Electronics Bay Alts...Which should I use?

[DAllen]

I'm having a dilemma. I have 3 alts and want to use a max of 2. The RRC3 is about 3 years old with 3 or 4 flights on it. The Adept22 and RRC2 are probably around 10 years old or older and many more flights on them. All seem pretty reliable. In any case I am definitely using the RRC3. I don't plan on spanking this rocket hard so maybe like a max of 4-6k and keep is subsonic. With a rocket this size is do others just fly a single alt or does the collective hive-mind insist on 2 alts? Just curious others thoughts here...

 

[Titan II]

If they fit, always two.

 

[Buckeye]

always one.

 

[rfjustin]

Just the RRC3, but parallel wire (2) e-matches to each charge.

My .02

 

[FMarvinS]

Dave,

Although the Adept 22 is a very capable altimeter, it is plagued by malfunctioning when GPS receiver/transmitter units are on board. Thus, if planning to use a GPS tracker, avoid the Adept 22.

Fred, L2
ICBM-S.C.
KG4YGP

 

[DAllen]

Dave,

Although the Adept 22 is a very capable altimeter, it is plagued by malfunctioning when GPS receiver/transmitter units are on board. Thus, if planning to use a GPS tracker, avoid the Adept 22.

Fred, L2
ICBM-S.C.
KG4YGP

This is interesting. Would a Marco Polo transmitter have a similar effect? If so, that would explain some oddities that happened in one of my flights this past winter.

 

[ksaves2]

Dave,

Although the Adept 22 is a very capable altimeter, it is plagued by malfunctioning when GPS receiver/transmitter units are on board. Thus, if planning to use a GPS tracker, avoid the Adept 22.

Fred, L2
ICBM-S.C.
KG4YGP

Ahhhhh yes,

I had a 150Mw tracker dork a deployment altimeter on the pad and one in flight before I "found out" the phenomena. Started ground testing flight combinations then. I tested the Adept 22 years ago with GPS trackers on the ground and the Adept shut down every time, P6K blew charges on ascent.
Always ground test a tracker/altimeter combination on the ground with bare ematches attached unless you know someone has already done the testing with the same exact hardware one plans to fly with. Easy to do. Setup the rocket as if to launch, turn everything on and let it sit again with contained bare ematches (no BP). If the charges don't blow or the altimeter doesn't "lockup or shutdown" after a half hour to an hour test, one is good to fly. Least likely to have an anomaly on ascent. Kurt

 

[Titan II]

...but parallel wire (2) e-matches to each charge.

Excellent suggestion. I do the same...along with the two altimeters.

 

[Voyager1]

Just the RRC3, but parallel wire (2) e-matches to each charge.

My .02

To the best of my knowledge I’ve never had an ematch failure, and I use 4 each flight for redundant dual deploy with two altimeters. I can certainly see the benefit of parallel ematches on a single altimeter if your ematches are unreliable. However, I would make sure that your altimeter outputs are happy with the increased current. In the case of the RRC3 and RRC2, their outputs are rated for 3A.

To address Dave’s query, in one of my avbays I use an RRC3 and an RRC2L. I’m very pleased with that combo and I can use the LCD module to configure, check the settings and flight data of both altimeters. Additionally, as recommended by Missile Works, in this case I use the 9V batteries, not LiPos, with these altimeters.