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Thread: RMS 24/40 igniter ?

  1. #1
    Join Date
    17th February 2010
    Location
    Valley of the Sun ,AZ
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    17

    RMS 24/40 igniter ?

    First things first .
    This is my first post to The Rocketry Forum. It has been a great source of info for me.
    I'm finally making my move to mid power.
    My ? is about the procedure for the insertion of the igniter int a rms 24/40 f24-7w reload. The instructions say to insert the igniter all the way into the load until it bottoms at the delay element. Is this correct ? Seems to me that the delay would ignite at the same time the propellant does.
    Please explain.

  2. #2
    Join Date
    18th January 2009
    Posts
    609
    That is correct.

    The delay does ignite at the same time as the propellant. The propellant burn time is factored into the delay.
    Bob Harrington
    NAR #62740 L1
    AMA #46042
    CMASS Member

  3. #3
    Join Date
    18th January 2009
    Location
    UK- Worksop
    Posts
    1,584
    Quote Originally Posted by BobH48 View Post
    That is correct.

    The delay does ignite at the same time as the propellant. The propellant burn time is factored into the delay.
    Bob's correct, also if this is a first with the reloads then you might want to rough up the C slot where the igintor head sits, helps the reload light.
    UKRA 1547
    L2
    Midland Rocketry Secretary

  4. #4
    Join Date
    20th January 2009
    Posts
    100
    Quote Originally Posted by compass1 View Post
    First things first .
    This is my first post to The Rocketry Forum. It has been a great source of info for me.
    I'm finally making my move to mid power.
    My ? is about the procedure for the insertion of the igniter int a rms 24/40 f24-7w reload. The instructions say to insert the igniter all the way into the load until it bottoms at the delay element. Is this correct ? Seems to me that the delay would ignite at the same time the propellant does.
    Please explain.
    I've also found it nearly impossible to insert a copperhead into the slot, and tend to put it in while building the motor. I don't see this as significantly more dangerous that putting Estes ignites into blackpowder motors before checking in, and would never do this with a larger motor. Feel free to correct me if this sounds stupid.

    Sam

  5. #5
    Join Date
    18th January 2009
    Location
    Sittin' on the Group "W" bench...
    Posts
    422
    Building the igniter in when assembling the motor is actually the procedure recommended in the instruction sheet for some of the smaller motors, IIRC. I never felt very comfortable with that. Accidental ignition has nothing to do with it, though. A copperhead is no more likely than an Estes igniter to fire unintentionally.

    If the igniter won't slip up through the nozzle of the motor after assembly, I worry about it not blowing out through the nozzle properly after ignition, and causing the case to over-pressurize. The fine threads on the 18 and 24mm cases don't look like they have a lot of margin before they let go (as designed).

    For the motors with really small nozzle throats, I generally select an igniter with very little pyrogen, and a correspondingly small diameter. Sanding the grain slot and painting a bit of pyrogen into the top of the grain helps ensure ignition, even with a deliberately selected "wimpy" igniter. Quest Q2G2s work reliably when used like this, and slip easily into the smallest motors even after assembly.
    Bob Weiss
    NAR #88301 L2
    N2IXK

  6. #6
    Join Date
    18th January 2009
    Location
    Holyoke Ma
    Posts
    301
    I find that when you have an igniter that doesn't fit into a reload it is mainly due to the pyrogen head being a bit on the big side I will put it in while building the motor and have had no problems.Once it has ignited and the motor is coming up to pressure if it is a copperhead most of the copper leads will be vaporized so they don't have a chance to block the slot and have it over pressurize if it was a firstfire jr I might worry a bit but again once the pyrogen has burned there isn't much left that can get in the way of the leads to cuase a problem.
    Andy Gadbois
    CMASS Member

    NAR 88064
    Level 1 Loc Hyperloc 835 I218R

  7. #7
    Join Date
    18th January 2009
    Location
    Illinois
    Posts
    1,176
    I just want to say welcome to TRF!
    Lisa

  8. #8
    Join Date
    26th July 2009
    Location
    Fishers, Indiana
    Posts
    696
    Thanks for posting. Good question! I don't have anything to add but I look forward to reading and responding to your future posts.

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