SpudFiles

There seems to be several questions about how to place a spark in the center of a hybrid (or combustion). I did it on my hybrid launcher, without tapping into the chamber, fairly easily, and I figured I would post a how-to.

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Obtain the materials
1 - metal coathanger
1 - drill bit slightly larger than the coathanger
2 - pieces of heatshrink tubing, or electrical tape
1 - 1/2" steel pipe cap
1 - 1/2" steel pipe nipple, close
1 - JB Weld or other strong epoxy

Obtain the tools
1 - pair of needlenose pliers
1 - file or grinder
1 - lighter
1 - drill + drill bit slightly larger than the coat hanger diameter

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1: Drill two holes, side by side but not touching, in the end of the pipe cap.

2: Clip the coat hanger into two pieces, making each piece about 1 inch longer than half the chamber (if the chamber is 12" long, the pieces should be 7" long as 12 / 2 + 1 = 7).

3: Use the grinder or file to sharpen one end of each coat hanger. Use the needlenose pliers to put a loop in the opposite end.

4: Clip several 1inch pieces of heatshrink tubing.

5: Slide the heatshrink tubing over the coathanger until it hits the loop and heat it up so that it shrinks snugly against the coathanger. Repeat this process until the hanger + tubing will slide through, but fit snugly inside, the holes in the pipe cap.

6: Slide the coathangers into the holes, making sure the heatshrink tubing is touching the cap and not the wires. The pointed ends should go into the chamber.

7: Fill the cap with JB Weld no less than half full.

8: Tighten the nipple on to the cap and allow the JB Weld to dry.

9: Bend the pointed ends closer together.

10: Place it on your launcher

11: Connect the exposed (looped) ends of the coathangers to the sparking system.

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Options:
- This is designed for a hybrid launcher but can be used for any combustion type launcher.
- This is not limited to using only 1/2" steel pipe fittings.
- PVC can be used instead of steel fittings. If this is the case (and assuming a hybrid is not being built), the heatshrink tubing is not necessary.

Not sure why this topic never received any replies, I think it's a pretty solid alternative to spark plugs. Since I can't be bothered finding spark plugs which are close enough in thread diameter for me to re-tap a brass fitting and then epoxy it in (like I did on my first hybrid), I gave this a try. Seems to work so far.

Only thing i'm worried about is the epoxy being damaged by the combustion. I just checked the JB-Weld on my first hybrid at the spark plug and half of it has been wasted away. That's probably from about 40-50 firings. I'm using araldite this time, maybe it'll be better.

I made a solid JB weld plug inside a 3/4"-1/2" bushing and the spark plug method, I have fired at 5x, and it holds true, but Its only been two or three shots

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This is what mine ended up looking like:


Had no heat shrink (and it's damn expensive) so I just used electricians tape.

THanx a ton mate....really needed help with the spark plugs!!!!
This just solved my problem.....and a pretty good and east to understand diagram!!!

CHEERS