Custom aluminum charge canisters

Ok, I'll admit it's a bit of an obsession.

I probably spend more time on AV Bays and recovery systems than any other part of my builds. I like the aesthetics and reliability of well constructed recovery systems with quality parts.

For the charge holders, I have used copper, and have many Blast Caps from GT. They were pricey, and as they became less available, I went back to the drawing board with the goal of making my own aluminum charge canisters.

My goals were to build canisters that could be customized to fit each rocket's needs, both in length and diameter; constructed of anodized aluminum for durability, and would also look good.


Here's what I ended up with...


Material: 6063 clear anodized aluminum tube, 5/8" OD, 0.495" ID (wall=0.065")

For this example, I cut a 2.5" length from the tubing




Next, drilled two small holes at 90 degrees...




Using a small bent pin (this example is a single finish brad from a brad gun...)
It's important to keep it off center, so i won't interfere with the mounting screw later.






Using thickened epoxy, filled about 1/4" to 3/8" of the bottom. Once it had cured, trimmed the pin, and drilled a hole for an 8-32 machine screw.





"Ok", you say, "But will they work? Is that epoxy plug going to stand up to the pressures of BP?"


Here's a ground test using 2 grams of BP in a RW Terminator 5:

[video=youtube;Z-M9kqK2i5c]https://www.youtube.com/watch?v=Z-M9kqK2i5c[/video]


And finally, here are the charge holders on the AV Bay after the ground test:

Nice looking clean Av Bay. Great job Bill

They look great. Are the holes on the sides for the wire to go through or am I missing something?

Reminds me of L.E.S. from Robbies rocket

WOW , Great job Bill

crossfire said:

They look great. Are the holes on the sides for the wire to go through or am I missing something?

Click to expand...

Right. This acts as additional reinforcement for the plug, and they are sealed by the epoxy. It may not be necessary, but I have not tested without it.

Please post more pics of AV bay. Very neat canisters.

Here's more info on the AV Bay.

This is for my L3 cert project, based on the RW Terminator 5. Using dual Marsa54L's, and the relatively new MrfBridge and MrfPyro gadgets.


The MrfBridges are shown here, attached to the Marsa's, both switched by Featherweight magnetic switches. The MrfPyro receivers are in the nose cone.




On the reverse side, a Real Flight GPS system, and the batteries for all devices. The end with the antenna is fixed, the other end is removed for assembling the AV Bay into the coupler. (This photo was taken with Blast Caps, before I swapped them out for my custom charge holders.)





Here's the side profile that shows the construction; behind the small aluminum channel in the center is a Schurter rotary switch for the GPS unit.




And finally, how the eye nuts are secured with safety wire to prevent them from coming loose during flight.

Ok I'm confused....

You have a forged eye-nuts on both ends for shock cord attachment with a threaded rod through the av-bay and wire wrapped safety wire on the antenna end, but no charge canisters on the antenna end. How does that end open? or haven't you installed the canisters yet?

"The MrfPyro receivers are in the nose cone."

Remote charges.

I hope you really don't just rely on zip-ties to hold you batteries....

Handeman said:

Ok I'm confused....

You have a forged eye-nuts on both ends for shock cord attachment with a threaded rod through the av-bay and wire wrapped safety wire on the antenna end, but no charge canisters on the antenna end. How does that end open? or haven't you installed the canisters yet?

Click to expand...

Fair question - good observation.
For this flight the AV Bay remains fixed between the aft and forward airframe - the aft eye nut (on the end with the antenna) isn't used other than for a backup retention to the 5 grain 75mm CTI case. Aft charge holders are not needed. I can add aft charge holders later if I decide to fly with a different configuration. Both ends will have a safety wire during flight to ensure the fasteners don't come loose during descent.

The apogee event deploys the drogue and nose cone from the forward airframe (as shown in the video). The Main event deploys the main chute at altitude from the nose cone, and is remotely initiated by the Marsa MrfPyro gadget.


Clear as mud? Need illustrations?

Pretty cool. It is a work of art.

Wow! Nice av-bay.

MrfPyro?

Kruegon said:

MrfPyro?

Click to expand...

https://www.google.com/search?q=Mrf...0j69i59j0l3.1566j0j7&sourceid=chrome&ie=UTF-8


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Kruegon said:

MrfPyro?

Click to expand...

In a nutshell, the Marsa54L can trigger a remote event using paired transmitter and receiver boards. The altimeter remains in the body, and triggers a recovery event at the other end of the harness in the nose cone, 25' away.

John makes some cool stuff, and I am looking forward to flying it.

Great products and great customer service.

Awesome idea about the safety wires. Will have to use that. Are your lids anodized and polished or painted? In one pic they look shiny. Just curious. Nicely done either way.

Mike

MikeyDSlagle said:

Awesome idea about the safety wires. Will have to use that. Are your lids anodized and polished or painted? In one pic they look shiny. Just curious. Nicely done either way.

Mike

Click to expand...

The av bay lids are black G10, hopefully available again soon from Madcow.

Ahh okay. Thanks
I have aluminum lids for the one I am about to start.