RRC2L for sustainer separation charge?

[StreuB1]

I posted this a few days ago in the staging sub-forum but haven't received any replies so thought reposting in the HPR section might get some traction.

I am about half way done building my Madcow Nike Apache I bought during the Black Friday sale in 2018....better late than never, right?

I am following CJ's build pretty much line for line but with a few small changes.

I would rather not stuff an RRC3 in the interstage just to do apogee and separation charge (main via Jolly Rancher). So I was thinking about using my RRC2L since you can reprogram the main deployment channel to act as an aux channel like on the RRC3.

My question, has anyone else done this? Anything I should look out for or be aware of?

This will be my first 2 stage with electronic staging so I want to make sure I think things through and ask all the questions.

Sustainer will be controlled entirely by an RRC3; apogee, main, sustainer ignition.

First flight will likely be very tame with an I599N in the booster and a G125T in the sustainer. Its a pretty hefty rocket so I don't expect any records, nor do I want any. Fast, low, and successful is all I am looking for.

Thank you in advance!

 

[Titan II]

Here is another option. I typically fire the separation charge simultaneous with the sustainer ignition. Both are fired from the aux channel of an RRC3 in the sustainer. I use an RRC2 in the booster for its recovery. The booster hangs with the sustainer for a little extra time reducing altitude, but that is not an issue to me. Works 100% of the time.

Regarding your question. I have several RRC2s, but not the new one and have not looked at its features. However, if it can be programmed as a timer, I do not see any reason it would not work.

Some here say two stage is hard. It is not hard whatsoever. Just be meticulous planning the flight and in programming the altimeters.

Two stage is fun....enjoy.

 

[wonderboy]

Sorry I can't actually answer your question as I've never done what you're doing before. However, I am interested in hearing the solution. I have an RRC2L as well. Based on my reading of the manual, it seems you'll use:

OCS Trigger Event = 1 ( Launch - Altitude > Arming Altitude and unit has not reached apogee )
OCS Ops = 2 (Event -> Timer - Main is activated via trigger and timer )

There is another option to compare the altitude with a one-shot compare (OCS Ops = 4) where it does a final check that your altitude is either < or > a designated value. I guess you'd use this if you didn't want to change the arming altitude. I'd guess you'd want to make sure you are > a certain altitude threshold (determined by sims) which would indicate you have a good launch/boost phase.

What are your thoughts on settings?