Thursday, November 24, 2011

PB2k11: Third annual M Moonburner drag race details

After posting two foreshadowing images below I'm finally getting around to documenting our nifty drag race three weeks ago.  I had trouble editing the Flip Slide video in Final Cut Pro 7.03 for some reason so I threw this together in Final Cut Pro X:

[I'm not really a huge fan of that software yet as it seems to be half way between iMovie and v7.03 in capability.]  Three of us flew the CTI 7521M840 and Mark Clauson chose the AT M650.  A HUGE thanks to Joyce Chan who skillfully photographed our drag race and was kind enough to share her source files with me.  Please head over to her site for larger versions or to buy prints of these or any of her other awesome shots:
L-to-R: Art/Tom Just, Frank Hermes, yours truly, Mark Clauson

Mark smoked us all with his minimum diameter L3 vessel on the M650!

I was second off the pad, then Art, then Frank.  I honestly thought we M840 flyers would have had an ignition advantage because there's a 29mm propellant grain with an embedded pyrodex pellet at the top of the core.  That plus the insane 459 pounds of initial thrust has me scratching my head.  Perhaps Mark was using a special igniter but, whatever the reason, he won the liftoff cleanly.
     I again used my Beeline GPS module to track the rocket as it was well out of site.  I threw in the beacon as backup and thought I'd need if as my Yaesu radio didn't receive any distance data until about 20 seconds before the rocket landed.  Not sure what's up with that but, in the end, the Beeline did the job and the Google Earth data was robust as shown in the post below.

As a fun aside we all kicked in $20 and employed a scoring equation including liftoff rank, peak altitude, and distance from the pad (highest score takes all):

Mark won with the highest overall score so congrats again!  While Frank didn't win this year he was the only participant to incur zero damage after a clean recovery.  Mark hit a power line on the way down and burned a 1/2" hole through the airframe and aft motor closure.  Art's 1/4" Kevlar shock cord snapped but he got all the parts back.  Mine suffered a hard impact that ruined my motor retainer ring and it took hours to free my motor casing.  I was able to salvage it however and will replace the ring with 10-32 screws through the retainer side wall.  Here my altimeter data if you're interested:

ARTS2 - tabular data
ARTS2 - graphical data
ARTS2 - motor performance estimate (7521M840->7045M989)
ARTS2 - CD plot
Raven - tabular data
Raven - graphical data

Thanks to all who participated and I look forward to another fun drag race at PB2k12.

1 comment:

Anonymous said...

Wow! You guys are completely off the hook. M's!