Failed Level 2 attempt: but many things learned

[rAiN_Twist]

For clarity, I use sheets of Kevlar similar to the way nomex is used. The sheets are attached to the shock cord and re-used for multiple flights. I am not using shredded Kevlar.

That’s an interesting idea. People around where I launch just throw shredded Kevlar in a tube, lol.

 

[dshmel]

8 years ago I purchased 23 sheets of Kevlar for $0.90 a sheet from Commonwealth Rocketry. I don't know if they are still in business. You can get a dozen or so uses out of a sheet before it starts to burn through. It is not as robust as nomex, but it is very thin and pliable. It takes up much less volume.

 

[JLebow]

Because this wasn't set up as a dd, I was using motor ejection with a backup charge set at 500'. We could hear the event at apogee even though we couldn't see it.

I agree with timbucktoo that the motor eject occurs at 13.5 seconds, still coasting up quite fast (>100 MPH).

But another thing you might want to check before your next flight. You said a backup charge was set for 500 ft. The log file shows that the drogue charge is not connected at all (0 V the entire flight) and the main charge went off just after the motor deploy, but well before apogee:


Maybe the tilt sensor triggered the apogee charge. It starts to show tilt at 13.6 seconds:

Either way, it doesn't look like it was set as a backup.

 

[PT3]

I agree with timbucktoo that the motor eject occurs at 13.5 seconds, still coasting up quite fast (>100 MPH).

But another thing you might want to check before your next flight. You said a backup charge was set for 500 ft. The log file shows that the drogue charge is not connected at all (0 V the entire flight) and the main charge went off just after the motor deploy, but well before apogee:
View attachment 357335

Maybe the tilt sensor triggered the apogee charge. It starts to show tilt at 13.6 seconds:
View attachment 357333
Either way, it doesn't look like it was set as a backup.

There was no voltage on the drogue channel because there was no drogue charge. The sole back up charge was set to go at 500’ in case the main (only) chute didn’t fully eject. It didn’t go off at all because the shock of the chute shredding dislodged one of the leads.

Watching the replay of flight, the voltage on the main (500’) charge goes to zero right after the motor eject pushes the main out at speed. That and the unexploded bp capsule recovered with the airframe leads me to believe that it didn’t ignite.

 

[JLebow]

Watching the replay of flight, the voltage on the main (500’) charge goes to zero right after the motor eject pushes the main out at speed. That and the unexploded bp capsule recovered with the airframe leads me to believe that it didn’t ignite.

Yeah, those are very good clues. I get nearly as much enjoyment out of looking at the log files as I do actually flying. Nearly...

Best of luck on your next attempt.

 

[PT3]

Yeah, those are very good clues. I get nearly as much enjoyment out of looking at the log files as I do actually flying. Nearly...

Best of luck on your next attempt.

I do too, though I don’t get nearly as much out of them as many of you all do. It’s an unorthodox set up I realize, but it seemed like a good idea at the time. It might even have been, until the early eject.

Live to fly another day. Amazingly the rocket suffered fairly light damage all things considered.

 

[cwbullet]

Interesting analysis. I would make a checklist for the next launch to make sure you check all these items. Even if it did not happen this time, if you check it next time, you will enhance your rate of success.

 

[PT3]

Interesting analysis. I would make a checklist for the next launch to make sure you check all these items. Even if it did not happen this time, if you check it next time, you will enhance your rate of success.

Not a bad idea.

 

[OverTheTop]

It’s an unorthodox set up I realize, but it seemed like a good idea at the time.

Unorthodox doesn't make it wrong. Think it through. If it will work successfully (particularly off-nominal) then fly it and learn. Some people might say "That won't work" but if you think it through and can see no hurdles (and talk other people through it) give it a go. Thinking differently is an underappreciated art.