Looking for 29 mm Minimum Diameter Solution

Discussion in 'The Watering Hole' started by cwbullet, Nov 13, 2019.

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  1. Nov 13, 2019 #1

    cwbullet

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    I am looking for a solution - 3d printed or not.

    I need to add a shock cord mount to the tube that will allow for ejection and it not mounted to the motor tube. Any ideas?
     
  2. Nov 13, 2019 #2

    rharshberger

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    3D print an AeroPack or GLR style min diameter motor retainer (except its retaining a shock cord and not the motor) that's ported to allow the ejection charge gas to pass through. An eyebolt could even be built into the design or a loop of kevlar around a "bar" in the center of the ring.
     
  3. Nov 13, 2019 #3

    cwbullet

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    I am afraid 3/d printed parts would melt with ejection gases.
     
  4. Nov 13, 2019 #4

    BABAR

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    Mount a wire fishing leader to your plastic fin can (it will be ejection heat proof.). Feed it up your tube and attach the remainder of shock cord high up away from ejection flame.
     
  5. Nov 13, 2019 #5

    Tyler P

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    Little tiny baffle assembly with a little eye-bolt?
     
  6. Nov 13, 2019 #6

    dhbarr

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    Been meaning to sketch out a printable assembly that allows an off-center faucet aerator to be inlined. Recovery anchor would pass through at the wall, wire basket most of the remainder, petg epoxies in.
     
  7. Nov 13, 2019 #7

    markg

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    I lasercut this out of wood and mounted it with setscrews in my 38mm Blackhawk. I'm sure you could 3D print something similar and mount with epoxy. Sorry, I don't have a picture of the shock cord attachment, but basically I took kevlar long enough to reach the top of the BT and tied loops around each side of the mount in the relief cuts.

    CJ did something similar with coupler in the Blackhawk instructions and just epoxied the kevlar to the coupler.

    Also, I 3D print ejection charge holders for DD and have not yet seen any deterioration, flown one set 5 times now.

    cheers
    Capture.JPG
     
  8. Nov 13, 2019 #8

    dr wogz

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    Chuck,

    Drill a hole thru the BT, and insert a chopstick. (Drill /mount it high enough to clear whatever motor you use). Glue it in place & sand smooth the stick on the outside / to match the air-frame. Tie your shock cord to that..
     
  9. Nov 13, 2019 #9

    heada

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    I've done the same but with carbon fiber tubes. I got them for dirt cheap from Gander Mountain by asking for cut-offs from carbon fiber crossbow bolt shafts.
     
  10. Nov 13, 2019 #10

    dr wogz

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    do they whistle? Being a hollow / open.

    One's man's garbage is another man's treasure! good use of off-cuts!

    I've done that with a few sign makers I've worked with, ask them for their vinyl off-cuts & trimmed parts. I had at one point a lot (I mean a LOT!!) of sticky backed vinyl in a lot of colours! I still have some reflective stuff, typically use don Cop cars & ambulances.. Great for on bike helmets & the bike itself!
     
  11. Nov 13, 2019 #11

    heada

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    I fill the ends with epoxy and sand it smooth so you can't tell its even there. I got the idea from Darrell Mobley when he built an Estes D Region Tomahawk that he upgraded to 29mm.
     
  12. Nov 13, 2019 #12

    skydog

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    I often use a loop of Kevlar rope. Tie knot in each end, fray ends, embed knots in copious amounts of epoxy inside the body tube. LOC recommended this in some of their kits, and it's worked well for me. Or, cut a notch in a centering ring, glue and epoxy shock cord to ring, push ring way down deep. 2019-02-13 21.41.10 (Medium).jpg
     
  13. Nov 13, 2019 #13

    manixFan

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    I've done the same thing - rod thru the body tube. If it's a fiberglass body tube I use stainless steel rod epoxied in place, and then cut off with a Dremel and sanded using a sanding drum on the Dremel. Very stout.


    Tony
     
  14. Nov 14, 2019 #14

    cwbullet

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    Interesting ideas. I will give a couple a try.
     
  15. Nov 15, 2019 #15

    grouch

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    I did the same with a carbon rod through a section of Blue Tube. The rod snapped on its first flight and I lost the recovery train and a nose cone.
     
  16. Nov 15, 2019 #16

    manixFan

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    Yep, that's why I use a steel rod.


    Tony
     
  17. Nov 15, 2019 #17

    jqavins

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    These are more or less the same thing, and exactly the thing I was thinking. Replace "3D print..." with "Construct with the material(s) of your choice..." Being a functional baffle as well as shock cord mount it kills two birds with one stone.
     
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  18. Nov 15, 2019 #18

    dr wogz

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    The main thing here, is where you attach the cord. If in the center of the rod, likely to break. Near the attachment point to the tube less likely..

    Jarrett, how thick was the rod? what was the span, and how much "stuff" did you have in your recovery train?
     
  19. Nov 15, 2019 #19

    cwbullet

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    I may make the couple gadget. I just was thinking about options. I may order them of someone has a sale I am interest in. I thought about the bad cow kit from today.
     
  20. Nov 15, 2019 #20

    Tyler P

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    Yeah, a little ply bulkhead with holes drilled in it and a small eye-bolt in the center. I do this on most of my couplers. Make a nice little baffle canister and attachment point. A Rocketarium Black Brant kit I built came like that and I really like it, so I've put that into all of my builds so far.
     
  21. Nov 15, 2019 #21

    cwbullet

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    Bulkhead may prevent you from using motor deployment.
     
  22. Nov 15, 2019 #22

    Tyler P

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    Not if you drill it to make it into a baffle. ;)
     
  23. Nov 15, 2019 #23

    BDB

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    If you design a part in CAD, I could print an anchor for you using a high temp resin on my SLA printer.
     
  24. Nov 17, 2019 #24

    rokit

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    A variation of the rod thru tube method. Cut a half inch section from a 29mm SU motor for the tube. Use a finishing nail, cut flush with the outsides of the motor casing, for the rod. At the time I had some wire fishing leader, so I used that for the shock cord to attach to.

    Mike

    [​IMG]
     
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  25. Nov 17, 2019 #25

    cwbullet

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    This is exactly what I am going to do.
     
  26. Nov 17, 2019 #26

    grouch

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    Oh I have no idea. That was years ago. I remember it being a carbon aluminum arrow shaft and that's about all I recall. If you are not failing, you are not learning and all.
     
  27. Nov 17, 2019 #27

    manixFan

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    That’s a great variation of the method discussed. I knew saving a few 29mm SU motors was a good idea.

    Tony
     
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