Keep it simple is the rule. There is no way to know exactly when a rocket is going to hit apogee time-wise for use with a timer. If I understand you correctly, you're wanting a motor ejection for back up of the drogue/streamer, which makes the timer obsolete when you're guessing at the time to apogee. With a timer you still have a chance of a zipper if it catches enough air and doesn't eject close to apogee. As for actual recovery, many simply break apart the rocket at apogee with no streamer or drogue. The rocket just falls flat as it catches air. Drogues and streamers aren't necessary all the time and some will argue that it only can cause more problems using them as it can cause the chute to get tangled. Just a matter of preference.
Your best bet is to use a simple altimeter. The PML Co-Pilot was the first one I used, made by Missile Works, and had lots of flights with not a single problem. It's simple enough, three beeps tells you main and drogue are good to go. Plus, the mounting hardware designed to work with their kits takes a lot of the guessing out of the equation. They have really great directions.
Make sure you have 2-3 vents for your altimeter to adequate air, and drill one small hole in each of the other sections for pressure venting.
Electronics don't have to be difficult. You only have to select the altitude of the co-pilot with two switches on the unit and it is really that simple. Load in a couple Daveyfire N28-BR ematches into the ejection canisters, pull through, seal the holes the wires run through with plumbers putty, seat the ejection canisters in the holders, wire in each e-match to the appropriate terminal, power up to check continuity, when that's good to go, turn it off, load up with 1.5 grams BP for a 4" or 1 gram for a 3" rocket, fill extra area with a touch of cellulose, put on the caps, wire the switch wires to the terminal, screw the rocket together with the altimeter in, put it all together and take it out to the pad and rock and roll.
Another thought to keep it even more simple, don't even use a switch to turn it on. I used to use switches, but went to simply twisting wires together after I saw many, many people flying rockets of L impulse and up doing this. No need to worry if the switch will turn off or break a connection on lift off. Worked well for my level 3 too.
A RRC2 was my first altimeter and it has never failed. However the organic analog computer responsible for the installation of the RRC2 has failed to execute the proper program a couple times. Ground testing and check lists can help you from becoming the failure point. Gary Deaver
Amen! I've had my ALTS2 for years and it's been through it's share of crashes(the alt worked just fine, operator error) and it just keeps on ticking(beeping). It's tiny too and uses a cheap 12 volt battery. I sim my flights on WRASP and I swear the ALTS2 differs from WRASP with a minimal 3% difference. As a added note I've tried my damnest to set off the firing circuit by bliping the on/off switch; it will not go off! Wish I could say the same for my Olsen FCP/M2 unit :(
I've flown quite a few of the altimeters out there( Adept , Missile works , Cambridge , Olsen, R-DAS , ARTS & G-WIZ ) & must say the RRC2 is just as good as the ALTS2 if not better. To date I've flown 30+ altimeter controlled deployments & have had Adept screw up on me twice ( 4 if you count the battery falling out twice& ALTS2 battery died once ) ( ALTS 25 fired while arming 1 ) G-Wiz once ( fired while arming ) & Missile Works Zero times ( knock on the biggest Oak Tree East of the Mississippi ) The majority of my flights were on the ALTS2 10 to 12 flights & the Missile Works 10 to 15 & still counting...
I've dealt with ADEPT on a number of occasions & can't justify spending the extra $30.00 on poor customer service & a phantom warranty.
As for a timer: NOT the Way to Go. My R-DAS fired early because of it ( back up timer built into it ) It's a guess at best .
I have the RRC2 and love it. I did my "Level E Certification" last summer, with a Stretched PML Ariel and a RRC2 on a I284. It was sure strange to use a plugged closure! I used Robby's Rockets pre wired disposable charge holders. Both charges fired as I planned [Chuteless drogue at apogee and main at 800']. I suggest you ask around your local club for help with dual deployment. I can send you Rocksim file of the modular electronics bay that I use.
-- James Dean Cory, D.C. TRA: 07839 L2 NAR 75296 L2 email@example.com