Hello List-
I flew a rocket a few days ago in search of the J altitude record. The rocket teleported off the pad & quickly got to over 3000ft/s. Very quickly after that, the telemetry reported the drogue firing (at around 10k ft) and then the rocket peaked a few thousand feet later. The accel data show a deceleration momentarily maxing out the G meter. So, about a 100G accel followed by a 100G decel. Ouch.
I’m still trying to figure out exactly what happened. I think the motor made it all the way through burnout, then some “event” happened. The rocket and all the recovery gear are still in great shape, so it’s tough to point a finger at anything from just looking at the rocket. Can I please get some thoughts on what happened based on the data? Is the “drogue” callout on the flight replay matched to the TeleMetrum firing the drogue? If so, why did it fire it so early? I’m definitely not ruling out the rocket tumbling, but the motor exhaust looked straight until we couldn’t see it any more.
FWIW, this was the first flight on a new TeleMetrum. The telemetry page showed that v1.8.5 is loaded. I’ve flown an EasyMini before to about Mach 2, but not a TeleMetrum and not anything approaching Mach 3. This was the maiden flight on this rocket. The chute was in the nosecone & that’s the only thing that gets ejected (single chute at apogee was the plan). My drag & decel calcs show that the nosecone should have plenty force holding in place throughout the flight. It was a fairly tight fit and held on by a single 0.060” styrene rod as a shear pin. I’m not ruling out a drag separation either.
Here’s a Dropbox link for the data file:
https://www.dropbox.com/s/fomf36le9yaeec2/2018-05-28-serial-4989-flight-000… <https://www.dropbox.com/s/fomf36le9yaeec2/2018-05-28-serial-4989-flight-000…> (just click the 3 dots on the top right corner of the screen & select download - you don’t need to be a Dropbox user)
Thanks!
-Bryan
I'm using a Altus Telemega and saw you can set the Pyro Firing Times. Is
there a recommended duration when firing e-matches with a 1S LiPo (800Mah),
does the recommendation change if I add a 2S as a separate Pyro battery?
Gordon Bain
Pflugerville, TX
