Failed (sorta) Recovery

[Kruegon]

A couple of weekends ago, at the TRA with Phoenix Missile Works, I sent my Partizon up on a G77R. This was the same rocket I got my L1 cert on.

Beautiful flight. I know this wasn't an HPR motor, but I usually flew on them. I dropped down because of wind concerns.

The prep for my rockets usually starts the night before. Build my motor and double check it. I test continuity on my initiators and my e-matches. I check the wiring on the altimeter. I check the voltage on the battery. I test the altimeter for for startup and flight ready status. My shock cords, fins, body tubes, and nose cones are inspected. Then everything is packed away for the launch.

After my Partizon went up, it rolled over at apogee, and began to descend. And it kept descending. And it picked up speed as it came in ballistic. Then at 300', the preset main, the altimeter deployed my main. And she came on down in one piece.


But not one, undamaged piece. The shock cord zippered my payload tube the 10.5", and the edge was reinforced with a layer of BSI 30min epoxy. It zippered so hard, it ripped the a/v bay retention screws out of the threaded CA holes.





When I opened her up, the drogue charge had failed to fire. Continuity test showed good prior to launch. Continuity test of the match by terminal block on the altimeter was good. By lead wires was good. By bulkhead terminal block was good. By e-match was good.

All connections were visually checked before and during removal for stray shorted wires. The e-match was removed from the charge and test fired alone. It fired exactly as it should.

This is the third time this particular altimeter has had issues. On two previous occasions, it has fired both charges at apogee. This time it failed at apogee but fired the main on schedule. I'm going to discuss this with Perfectflite again. This HAS to be a faulty altimeter. Eight flights total with 3 mishaps. Luckily for me, every mishap has been witnessed by several observers so it's not just my own word.

Luckily she can be repaired. Just one tube and a coupler from Estes. Kinda glad I never took the time to paint her. Woulda been such a waste.

 

[djs]

I'm not familiar with the perfectflite altimeters- but could it be possible that it has a setting wrong? To not deploy the drogue or deploy it when the main comes out? Definitely however sounds like something that needs replacing.

Second question- is there a reason you didn't leave the G77R ejection charge in? was the delay too short for this?

 

[Kruegon]

I've been flying on DD for a while now. I've never used motor eject for backup. No matter now, the damage is done. I'm building my L2 rocket with redundant altimeters.

I'll be contacting Perfectflite in the next few days. One way or the other this altimeter has to go out of operation.

 

[JimJarvis50]

By bulkhead terminal block was good.

If this is a terminal block exposed to BP, then that's where I would place my bet.

You can check the apogee deployment on your altimeter using a vacuum cleaner to "fly" to 3K feet or so, and then an LED light or some other bulb across your ematch terminals. This is an easy way to verify the altimeter, both apogee and main channels.

Jim

 

[Bat-mite]

Yeah, I would want to test it a bunch of times, pulling at different speeds. You could use one of these. Also, I know the PerfectFlite guys will do a thorough test of it for you, and return it if it is okay, fix it if it isn't. But shipping is on you.

 

[Kruegon]

If this is a terminal block exposed to BP, then that's where I would place my bet.

You can check the apogee deployment on your altimeter using a vacuum cleaner to "fly" to 3K feet or so, and then an LED light or some other bulb across your ematch terminals. This is an easy way to verify the altimeter, both apogee and main channels.

Jim

I've vacuum tested it. I have two ways to pull a vacuum. It tests fine under controlled conditions. I'm beginning to wonder if it has something to do with speed. All the failures have happened in fast motors. Two were G77Rs and one was an I200W. Possible an issue with the baro sensor under fast vacuum conditions?

 

[djs]

I've vacuum tested it. I have two ways to pull a vacuum. It tests fine under controlled conditions. I'm beginning to wonder if it has something to do with speed. All the failures have happened in fast motors. Two were G77Rs and one was an I200W. Possible an issue with the baro sensor under fast vacuum conditions?

What do your vent holes look like on the av bay?

It could also be a loose connection that normally seems ok, but under the forces of the flight shakes loose just enough to kill the connection?

 

[Kruegon]

What do your vent holes look like on the av bay?

It could also be a loose connection that normally seems ok, but under the forces of the flight shakes loose just enough to kill the connection?

The vent hole is very clean. So far I've had both charges blow at apogee twice. Once in my Scion and once in my Argent. Then I had a failed drogue charge at apogee in my Partizon.

So it's the same altimeter in 3 different rockets and 3 different a/v bays.

Didn't mean for this to turn into an altimeter discussion. Was just posting the sadness of a loss and the reason it was lost to share the experience.

 

[djs]

Didn't mean for this to turn into an altimeter discussion.

No! we demand full accountability! what color of underwear were you wearing when you attached the fins? Boxers or briefs?

 

[rharshberger]

No! we demand full accountability! what color of underwear were you wearing when you attached the fins? Boxers or briefs?

TMI....

 

[djs]

TMI....

Clearly Kruegon had issues with "the laundry" coming out, so I think it's definitely a pertinent question.

 

[Kruegon]

No! we demand full accountability! what color of underwear were you wearing when you attached the fins? Boxers or briefs?

Purple briefs I'm sure. I mean, what else would you possibly wear when attaching fins? Tighty Whities? I think not!