Eggtimer Quark based chute tender

Charles_McG said:

Looking closely at the nichrome, it seems like it didn't heat up the way the bench tests do. They glow yellow-orange for a second and are rough and grey afterward. This one was black in the middle and silver on the ends. I think I'll have to pay more attention to cutting just 1" lengths AND making sure they are firmly tightened in the terminals.

Click to expand...

Just a thought, but could the wind blowing on the nichrome as the rocket free falls affect how it reacts to the voltage?

Mass flow might transfer enough heat - but that spot is kind of sheltered in the final setup. I really suspect bad connections at the wire terminals.

Are you sure there's enough amps going to the wire? What I mean is- maybe there's enough variability in the nichrome wire that "sometimes" it lights, and sometimes it doesn't?

There's enough. And Cris extended the Quark fire time from 1 sec to 2 sec for me. (And likely others).

What's made the difference in recent successful recoveries, I believe, is that I've started tugging on the nichrome after tightening the screw terminals. I find that it often takes 2-4 tries, for each terminal, for it to grip. It will read closed circuit/channel ready and the Quark will go to 'waiting for launch' mode when the nichrome can be pulled out with a fairly gentle pull. I -think- that loose connection won't pass enough current to melt the wire. When the connection is right, it not only melts the fishing line, it melts the nichrome.

What are you using for terminals? maybe they're flimsy and/or prone to corrosion?

Flimsy, I think.

I'm using National Instruments compact Fieldpoint DC power connectors. Like this one, but with 2 screws, rather than 4.

Try moving to euro terminal blocks?

Example picture?

These:

https://www.missileworks.com/store/#!/2-point-Euro-Style-Terminal-Block/p/33363809/category=5760489