Sunday, December 7, 2014

Our first Holtville launch... 16x slower

I'm slow.  Only recently did I figure out that the GoPro Hero3+ I've had for a year features a 240 fps mode.  If I slow that down another 50% during editing I'm now showing hawt akshun at an effective 480 fps! Perfect for rocket liftoffs at our new launch site at Holtville Airport right?  [Watch on YouTube in full-screen, 720p with the audio cranked up for best results]:

My LOC Bullet finally bit the bullet with an old AT J420 Redline motor. Unlike a fine wine... Redline motors age the worst of any propellant I've yet encountered.  This failure was similar to an AT I366 Redline failure I experienced a couple of years back yet... only yesterday did I figure out that, upon ignition, the delay begins burning but the propellant takes several seconds to pressure up (even if one scuffs up the grain surfaces vigorously).  So, once it does lift off, there's little delay left and the ejection charge fires near Max Q thus shredding your recovery system, destroying your Comm-Spec tracker, and inexplicably hurling your nose cone several hundred feed away (despite a perfectly straight ascent).  Russ Sands spotted it right away yet I must have been in denial.  Yes I did find it positioned precisely as pictured:
I also flew my DarkStar Lite on a slightly less old AT H128 White Lightnin'. It's interesting to draw attention to the fluctuating thrust on the video.  Our new launch site is an extra half hour from my house but it's a cool, retired airport.  The concrete runways occupy only a small percentage of the land area on the site yet my DS Lite managed to miss the soft dirt by that much:
The motor retainer cap dented but still works fine... ahhhhhh, probability. I hope to fly an M6400 at the new site soon and really break 'er in!  Sound carries very efficiently there so ear plugs might be in order for the audibly sensitive.

2 comments:

Jose Garcia said...

The old airport is perfect for launches. I was there this past weekend and found that the fence was fixed, so no more casually walking through for me. Anyways, did you have to get a permit or special permission to launch there? I don't fly any high power stuff, just D-G motors as an enthusiast. Thanks. Nice footage btw.

G Frickin' Muneh said...

Hi, Jose. We fly the first full weekend of every month so come on out this next weekend and fly with us: http://www.tripolisandiego.org/launchsite.html