Sunday, January 27, 2013

Plaster City Jan. 2013 Launch Report

Executive summary for San Diego's first launch of 2013:
  • Brilliant weather!
  • Unparalleled assistance!
  • Great launch success!
  • Liftoff photos and onboard video?  Not so much.
First off I'd like to thank Darrel, KO, Jason, and Jonathan for all their help that day.  We've been really lucky at Plaster City in recent months and the myriad wind deities seem appeased; it really is amazing how they play together despite disparate origins.
     I actually painted a fiberglass rocket!  Rattle-can painting has simply sucked ever since really robust surfactants have been phased out.  I'm all for environmental protection but will challenge the paint industry to synthesize equivalent substitutes that actually work well!  I think I found a reasonably good substitute admittedly at a greater cost: Krylon Fusion.  It's designed to adhere to low surface energy plastics seems to work similarly to older paints as I recall.  Here's my DarkStar Lite all prepped and pretty on a CTI 382I243 White:

The turbo ascent and the long telephoto lens conspired to prevent a liftoff shot but KO did catch my aft rail guide flinging into the air and that's cool:

I had also purchased a Jolly Logic Altimeter Two and this was its first flight.  While there's no data download/graphing capability I must opine that the list of flight attributes impresses:

Peak Altitude (baro)5,370'
Peak Velocity649 MPH
Motor Burn Time1.6s
Peak Acceleration22.9 gees
Average Acceleration18.3 gees
Coast Time12.3s
Apogee-to-Eject-0.2 s
Peak Altitude (accel)5,217'
Flight Duration226.6s
Created with the HTML Table Generator

Note!: One needs to clear the data after each flight as these altimeters do not auto-reset.  I learned this lesson later that day...
     My second flight took a super long time to prep because, well, I'm me.  I had finally finished building what I call the DarkStar Extreme 'Heavy Duty' which is a misnomer because it's actually of nominal strength.  You may recall that I was sent the wrong fins on my original DarkStar so this second booster build gets me back into the nominally heavy duty range.  Darrel not only help me set up the flight but also lugged the beast out there on his own and thanks again!:

I've been wanting to fly the CTI 6162M1675 Pink reload for over a year now but my previous "lite duty" booster seemed on the edge of strength with the CTI 4828L1410 Skidmark flown last year.  The night before I also had the idea to launch another fast rocket with onboard video just as the M1675 was pressuring up to hopefully produce some amazing ascent video from two perspectives.  I chose my trusty Bullet on a CTI 419I800 Vmax reload for the chase-cam video.
     The M1675 pressured perfectly, the I800 ignited instantly and lead by the amount I'd imagined, and both flew and recovered perfectly!  Here's a shot of the M1675 pressuring-up and that puff on the right shows the I800 ignition timing:

Here's a closer crop of the beautiful, nebula-like, red/purple startup fireball:

Unfortunately the M1675 onboard video was corrupt after downloading.  I'm trying to salvage it and will post any recovered action in the future.  The I800 video was completely absent!  I know I started the camera correctly but there wasn't even a corrupt fragment to try to recover.  And, as I'd mentioned, I failed to reset the Altimeter Two and have no I800 data.  Wow.  Now back to good news: the Beeline GPS worked flawlessly this time both for recovery and data plotting! (looking West, click for 2x larger version)

I had perfect satellite lock the whole time and saw a peak altitude of 13,077' on the Yaesu radio display.  The peak altitude in the human-readable portion of the .kml file is 4,317m or 14,160'.  The average of the ARTS2 (13,621') and Raven3 (13,898') is 13,760' so that's only 2.8% lower than the GPS peak.  For the data retentive (corrected links thanks to Darrel):

Raven3 (250G model): graph, tabular
ARTS2: graph, tabular, motor performance (5727M1786), coefficient of drag

Based on this success I've queued up an 6800M3700 White Thunder soon but think I'll fly a 'mellow' 7388M2045 Blue Streak in February first.  And with that entry I'm caught up for the first time in a year.  Cheers to continued success and viable onboard video!

Tuesday, January 22, 2013

Plaster City December 2012 launch report

I'm clearly on a blog roll now...

My goal for December was fun and easy flying so I packed sparsely planning for no dual deploy, no onboard vid, and no GPS headaches.  I sought leisure via simple motor ejection and perhaps a Jolly Logic Altimeter One thrown in for good [barometric] measure.
     Jack had the new CTI Pro38 654J316 Pink reload in stock so I snapped one up and threw it into my trusty Bullet for its trillionth flight (click to enlarge):
The neck-snapping ascent rocked and I'm a bigger than of pink than ever.  Real men fly pink.  The Jolly Logic reported 4,075' and there was much rejoicing.
     I also had this CTI Pro54 1990K490 Green^3 [figuratively] burning a hole in my closet and it seemed perfect for my 5.5" Polecat Aerospace Jayhawk that I hadn't flown for some time.  The pressure-up was a bit slow but I never get tired of that stunning, barium-free green flame (click to enlarge)
The uppage was way cool until 'round about Max Q when it looked as if a canard fin had ripped off.   Hmmm I'd built this thing quite robustly but it's hard to reinforce those big, potentially floppy wings. In any event the parachute appeared to eject right at apogee but wasn't fully inflating.  Despite taking my own advice and repacking my 'chute immediately before flight, unfortunately, the 12' diameter behemoth fluttered ever groundward without ever fully inflating. I very close to touchdown and could see all the wings/canards had survived the flight. The as the Jayhawk impacted the ground one corner of one canard cracked on impact.  So yet another stooped fouled 'chute had damaged yet another prized rocket:

The Jolly Logic altimeter reported 4,711' but I wasn't sure if I could fix that fin.  Jack thought he might have a spare at home but I decided that a) I don't really want to fly rockets that flap about at Max Q and b) I don't maintain a rocket museum at my house for show-rockets.  In the end I salvaged what I could and dumped this orange rocket in the trash.  Oh and about that time I noticed that a hole had been poked in the nosecone as well so double-hmph.

Saturday, January 19, 2013

Plaster Blaster 2012 launch report

PB2012 was a great launch for me featuring two days of amazing weather, no camping required as I've discovered El Centro hotels,  and I was very pleased with the fourth flight of my scratch-built Em-Sem-Fity minimum diameter 98mm rocket.
     Frank Hermes, Mark Clauson, and I entered this year's fourth and likely final M-Moonburner drag race.  The new BLM requirement that drag race flyers must ensure a recovery radius of 25% of the expected altitude from the nearest public features like roads and high-power wires was kind of a bummer.  This pushed our launch pads to the north edge of our 'bowl' and, earlier, we had set them up in patches of dirt distant from flammable brush.  After we'd prepped it was kind of Mark and Craig Clauson to drive all of us out to those launch pads where we set up quite quickly.
     I wasn't able to take any liftoff photos but can at least move the onboard video to this post (same as you might have seen earlier but why not watch it again? :)

     Frank really wanted to win again this year and I was with him the night before when he purchased plastic wrap and cellophane tape to seal up his 10g thermite bundle for ignition.  Jack Garibaldi offered the use of his super high current launcher and it did its job well. Frank's M750 of course pressured up instantly, followed by Mark's trusty M650 setup, and then my lagging ass standard igniter pressured up the M750 for third place.  All three rockets flew somewhat neatly apart from each other atop those fun long-burn M motors.  Note to self: I really want to start using more thermite in 2013.
     All three of used Beeline GPS units for tracking this time. Mark was having issues with his proprietary GPS setup so Frank loaned a spare Beeline to him.  I was using my brand new transmitter of the latest design and I was confident that it should work.  As always I threw in a Comm-Spec tracker as a reliable backup.  Strangely we all had intermittent issues with maintaining satellite lock on the ground. Likely causes might have included general satellite interference or possibly military jamming although that remains speculation on our part.
     After liftoff none of us received any GPS updates but my Comm-Spec receiver continuously produced a healthy blip.  Its signal conveniently increases in strength/volume at apogee because the transmitter moves outside the carbon fiber body tube.  So, even though I can no longer see the rocket, I have an audible indication of apogee separation.  Interestingly, and highly abnormally, my ~20,000' flight landed inside the bowl!!  I was really psyched on this and we could see the main pop at 800' as expected.  My elation quickly subsided, however, as my buddies Frank and Mark still lacked any trackable signal as I was gathering up my bundle.  We searched for some time but later learned that Frank's rocket had come in ballistic leaving little of salvageable value.  Mark was never able to find his rocket and it remains missing to this day.  Sorry fellas but it's happened to all of us.  :(
     Back to my new Beeline GPS... the downloaded .kml file produced a beautiful, firework-like burst of points all very near the ground:

WTF??  While no altitude data point in the file gets anywhere near 20k I can say that none of data rows seems askew as with my older unit (no negative latitudes for instance).  From this January's launch I'll foreshadow that the GPS unit is ignoring the 'convert meters to feet' flag in the programming software so the peak value in this data set would seem to be 178m or 583'.  I think this looks close to what I'm seeing in the plot above.  I'll attribute this data failure to GPS satellite or scrambling issues as the unit now appears to be working correctly so... YAY!!  Finally.
     As for altimeter data the Raven2 reports 19,465' AGL and the ARTS2 looks good at 19,561AGL (0.4% delta).  It appears that the ARTS2 motor performance data is whacked at 6964M1004 with a 6.98 second burn time.  From the onboard video the burn time is roughly 14.3 seconds so let's assume the ARTS2's motor performance estimate is null and void.  Here's the data for the numerically retentive:

Raven2: Graph, Tabular
ARTS2: Graph, Tabular, Motor Performance (WRONG), Coefficient of Drag (questionable)

Frank was understandably bummed at his loss and was talking of retiring from rocketry before leaving the launch.  Since then he says he's exited his slump and wants to build a nifty clustered/staged rocket using his Tilt-O-Meter2 at some point soon.  I'm glad he's back on the horse and hope that Mark's recovering from his loss as well.  I'm not sure what we'll do at this year's Plaster Blaster but I'd like to avoid the BLM constraint on launch distance so we'll see.
     We flew a mini drag race on Sunday limited to G motors.  I chose the CTI 110G250 and it was sorta fast.  Victory at last!!

Monday, January 7, 2013

BALLS 21 does not equal gonads now legally authorized to consume ethanol... offers far more to the cutting-edge rocketry community.  Let's start with the video fragments of my first N-motor flight (720p/full-screen always work best):

I'm quite happy with the video I was able to salvage but I'll leap to the executive summary:

What worked:
  • A mostly cop-free 11-hour drive from Oceanside, CA to Black Rock, NV and back.
  • The brilliant foresight and planning of my fellow San Diego fliers.  We had an amazing compound nearly dead-center on the range.  Thanks, compadres!
  • A beautiful CTI 14272N1975 Green^3 reload (thanks to Kris' friend Molly for shooting):
  • Perfect flying conditions on the days I attended.
  • Unparalleled and proactive mutual respect from all fliers in attendance.  I was somewhat awed by the inverse attitude/magnitude relationship!  This is a very cool community.
  • Mark and Craig Clauson's incredible rocket hunting ability! Thank you both once again.
  • Frank Hermes' amazing 2-stage flight featuring the Tilt-O-Meter 2.
  • Everything else except...
What didn't:
  • Not repacking my main 'chute!!!!!!!!!!  For the first time EVER by the way.  This seemingly minor error on my part converted my 'simple, fun first N motor flight' into many, many small but costly repairs and replacements.  Repack your recovery system every time por favor.
  • Camping.  I suck at it and I'm at peace with that.  The first night was unbelievably cold and the second night was warmer yet provided just enough wind and flappy tent top that I attained approximately zero REM sleep.
  • My older Beeline GPS.  I was locked on the ground but never received any position or altitude data and my Google Earth plot was a complete GP[mes]S once again.  Yes four data points points can form a trapezoid but... ummm... ?:
  • Friggin' tattle tale Nevada drivers and innumerable 65-55-45-35-25 zones on state highways 50 and 447.  Can they be serious?  My jaw remains agape that some kindergarten-level utility truck driver in Fernley radioed in to the police that he thought I was following too closely.  Well fuck that guy 'cause he apparently needs to create some genuine drama in his life as I pay painful amounts of attention behind the wheel.  Bonus: the cop was the coolest I've met in my life.  He checked my docs, let me go without even a warning, and provided driving advice to Black Rock.  Now that's what I'm talkin' 'bout!!
  • Sadness that I just typed way more negative words than positive because...  
This events rocks and experienced fliers simply need to ditch their families for a couple of days and participate at least once in their lives.
     So the up part was amazing, the down part was invisible, both GPS and Comm-Spec tracking failed, and the formidable Mark & Craig Clauson returned my rocket.  Upon first inspection I was very happy but, over the coming days, I slowly realized the damage that a fouled main can do.  I won't belabor it but I suspect my ARTS2 was concussed so I'll estimate my final peak barometric altitude at the Raven 2's ~17,963'.  For my data-nerd-bretheren here are the various outputs:

ARTS2 + grain of NaCl: graph, tabular, motor performance, coefficient of drag
Raven 2: graph, tabular

I might append more later but, in summary, repack that main, drive as slowly as humanly possible in NV, and be sure to use your CB to narc on my CaliForNyAy drivin' ways.  Thanks for reading and exceed all expectations of yourself.