Sunday, November 10, 2013

Plaster Blaster 2013 for the win!

What an amazing weekend with perfect weather and record attendance at Plaster Blaster!  I was grateful that my parents trekked from Cochise, AZ and they were the icing on the desert cake.  Let's jump right in shall we? (I recommend this full-browser 720p HD link for best results or lazily click below for a suboptimal experience :)

I love our digital age but, until yesterday, I hated even nonlinear video editing.  I thought I was better at the legacy Final Cut Pro 7 than I really was and it turns out, after 11 intensive hours of training and practice in its successor FCP X, that I now sort of know what I'm doing! The above video edit took only about an hour this morning including compression and upload and I especially love the frame-hold pauses in the retime segment.  Now onto the launch...
     Here are Roy and me after the load-up but before the 'misfire' cause by my failure to even hook up the leads AND not asking someone to push the button for me!  Duh.  I blame it on my lack of practice since May:

The CTI Pro75/6GXL 9977M2245 Imax is a new fave!  Damn that thing was aggressive:

Some observations:
  • For the first time all the photos, video, altimeter and GPS data turned out perfectly!  Hundredth time's the charm.
  • For the second flight in a row I'm getting about 0.75 seconds of pressure up time with this CuO/Mg thermite recipe.  I think I might use half an igniter cap next time and see if I can shorten that latency without risking overpressure.  Note the wicked smoke pattern as the M2245 fires up:
  • I think mach 1.7 (1,323MPH) is the greatest speed I've yet recorded.  In the video you probably noticed black bits of Gorilla Tape melting off after the speed of sound was passed.  Here's the result but the video still seems rock solid to me and the camera's fine:
  • Gerald Meux, Tripoli overachiever and super nice fella, kindly shared his full-res shots of the ascent (among many other shots of the weekend).  Who doesn't enjoy a nice rocket up-skirt?
  • Yay, drogue eject just before apogee!!  After last month's dreadful 5 second latency after apogee I contacted Adrian Adamson at Featherweight Altimeters.  He emphasized that everyone should be using barometric ejection at apogee on all Ravens.  I had been trying to soften the apogee forces by ejecting when the rocket passed below 20 ft/s but Adrian noted that I would have had to "game the system" and set the Raven 3 for less than 164 ft/s for that to work.  In any event I'm setting all my Ravens to baro at apogee and never looking back.
My recovery distance used to average a one mile radius.  That seems to have increased to 1.3 miles as that's the identical distance for two months now even with essentially zero wind:

Roy and I drove to the south edge of the wash (0.5) miles and I walked 0.8 miles there and 0.8 miles back.  I found her safe and sound lodged in a shrubbery:

Max altitude: altimeters = 19,357', altimeters + GPS = 19,705
Max velocity: 1,323 MPH
Max acceleration: 24.9 Gees

(ARTS2: graph, tabular, CD analysis, motor performance (9578M2661))
(Raven:  graph, tabular)
(GPS: ground-level, eye-level with apogee)

On Friday I also flew a CTI 567I125 White in my 2.6" Madcow Nike Smoke.  No photos or data here but that was a fine flight!  Finally I had planned to fly the freshly painted and stickered Der Red Mix mark II (below) but simply ran out of time.  By the time Roy and I got back from retrieving the above flight it was 3PM and I was spent.  DRM II will be my priority at Plaster in December and I hope to get her (him?) flown.
     Congratulations to: -Frank Hermes for his mostly successful, highly complex clustered/staged flight.  -Darrel Kelley for blowing away the President's Challenge with 23,232'.  -Jonathan Cowles for his beautifully successful L3 flight.  Thanks for reading and to all the volunteers who made Plaster Blaster 2013 an awesome event!


David Reese said...

We did a bunch of work on thermite and found that the best way to ensure a quick ignition is good surface prep, i.e., having a mold release-free inner port with AP/binder exposed. CTI grains come straight off the mandrel and are pretty slick on the inside, so a quick scuff should help ignition time a lot. (AT grains are usually drilled, so this step can be skipped.)

G Frickin' Muneh said...

Great advice. Thanks, David!

Joyce said...

hi greg!
just catching up on your posts! what video camera are you using for your onboard?
that sucks about PB losing their waiver... =(
talk to you later!

G Frickin' Muneh said...

Hi, Joyce. I always use the 808 #16 v2 cameras commonly available on eBay:

Yeah some key folks in the club continue to seek a new FAA waiver nearby but there's no guarantee we'll be back in the air before our summer break Jul-Sept. Bummer.