Anyone using an apogee delay of more than 2 seconds on the redundant altimeter?

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jahall4

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If so what is the reason? I'm seeing on the Stratologger it can be set as long as 5 seconds.
 
Eject a payload with first altimeter, then chute with delayed one.
Screwball rocket with varying pressure differentials.
 
If your primary drogue charge doesn't fire or doesn't break the shear pins, you're going to start falling pretty quickly. By that five seconds, you'll probably be going close to 100 ft/sec (not counting any horizontal velocity you may have had). A good drogue should be able to handle that, so can a premium main chute. Nevertheless, 2 seconds is probably a pretty good maximum for your backup drogue; the less stress you put on them, the better.

The Eggtimer and Quantum altimeters can go up to 9 seconds, but we generally don't recommend going that late for a backup drogue. Note that the Quantum can also optionally fire the main chute if it detects that you've fallen for a specified time at a specified velocity; we recomment 100 ft/sec for 1000 ms (one second). If you get there, your drogues have failed completely, so that "FailSafe" feature will prevent you from coming in ballistic.
 
Nevertheless, 2 seconds is probably a pretty good maximum for your backup drogue; the less stress you put on them, the better.

Thanks, That seems reasonable to me, but I thought I'd ask in case I'm overlooking something.
 
Payload deployments and hail mary charges, both of which are more common outside of sport flights.
 
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