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Which AT 38/360 or 38/720 reloads for airstarts?

Posted: Sat Sep 01, 2018 9:34 am
by matthew
I'm considering dipping my toes into the multi-stage pond with a WMR 2.1" Jr setup for ARTDU19. I already have the 38/360 + 38/720 cases, and will probably grab another set so that I can choose between combos of 360/360, 720/360, and 720/720 setups. I will have the reload adapter spacers, so intermediate loads would be OK, too. I've only ever flown the I600R that lit fine from GSE. Are there propellants for these cases that are preferable for airstarting in the sustainer? Avionics will likely be Raven 3.

Loads:
https://ausrocketry.com.au/motors/reloa ... 8-360.html
https://ausrocketry.com.au/motors/reloa ... 8-720.html

Re: Which AT 38/360 or 38/720 reloads for airstarts?

Posted: Mon Sep 03, 2018 7:06 pm
by matthew
I think I'm just going to go with J500G and I357T loads. It will either be cool or very cool. :shock: :lol:

Re: Which AT 38/360 or 38/720 reloads for airstarts?

Posted: Tue Sep 04, 2018 12:19 pm
by drew
I'd probably steer clear of the J500G if I were you Matthew. Aerotech greens are pretty hard to light compared to other Aerotech propellant formulations.

If it were me I'd probably lean towards a white propellant myself for sustainer use.. So an I161 or I180 in the 38/360 casing or a J350 in the 38/720 casing.

Re: Which AT 38/360 or 38/720 reloads for airstarts?

Posted: Tue Sep 04, 2018 1:02 pm
by Sirbrad
Excuse my ignorance, but what is a WMR 2.1” JR?




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Re: Which AT 38/360 or 38/720 reloads for airstarts?

Posted: Tue Sep 04, 2018 1:44 pm
by drew
Sirbrad wrote:Excuse my ignorance, but what is a WMR 2.1” JR?

I suspect Matthew's referring to this kit.

https://wildmanrocketry.com/collections/wildman-junior/products/wildman-jr

Re: Which AT 38/360 or 38/720 reloads for airstarts?

Posted: Tue Sep 04, 2018 3:15 pm
by Sirbrad
How is this converted to two stage?


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Re: Which AT 38/360 or 38/720 reloads for airstarts?

Posted: Tue Sep 04, 2018 4:54 pm
by drew
Matthew will be able to answer better than I can but I would expect it would require 3 more fins, another motor mount, and a saw. :wink:

Re: Which AT 38/360 or 38/720 reloads for airstarts?

Posted: Tue Sep 04, 2018 5:09 pm
by vance2loud

Re: Which AT 38/360 or 38/720 reloads for airstarts?

Posted: Tue Sep 04, 2018 10:18 pm
by matthew
Thanks drew and crew. That is indeed the two stager I'll have a crack at.

drew, you're right. I'm going to use the J500G in the booster for a kick off the pad. For a first flight of the stack I had intended to use the I357T in the sustainer, but I'm sure a I161W will make me just as happy (especially if it lights!). :)

I decided I may as well buy a CTI 38/6GXL case so I can have something different and not a lot of the same cases. I am looking at using a 1115J530-15A (IM) in the sustainer for a second flight (presuming it's only a cool flight the first time around). I also have a 949J150-P (M) on my list. Again, it's easy to change. They're just numbers on my propellant order spreadsheet at this point. :)

Re: Which AT 38/360 or 38/720 reloads for airstarts?

Posted: Thu Sep 06, 2018 4:39 pm
by Kryten
IMHO, Blue Thunder propellant is the easiest to light.
Old White Lightning can be reluctant

Re: Which AT 38/360 or 38/720 reloads for airstarts?

Posted: Thu Mar 07, 2019 8:00 am
by Lamp
I would go with a CTI in the sustainer, the pyrodex slug in the top grain really makes them easy to light. If you really want to use an AT, as Kryten suggests, a Blur Thunder motor would be my choice...

Not that I have much experience with staging...I have only ever built and flown one! :wink:

Re: Which AT 38/360 or 38/720 reloads for airstarts?

Posted: Fri Mar 22, 2019 7:08 pm
by matthew
Lamp wrote:I would go with a CTI in the sustainer, the pyrodex slug in the top grain really makes them easy to light. If you really want to use an AT, as Kryten suggests, a Blur Thunder motor would be my choice...


I really need to recheck what motors I ordered, but I'm fairly certain it will be a CTI in the sustainer.

Not that I have much experience with staging...I have only ever built and flown one! :wink:


Yeah, hard to fly it twice when half of it is MIA. I gather you never saw it again? Amazing flight, it was, too. :shock:

Re: Which AT 38/360 or 38/720 reloads for airstarts?

Posted: Sun Mar 24, 2019 1:25 pm
by Lamp
Yeah, I never got the sustainer back, I suspect it ended up in the dam...and yes it is true that it is hard to fly it again like that Matthew. :wink:

One of these days I'll re-build the sustainer...but I'm in no hurry. 8)