Our pyro guy dissected it and determined that the pyrogen was too thin in one spot, so it didn't ignite all of it. Out of his batch of 10, he tested 6, flew his own rockets on 2, and lit the booster with 1. Figures the sustainer would be the one that failed.
Casey On Tue, Jun 30, 2015 at 11:13 AM Kurt <[email protected]> wrote: > Homemade igniter? If so it might have popped and fractured the nichrome > wire. > Was it ematch/pyrodex or a dipped ematch augmented pyrogen or did you have > sufficient battery juice to use a standard nichrome dipped pyrogen igniter. > Kurt > -------------------------------------------- > On Sun, 6/28/15, Casey Barker <[email protected]> wrote: > > Subject: [altusmetrum] Update and Questions about TeleMega on 100K Attempt > To: "Altus Metrum" <[email protected]> > Date: Sunday, June 28, 2015, 7:58 PM > > We launched a > two-stage flight last weekend attempting to break 100K > again. The sustainer ignitor failed (incomplete pyrogen > burn), but the recovery was mostly successful, and we'll > try again next month. > In the updated design, we've got one TeleMega > and one EasyMega each, for both booster and sustainer. All > four units worked great. Having a common programming > interface and terminal block across everything has really > simplified our lives! > We had a couple of questions arise out of the > flight. They're all about sustainer ignition. To be > clear, the TeleMega clearly fired it because the igniter was > partly burnt. I'm just trying to understand the data a > bit better. Here's the .eeprom file: > > https://drive.google.com/file/d/0Bw8Fmi_7rzqMVnBLN2pjZFloUDA/view?usp=sharing > 1) We used the tilt angle lockout on the > sustainer ignition. I can see this is the tilt relative to > the pad orientation immediately before liftoff > (ao_ground_roll/pitch/yaw). I see the derived > ao_sample_orient goes in the OTA telemetry, but not the > eeprom log, which instead gets the ground values stored in > the header along with raw r/p/y. Presumably, that's > enough data to reproduce the same math. Unfortunately, > I'm not good enough at java to discern how these get > plotted in the UI. When looking at the .eeprom graph, is the > "tilt angle" still the angle vs. pad orientation? > (Or is that a silly question, because the gyros only give > rates not absolutes?) > I'm interested because the tilt angle graph > seems to start at a flat, non-zero value, roughly 3.7. We > did launch at about 2 degrees off vertical to compensate for > wind, but I wouldn't expect that to show up in the plot > if it were relative to pad. > 2) We also set a time window of >17 seconds > and <19 seconds on the sustainer ignition. (Really, we > want it to fire at 17 seconds, but we learned last year that > we needed to close the window in the event the sustainer was > off-angle to prevent a misfire during recovery.) In the > eeprom file, the "Ignitor A" event shows up at > ~17.2 seconds. However the "Ignitor A Voltage" > shows a brief drop around 15.5 seconds, and no sign of a > drop at the actual event. The other ignitor voltage drops > line up with their events, or immediately after. It seems > strange that this one was over a second early. I can't > explain that... We know it burned. Did our wiring briefly > glitch right before? > Also, possibly a minor bug: I don't see the > ground r/p/y and aux ignitor voltages in the csv export. (I > should learn java...) > Casey > PS: I made the new avionics bays on a 3D > printer. The bay models themselves probably aren't > useful to others, but I do have basic solid-body STL models > of both computers for evaluating fit and screw posts. > I'll share those when I get a chance. > > -----Inline Attachment Follows----- > > _______________________________________________ > altusmetrum mailing list > [email protected] > http://lists.gag.com/mailman/listinfo/altusmetrum > > _______________________________________________ > altusmetrum mailing list > [email protected] > http://lists.gag.com/mailman/listinfo/altusmetrum >
_______________________________________________ altusmetrum mailing list [email protected] http://lists.gag.com/mailman/listinfo/altusmetrum
