjunction with 4017s or the like, microcontrollers could greatly simplify the circuitry, with the potential of improving reliability.
     
  18. jgrupczy

    Thread Starter New Member

    Dec 19, 2015
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    Yes, would ike to start there, 3 to 4 rounds/sec, and see where we go. The 40's are single shot. Might be nice to convert them to auto also.

    A microctroller would be great but we do not posses the hardware/software to put something like that together. PC board, wire and soldering iron is what tools we have.

    I have used a 555 and dual 555's, 2n22's in my long ago (20 years ago) past but there is probably something new and new for the drivers for the solenods and coil. I just cannot believe that someone does not have a sequencer circuit in their back pocket. And, it probably does use some 555's.
     
  19. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    Do you have any specs. on valve ?
     
  20. jgrupczy

    Thread Starter New Member

    Dec 19, 2015
    26
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    I am looking but have NO luck so far finding a spec on the valve.... I will keep looking...
     
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