Holtville, May the 4th (be with you), 2024

Another mostly beautiful flying day in the SD (Imperial0 desert.  Flying fun was had by all.

I'm so grateful for the resurgence in interest in space exploration and hobby rocketry's a great element of  this pursuit.  Yesterday's launch continued to see new flyers interested in the hobby:

Holtville, April 6, 2024

Another great Holtville launch with astonishingly good flying conditions.

That day would have been my mom's BD so I flew the AT Cheetah she built probably 20 years ago in her honor:

 

Holtville April 1, 2023

I drove out earlier than usuall to witness Ryan E's L3 cert attempt. He succeeded with a beautiful ascent on at AT M1780NT and a slow descent and perfect recovery. Here's the vid:

Holtville Havoc 2022

Holtville Havoc 2022 featured one of the finest flying days I can recall at this launch site.  I also finally flew my highest thrust motor yet, the CTI 86434M6400 Vmax (1,626 lbf max), and what a fine beast it was...

...with a 13ft 4in flame!

I had always sort of remained in awe of this particular motor.  There are many punchier motors in production, or otherwise bespoke, but this is the highest thrust commercial motor I'm aware of certified for use in CA; at least is was before Vmax propellant was discontinued.  :(  I had built the motor awhile back then realized it wouldn't seem to fit in my Aerotech hardware.  So then, about a year later, I purchased a CTI Pro98/4G motor hardware set and solved that particular problem.  

    I was a bit out of practice, since I have't flown many rockets in the last couple of years, but everything seemed to come together.  Except of course that I had lost my CD3 ejection system on my Mega Cowabunga flight at Lucerne.  Luckily I had another set purchased from Kenny Harkema so I would have at least one CD3 for main ejection.  I've covered flights with this rocket in previous entries so I'll refer you to older blog posts if you'd like to understand those details.

    I'd elected to use the CTI supplied igniter which was quite old and failed to ignite the motor on the first try.  Paul Snow kindly supplied one of his igniters for my second attempt.  Russ Sands also kindly offered to drive me out to the far pad to reinstall this igniter greatly accelerating recycle time; there are many kind folks in this hobby.  :)

    On this second launch attempt there was a delay for several seconds then the motor roared to life lofting the 50.4lb rocket skyward.  Honestly the ascent struck me as about as fast as any other rocket I remember seeing that day.  I also recall that there was some erosive burning of propellant, despite the grain bonding, and there was a loud pop near motor burnout.  Cool.

    The drogue charge popped just about at apogee but the resultant force was greater than I'd anticipated; oh well "blow it apart or blow it up".  The excessive, resultant force caused the weighted nosecone to pop off at apogee as well and the main chute tangled up.  Grrr...

    Jim Deveau, the club's newest TAP member, also kindly offered to help me retrieve the rocket in his dune buggy; again kindness knows no bounds in the San Diego club.  My CTI tracker led us right to the landing site.  The descent was slower than it could have been, considering the 'chute foul, but the vessel still impacted the ground pretty hard.  Despite the relatively hard impact the rocket seems quite easily reparable to me.

    According to the average of my Raven 3&4 altimeters the rocket achieved 7,310' altitude, after accelerating to ~44Gs, and maxing out at 631MPH.

    Thanks to Mark Treseder for capturing the vast majority of photos with my camera!  And thanks again to all the kind rocketeers who assisted me this weekend.

I have a few more photos scattered about so I'll add those soon.  Oh and here's the altimeter data if you'd like to take a peek.

Raven3/4 data - graph | motor | tabular:

  

P.S.  Here are photos of a) the motor hardware and reload and 2) the largely intact components after a fouled recovery... minor repairs imminent.:

Holtville April 2, 2022

Oh hi there.  I'm known to blog... occasionally.  

I attended the most recent launch at Holtville, CA and a fine day it was.  I flew only a CTI 168H410 Vmax reload in my DarkStar mini.  It sorta got up and went as expected.  I captured no pixels of this flight except recovery which was close and convenient for once.

The rest of the launch I sought to regain some photographic skills.  This new camera astounds but I'm still struggling with focus a bit.  Today I shot primarily using manual focus.  I'm also using a 1.4x II teleconverter as this 1Dx mark III is full-frame and that robs a bit of reach so the loss of one stop (f/2.8=>f/4.0) seems worth it.  

I captured two nifty flights...

The first was Russ Sands' rocket on an AT 7301M4500 Super Thunder reload.  It, too, got up and went quite briskly.  Russ was able to fully recover the rocket so a fine flight it was.

The second was Paul Snow's "Intercontinental Transport" and he's authored that very thorough build thread on RocketryForum.com.   This was another beautiful flight and the shock cord had conveniently snagged on the airframe providing a gentler horizontal descent. 

I'm looking forward to flying more as the season progresses.  I also learned that the SD club's planning a second flight of the Trident at LDRS 40 at Lucerne Dry Lake June 9-12 of this year.  Be there!

Holtville June 5, 2021

It's been 15 months since my last launch... but that pandemic pause ended today.  

I drove out to Holtville and experienced a rather extreme temperature gradient in moving from coast to the eastern CA desert: 63˚F to 103˚F (108˚F on the way back!).  Wow.  I was only able to fly one rocket but that felt good indeed.  Luckily I've been hitting the gym on alternate days in recent years (except for closures driven by pathogen precautions) and felt quite solid walking in the heat today.

I flew the CTI 1750K650 Pink (Pro54/5G) motor in my Polecat Aerospace [White :) ] Raven.  The motor was awesome but I'll need to microadjust focus on my new camera:

[The focus dot was clearly on the rocket before liftoff but the focal plane's roughly 15 feet behind the rocket in the photo.  All prior test photos with this camera have been tack sharp with all lenses so it must be this particular lens.]

But back to rawkitz... The ascent was both loud and immediate.  I'd trimmed the default 21 second delay down to ~16.5s but I think it was still roughly 1-2 seconds too long.  Upon ejection the Jolly Logic Chute Release failed to retain the parachute so I experienced full inflation at ~10,000ft; the rubber bands must have been too loose around the 'chute as I've experienced nothing but success with this product before.   The rocket seemed to hang roughly centered over the launch area for about the first 2,000ft of descent but then began drifting north.  I could clearly see the fluorescent yellow 'chute for the entire descent and my Com-Spec beacon continuously beeped away as well.

I was clearly out of practice as I'd forgotten the cardinal rule: always take water!  Luckily Andy B. kindly drove out to me and handed a cold bottle of hydrogen hydroxide to me.  He also waited for me as I crossed the airport's north boundary and walked perhaps another 100 yards and right up to my rocket.  It was intact except for a roughly 3" zipper due to 'chute poppage.  Paul Snow shared some nifty repair advice so perhaps I'll give that a try rather than shortening the airframe.

Two quick notes:

1. I had packed my pair of Rockontrollers but forgot to charge them.  Despite remaining uncharged for 2+ years these units still served to launch my rocket wirelessly.  Nice work, Frank!  And thanks for pushing those buttons, Paul!  And thanks, Daniel, for setting up the 200ft pad!
2. My new camera shoots at 16fps.  I only captured three frames of the liftoff during its rapid ascent but it might prove interesting to estimate acceleration rates with these [back focused] photos.  More soon.

I'm now fully immunized

I got my second Moderna shot roughly one month ago.  I can't wait until everyone proudly declares they've been immunized.  Yay, medical progress!

Building resumed...

I've resumed building the 7.5" V2 with a 75mm motor mount.  I applied the fin fillets last night:

























I still need to seal the exterior and sand it smooth.   I've had Aeropoxy Light in my garage for years and only opened it up this morning:

I applied the paste to some test plywood this morning as well as slightly dilute and more dilute (with isopropyl alcohol).  I covered 1/2 of these test swaths with plastic film to evaluate that smoothness/uniformity knob.  It's curing now and I'll try sanding the test block today. More soon.

Lucerne, 2/8/20

Aerotech M4500 Super Thunder (1247 lb•f max thrust)...  Epic:



You'll notice that initial tilt straightened right out to vertical.  Now let's back up before the launch...

First off I seem to have misplaced my stainless steel seal disc, required for AT Super Thunder 98mm reloads, at home.  I have yet to really dig for it but emailed David Reese, fellow TAP and proprietor of Wildman West Rocketry, and he Kindly said he'd loan or sell his spare to me.  I purchased his so now there are two such 98mm discs in my home; handy.

I'd performed a bit of prep the night before but, as previously noted, I'm slow.  The wind was kicking up from zero to substantial as my prep wrapped up.  I was committed to launching, however, so I just kept moving forward.  As I neared the LCO table I encountered Kurt Gugisberg; the TAP who'd signed off on my L3.  He noted that there wasn't a 1515 rail at the 500' pads but offered to grab one from the club's trailer.  He then kindly walked with me out to the pad and helped me load up this 44lb beast.

Earlier this month (Feb) I learned that my GoPro Hero 5 camera shoots 240 fps in 720p at Holtville.  I'd never noticed the resolution increase from 480p since I'd apparently never explored the camera's UI.  Dum.  In any event I was all psyched to shoot this M4500 liftoff at 240fps and was indeed running the camera in this mode while the rocket was on the pad.

Then I headed in to the LCO table, manned by David Reese, only to learn that I'd neglected to connect the installed initiator leads.  Dum.  I then walked out to the pad pausing the GoPro on the way.  I connected the leads and headed back to the table.  Note that I hadn't restarted the camera.  I realized this but the wind seemed to steadily increase so I opted to skip the slow-mo vid of this launch and instead shot the above still sequence hand-held.

Liftoff was essentially instantaneous and the Mega Cowabunga quickly roared to a lofty altitude.  I'd estimate that flame to be roughly 10-11 feet long.  Again Epic.   I saw the ejection at apogee but then lost site of the rocket under 'chute.  Luckily I had a clean Comm-Spec transmitter signal and began walking downwind (East) following that signal.  I ended up trekking 2 miles E-NE and found the rocket intact:

I'm estimating the endpoints of the above line drawn in Google Earth but they're pretty close.  Kurt noted that the owner of that property where my rocket landed was speculated to have gathered many previous rockets and may have them in a spare room.  Noted, Kurt, but mine escaped such a fate this day.

My new Raven4 altimeter seems to have worked flawlessly alongside the Raven3.  The average of the two devices is:

Altitude (AGL): 9,668 ft
Speed: 811 MPH (speed of sound is 771MPH @ 73˚F so mach 1.05)
Acceleration: 37.6 gees

Here are screen grabs from the Featherweight Interface Program:

Raven4: (altitude, speed, accel)(tabular)(acceleration only, thrust curve)


Raven3: (altitude, speed, accel)(tabular)(acceleration only, thrust curve)


As I slowly walked the Meg'Cow' back toward my car I noticed that the sustained winds had shut the range down.  Kurt then handed me both 1515 rail guides as they'd separated from the rocket under intense acceleration.  Oops.  I'm grateful the ascent ended up so vertical!

So I remain a big fan of Aerotech Super Thunder propellant.  Having now flown their L2500 and M4500 I'd like to fly the M6000; as prompted by David Reese.  Look for this flight in the future but I still have to fly the CTI M6400; hopefully at Holtville Havoc in March.  Thanks for reading!

Addendum: I forgot to mention that I lost my CD3 (CO2) assembly.  It ejected the 'chute then ejected itself from its attachment to the shock cord.  If you found a CD3 assembly on Lucerne Dry Lake after the launch please consider returning it.  Thank you.

Holtville 2/1/2020

Once again I've been too busy at work to pack/prep for this month's launch at Holtville.  I shot even more vid than usual, however:

And here are my still photos.

I've made two intriguing discoveries with my GoPro Hero 5 black: 1) The GoPro app rules and serves as the POV previewer I've craved and 2) Somehow I never checked for updated resolutions when I bought this hero 5.  After shooting the above vids I learned that the Hero 5 supports 240 fps shooting in 720p!!  So this will be my last vid shot in 480p and scaled to 720p.  I also learned that the Hero 8 shoots 240fps in 1080p.  So, now that I've discovered 720p/240, perhaps it's time for an upgrade.  Enjoy.