Sunday, June 14, 2015

RocStock 41: Punisher got punished, M3100s kick ass!

For me it was drag race central at RocStock 41 at Lucerne Dry Lake. David Reese, Mr. Wildman West, organized an amazing deal for a Punisher kit, 2372K1440 White Thunder reload, Pro54/6G casing, and 54mm closure.  It was a bit breezy when arrived at ~8:15AM on Saturday morning only to learn that I was supposed to be ready to fly by 8:30AM!!  I managed to pull everything together for the Punisher drag race by 8:45 and mine was the sixth rocket on the table for weigh-in/check-in so I wasn't the last.  Of the ten planned flyers only nine checked in and the following video summarizes the results (along with the M3100 drag race later in the day):

Not that I'm being cross-examined but I certify that I did nothing special to my K1440 reload.  I added a bit of SuperLube to the threaded portion of the brand new Pro54/6G casing before inserting the reload, left the delay intact as an apogee backup, and used the stock igniter from CTI.  I'm guessing my two counterparts who CATO'd would say the same so one theory was that the propellant might not have cured fully in this batch of reloads.  This, in combination with the excessive heat and perhaps humidity, might have played a role in the 33.3% failure rate. Here's a link to an amazing liftoff shot from "Apex Horizon" on Flickr and mine is the center CATO (thanks to Mark Treseder for forwarding but this photographer has sharing turned off so I can't show it inline with my blog). The nosecone, electronics bay, and most of the recovery harnesses survived but here's what's left of my booster (I piled the other parts together atop the parachute):
Punisher remnants after K1440 CATO. :(
Here are the Raven3's graph and tabular data from the brief flight. Note that the accelerometer maxed out at 315 Gees so I'll need to check with Featherweight Altimeters on that before flying it again.  In the image above one fin is stuck in the ground and the other two presumably blew out as I assume the casing wall failed and overpressure the booster.  This fiery activity also likely ignited the 2g bag of black powder and popped the three shear pins securing the electronics bay/nosecone thus saving those costly components.  The Raven 3/250G also seems to have popped the nosecone after apogee, such as it was, thus releasing the parachute and further reducing impact damage.  The booster was still smoking and, when I picked it up, flames arose.  I then buried it in the lakebed clay for a minute or so and the flames extinguished.  I returned the booster to David for failure analysis, unscrewed and kept the otherwise intact enclosure, and David immediately replaced the casing and reload.  I'm hoping that a few months of extra curing time along with a plan to fly in cooler conditions will render this second K1440 viable.  I plan to buy parts for another Punisher booster as this strikes me as a phenomenally volumetrically efficient design.
     I was a bit shaken at this point but David verified he still wanted to fly our planned DarkStar Extreme/6118M3100 White Thunder drag race if I did. Since I'd already bonded the grains into the liner I really didn't want to leave that loaded up in my closet and decided to proceed as planned.  As always it took awhile to disassemble the CD3 system used in the Punisher and rewire it, along with my second CD3, into the trusty DarkStar Extreme but I was ready at about 1PM(?).  Kurt Gugisberg was our RSO and chortled as David and I approached.  I asked what he wanted to know about this juggernaut of a rocket and he replied "Ummm... what color is your parachute?" and, while I answered factually, I later suspected he was referring to the business book of the same title.  :)  David and I set up on pads 41 and 42 and I'm very pleased that we both took off like bats out of hell and recovered our rockets safely.  David noted that he heard applause after the race and both of us could clearly see our rockets from apogee all the way down.  Here are the GPS plots from Google Earth as well as a recovery shot showing my landing less than 1/3rd of a mile away -- a rarity for any flight of mine:
M3100 GPS plot facing due North
DS Extreme recovery after successful M3100 drag race with David Reese.
Here are the M3100 altitude summaries:
Velocity / axial acceleration peaks:
  • Raven2: 1121 MPH / 54 Gees
  • ARTS2: 1195 MPH / 38 Gees
And here are the Motor Performance (6451M3506) and Coefficient of Drag plots from the ARTS2.  Thanks to all my fellow drag racers and I look forward to future challenges!

Friday, June 12, 2015

Dude built a Punisher!

BAM!! Finish ya after the K1440 drag race tomorrow?
And here's a very aggressive 12g CO2 test for the nose cone: