3" Mac Performance Modified Zodiac

[Banzai88]

...whereas I struggle to find #2-56 or even m2 bolts.

For future reference, most of our rocketry vendors carry them in a variety of quantities. Then there's always the universal supplier, McMaster-Carr. Links provided.

https://csrocketry.com/recovery-supplies/shear-pins/shear-pin-2/56.html
https://wildmanrocketry.com/collections/shear-pins/products/sheer-pins
https://macperformancerocketry.com/collections/hardware/products/hardware?variant=533801304083
https://www.apogeerockets.com/Building-Supplies/Misc-Hardware/Nylon-Shear-Pins-20-pack
https://www.mcmaster.com/screws/thread-size~2-56/material~plastic/material~nylon-plastic/

 

[Banzai88]

Pem Nut McMaster-Carr reference here: https://www.rocketryforum.com/threads/pem-nut-kits-and-shear-pins-kits.165818/page-2#post-2154846

 

[thzero]

https://www.mcmaster.com/screws/thread-size~2-56/material~plastic/material~nylon-plastic/

One has to like McMaster (or Grainger, etc) inventory... but doesn't have to like their insane and after the fact shipping.

 

[thzero]

Well I wanted to see how much volume I really needed for my ejection charge canisters, and well what better way than some math.

Did some searching online for FFFF (using Goex from my stash) trying to find out some volume vs weight, etc. but didn't really find good solid info. So I did some of my own research.

Did some calculations and then printed out a 1" cubic cylinder. Measured before and after with FFFF BP. Then more calcs.

Based on this, and some ejection charge calculators, looks like I start at .75g for drogue and .5g for main. However, based on experience with a similar sized rocket which was 1g and 1g respectively, I'm expecting the testing to end up about there. So I think I'll print out a set of 1 g canisters and then a a set of 1.5 g canisters and use them for testing.

 

[waltr]

So I think I'll print out a set of 1 oz canisters and then a a set of 1.5 oz canisters and use them for testing.

Do you mean 1 & 1.5 gram canisters?
There are about 28gm per oz.

 

[thzero]

Do you mean 1 & 1.5 gram canisters?
There are about 28gm per oz.

Yes, damnit, I did. Updated the post.

 

[thzero]

Ah, so the calculations worked good enough with about a .25" gap for padding, probably a tad much though, but for now to test until I know exactly what grams I want to use they'll work.

 

[thzero]

Nothing exciting here, but another tool that for drilling the shear pins; I ended up going with three #2-56 pins. What I did was use the drill bit for the #2-56 tap into the other tube, then drilled again through the body tube into the coupler. Then the body tube was re-drilled with a slightly larger drill bit just enough to let the pin slide through. Then of course tapped the coupler.

 

[thzero]

Internals for the AvBay with the bulkheads and the ejection canisters installed.



AvBay button'd up with the flags.

 

[thzero]

And nearly fully loaded - in this case I don't have parachutes, the two batteries or 54-38mm adapter.



Weights in at 83.65oz. which is within .5oz of what I expected so should be right about 93.34 fully loaded. Thats right about where I was shooting for. Little slow with the Cessaroni 411 than my standard target of 50 fps, but should be fine on my longer 9' rail.

 

[DerRedMax]

Any progress on this rocket to report?

 

[DerRedMax]

Internals for the AvBay with the bulkheads and the ejection canisters installed.

View attachment 558364

AvBay button'd up with the flags.
View attachment 558365

Where did you get the av bay sled? Looks very interesting for my future build.

 

[thzero]

Any progress on this rocket to report?

Er... no. Haven't bothered painting it, etc... just haven't had time and with weather coming and going around here can't really get the bike and fast car out of garage to be painting!

 

[thzero]

Where did you get the av bay sled? Looks very interesting for my future build.

My own custom design. It's flow in two other rockets

https://www.rocketryforum.com/threads/hpr-custom-build.162115/Which ended up being my L2 rocket.

And

https://www.rocketryforum.com/threads/my-l2-project.167503/Which ended up not being my L2 rocket, but did fly the same weekend.

This one was original printed on a Creality CR-6 SE in PETG, but I'm now printing most stuff on a Bambu Labs X-1 Carbon in PETG. I've recently switched to eSun PETG and seem to get better results than the previous Overture PETG with the X-1.