Sunday, February 3, 2013

Plaster City launch report for Feb/2013

Reporting the day after the launch?  Unheard of yet so very true!  Here are all my select photos from yesterday.  Oh and it's [not at all] hilarious now but I managed to forget my motor casings, bottled water, and K1999 liner yesterday!  Packing FAIL. Rectification required.
     Despite the weather predictions... we again enjoyed windless flying conditions in the Imperial Desert with clouds materializing only later in the day.  I seek to fly as many motors of interest in this life and yesterday ticked another off my bucket list with a CTI 614I100 Red Thunder long-burn in the reliable Polecat Aerospace 4" V2.  I forewent video so here's the record of photons sequestered:

You'll note that the liner started to burn through but my new Pro54 3G casing remained unscathed. Here's the Altimeter Two data:
Peak Altitude (baro)4,491'
Peak Velocity301 MPH
Motor Burn Time4.0s (2s short!)
Peak Acceleration16.5 gees
Average Acceleration3.5 gees
Coast Time14.8s (long by 3s)
Apogee-to-Eject-11.2 s (?)
Peak Altitude (accel)2,642' (?)
Descent rate7 MPH
Flight Duration262.6s
Created with the HTML Table Generator

Next up was my scratch-built Em-Sem-Fity on an AT 2540K1999 Warp9 reload.  Jack kindly loaned a casing to me yet there's still something missing... oh yeah it's the friggin' phenolic liner resting comfortably in my downstairs closet!  I remedied this buy buying an AT K458 White Lightning reload, used that liner yesterday, and will use the K1999 liner next time.  Here I'm about to shot-put .. I mean load up the "coffee can" motor:

The cloud cover had rolled in by the time I loaded up and then I had a slew of igniter problems but it was all worth it with this stunning, mach diamond-laden ascent!:

There was zero wind so I popped a 9' main at apogee to reduce my prep time and we landed about 1/4 mile west:

I think I figured out some of the igniter problems:
1) The first CTI dipped e-match partially burned and failed to ignite the motor.
2) Then I switched to one of my personally dipped igniters.  Despite their high historic reliability this, too, failed.  I'm guessing the pyrogen wires were shorted internally so it showed continuity but never burned.  We also had a strange problem where I showed continuity at the pad box but not at the launcher box.
3) In the end I hooked up my Rockontroller and, with Jack's help, selected a third igniter and got that AP burnin'.
Thanks to Dave and Jack for working through those issues over a half hour with me.  And thanks again to Jack for the casing loaner! RockSim 9 predicted 7,379 and I thought the program was high :). The ARTS2 (7,056') and the Raven2 (7,093') averaged 7,075' so the simulation hadn't been as baked as I suspected. Here are the details:

Raven2: graph, tabular
ARTS2: graph, tabular, motor performance (corrected liftoff weight yields 2562L1601), CD (corrected as well)

The peak acceleration was only about 25 gees (nowhere near the 50g accelerometer max) so I'm really not sure what's up with the motor performance data [Now I am.  The liftoff weight stuck in kg rather than lbs. so I've corrected that above].

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