Thin ejection charge canisters for 2.6" body tube?

I'm building a Madcow DX3 2.6" with dual deploy. Space is really at a premium when trying to fit two ejection charge canisters, the eyebolt, the nuts for the sled rods, and two power connections on top of a 2.6" bulk head. I need some thin ejection charge canisters (length shouldn't be a problem). Any recommendation? I do prefer reusable, attached canisters to latex glove fingers and other one-time use solutions.

Empty handgun ammunition brass? Knock out the primer, and run a small screw thru the flash hole to attach to a bulkhead. For a 2.6" a/f, I'd say a 9mm should hold enuf 4F. If you want a little more, maybe use a 38 Special. Put the e-match in, pour in the 4F, and cap with a tuft of dog barf and some masking tape.

cherokeej said:

Empty handgun ammunition brass? Knock out the primer, and run a small screw thru the flash hole to attach to a bulkhead. For a 2.6" a/f, I'd say a 9mm should hold enuf 4F. If you want a little more, maybe use a 38 Special. Put the e-match in, pour in the 4F, and cap with a tuft of dog barf and some masking tape.

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I do this a lot with my minimum diameter rockets, even use rifle shells for a longer canister when flying over 20k ft.
One caution, put a loop in the wire at the top of the shell, so it doesn't lay on the sharp lip. You wouldn't want it to short during thrust.

I used 30-06 cartridges for my Wildman Jr. I cut them off below the bottleneck, drilled the primer hole for a #4 screw and rounded the cut edge to minimize the risk of cutting wires. I tried handgun cartridges, they're lighter but the case walls are too thin to rounded over the edge.

Cartridges are the way to go.

I use 38s in 2" tubes, and 9mm or 45 in ~2.5" tubes. I place an ematch on the powder, pack it around with wadding so that the wire is sticking straight out the middle, then electrical tape it so the leads never touch the rim. Also, it wouldn't hurt to put a thin piece of tape over the contacts at the head of the ematch so it doesn't short against the cartridge wall.

Don't need a container. Just use masking /duct tape. You will be surprised by how simple and efficient it is.

+1 on the duct tape. I did this on a smaller rocket with limited space and it worked great! You should give that a try.

Just be careful about having the tape charge too close to a paper body tube. Holes have been known to be blown through.

I used .45 brass for my BT-80 av bay.

I've been having good success with Tygon clear tubing with hot glue end plugs on my 1.5" fiberglass rocket. Not only is space on the bulkhead at a premium, so is space anywhere in the parachute bay. The 1/4" tubing is flexible, so it just conforms to whatever corner the chute and shock cord push it into. I've used larger diameter Tygon in up to 4" FG body tubes with charges up to 3 grams Pyrodex P. Once a charge size is established, it has never failed to shear the pin and open the rocket.

I might not try this on a cardboard rocket.

Now I know what to do with the 50BMG brass I have!

I used 1/2 inch PVC pipe.
It's a little tight, but works for me!



Thanks,

Igotnothing said:

Not only is space on the bulkhead at a premium, so is space anywhere in the parachute bay. The 1/4" tubing is flexible, so it just conforms to whatever corner the chute and shock cord push it into.

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^This.

Long, metal, pointy canisters effectively shorten your bay and run the risk of tearing your chute. Tubing, vials, masking tape, and glove tips will conform to available space. I generally point the vial down the tube, but even when they fall sideways, I have never damaged a cardboard tube, even wimpy 2.6" LOC tubes. If you are blowing holes in your cardboard airframe, then you are likely doing something else wrong.

2.6" bulkhead has plenty of room. Perhaps you have too much "stuff." Here is a perfectly fine 2.6" bulkhead on my Madcow DX3. No honking big forged eyebolt (bent wire is fine), #8 or #10 threaded rods (not 1/4"-20), no quicklink (tie a knot), centifuge vial charge (no fixed canister), and my favorite thing of all, one terminal block for one and only one altimeter.

I like simplicity, that right there is about as simple as it gets. My next will be similar but without the terminal blocks.

My usual bulkhead configuration, both charge wells are aluminum round bar stock center drilled with a drill press (put the barstock into the chuck and lower onto the stationary bit), the one on the left is 1/2" bar stock with a .375" hole and the one on the right is .375" round stock with a .25" hole the two charge holders hold about 1gram each. the one on the left is for a 3" rocket the one on the right is for a 1.88" airframe coupler.