Adapting an Estes Comanche-3

I'm new to this forum, returning to MR after several years absence. I'm presently finishing a Comanche-3, looking to change the engine configuration. I've flown this model many times in the past... twice turning it into a 4-stage missile (using D12-0's for the intitial two stages...) I'm good at enhancing the body/fins for launch integrity. My question: can I use BP D12-0's for boosting 1&2, and then an E-12-4 for the top stage?

The only issue would be if the weight of the motors moved the center of gravity too far back to be stable. But the Comanche 3 is pretty long, so I bet that's not a problem.

And then there's the issue of ever finding it again.....

Thanks for such a quick reply! I will check the stability aspect, but as to not finding it again, well I've been down that road a few times before

I built a modified Comanche to take E12-0's to an E12-6. Simmed to 4500 but only got 1800 due to weathercocking. Pays to make several of the 2nd stage as these can get lost with boosts like that. And on the finding side the Comanche is an excellent vehicle for the ET Mini GPS. Helps with the stability too.

thanks so much! Did you actually have to re-balance?

I'd use a longer delay for your 3rd stage E-12.

Well the mini gps is a bit of a rebalance act. Sounds like you might want to get a hold of Open Rocket or Rocksim and run some tests. They're very handy for this sort of stuff.
And
Yeah. (Me) Should have been an E12-8 but the 6 was all that was available at the time.(aerobill) Make yours an 8 as well. Less likelihood of a zipper.
Cheers

OK, over my head... What is a "zipper"?

When the shockcord rips through the airframe like a zipper, usually caused by too long or too short of a delay and the rocket is still moving too fast.

Beat me to it, Rich.
Ejection delay too short causing the recovery gear to be deployed while the craft is still cruising to apogee. Shroud lines or shock cord get ripped back tearing a "zipper" down the side of the rocket.
Can also be caused by having the delay too long.

OK, thanks!

I've built a couple to be all 24 mm mmt's. I used nose weight to compensate for the heavier second and third stage motors. D12 to D12 to E9. Unfortunately my third stage didn't light, so upper stage recovery was less than optimal...
Finding the second stage was pretty difficult too.
This was before the E12's came out. I started another to do this again and just stalled.