Tuesday, March 20, 2018

Lucerne, March 2018 was a washout

I was excited to finally fly an Aerotech 98mm, 2-grain, L2500 Super Thunder with stainless steel forward closure at Lucerne.  It was raining lightly in North County SD as I left to drive up that way.  It continued to rain, on and off, over the drive until I got through Apple Valley... where it worsened.  As I got closer to the dry lake bed the rain further increased.  Hmph.  I turned around and headed home at the pink X below:
Ocenaside to Lucerne 2
That's the closest I've been to Lucern in nearly a year and a half. Better luck next month.

Saturday, March 17, 2018

Holtville Havoc II - March 3-5, 2018

Holtville Havoc II was supposed to see reasonable conditions on Friday, terrible conditions on Saturday, and brilliant conditions on Sunday.  I can attest that Friday amazed, Saturday was flyable until about noon, and I wasn't there on Sunday.  Here's a group photo and the rest of my photos from Saturday:
I had just one flight planned, on Friday, for this three-day event: the mighty CTI M6400 Vmax!  I had mostly prepped my L3 vessel, a 7.5" Nike Smoke, when I realized two problems with the reload.  The first was that the now aging resin, Dow PAPI 901 [polymeric with MDI], included with the reload was not curing from the day before.  It was thickening but not curing.  Secondly I could not fit the nozzle/liner/seal disc assembly into my Dr. Rocket 98/10240 casing.  With the forward closure fully threaded into the case I did not have sufficient depth to thread the aft nozzle ring into place.  Based on these two issues I scrapped this one flight so nothing to report here. I'll see what CTI recommends as next steps.  :(
     I was trying to get that flight out of the way on Friday to free Saturday for two L3 attempts.  Both Larry Hermanson and Cris Erving pulled their L3 flights together that morning because the weather was unexpectedly good.  Larry and Cris finished prepping at nearly the same time and got set up on the two 500' pads.  Larry was first with a CTI M1401 White which seemed successful.  Cris went second on an Aerotech M1500 Mojave Green and also ascended successfully:

Both flyers seemed positive on their way out to retrieve their rockets. Larry retrieved his first and was indeed successful.  Congratulations, Larry!  Cris took a bit longer to retrieve his.  Upon seeing his rocket I learned that his main had not ejected properly so he's going to try again in April.  Props for an amazing launch, all!

Sunday, March 4, 2018

Holtville, 2/2018 launch

Howdy, ya'll.  I've been absent from this blog for awhile.  This was not my intent and I hope I'm back for some time to come.

I attended the February launch at Holtville and here are my photo selects.  I'm quite sure that Mark Treseder shot some of those. Teamwork! I flew only my trusty 3" Nike Smoke on a CTI 540I470 White Thunder:
I had no doubt that this little rocket would withstand the motor's substantial max Q and, surprisingly, I could see it all the way to the ground under chute.  Is my vision improving?  Cheers!

Wednesday, March 15, 2017

100,000+ blog views!

Thank you, loyal readers, and I hope to increase my content output as 2017 proceeds.  Fly fast! Fly high!

Sunday, January 8, 2017

Holtville, Jan. 7, 2017 - TWO successful L3s! In 4K!

Frank Hermes AND River made it out to Holtville yesterday so those were already wins right there. Congratulations to Mark Treseder and Dave Nord who successfully earned their L3 yesterday for NAR and Tripoli, respectively:

I brought a couple of things to fly but instead opted to shoot mostly 4K video with my new GoPro Hero 5 camera. I just watched the above video on a 4K TV and it looks so crisp! Also the 240 fps slow-mo has been upgraded from 480p previously to 720p natively and I then upscale it nearly 3x into 4K. Fun!

Sunday, January 1, 2017

Lucerne Dry Lake, November 2016: The L1500 is a bad-ass!

As noted previously, and now that it seems to be out of production, my Madcow's 8" Mega Cowabunga was finally complete and ready to go.  I selected Aerotech's 98/5120 5089L1500 Blue Thunder beastie for a first flight and that was a good, thrusty choice as the hefty stub weighed 39 lbs on the pad.

Near the beginning of the video I included a CD3 ejection test with a 16g cartridge, 98/2560 motor assembly, and three shear pins as a worst-case pressure combination.  I also seek to minimize nosecone velocity since it alone weighs 10 pounds and I want to optimize separation and stress/strain at ejection.  This 16g cartridge was so gentle that I bumped up to 25g for the flight to add margin.
     The motor defied thermodynamics and self-assembled (😁) without issue. I followed Aerotech's revised assembly guidelines that now include bonding of grains to the liner for certain reloads:

This also represented the inaugural test of my 3D printed electronics bay for a stroll.  It houses two Featherweight Raven altimeters with Power Perches and the two halves are bolted through against the airframe wall and down against the top centering ring like so:

I used a stock, heftier CTI dipped match for ignition which proceeded expeditiously.  From a distance the rocket appeared to wobble a bit off the rod but stability should be rock solid so... more on that in a bit.  Again I used a deployment bag for a 12' Rocketman 'chute and both proved good choices as recovery proceeded in a beautifully uncomplicated manner:

Here are the data from the altimeters in very solid agreement:
  • Raven 1 (70G/30G) peaks [graph, tabular]:
    • Altitude, barometric: 6,208'
    • Velocity: 541 MPH
    • Acceleration, axial:  11.44G
    • Acceleration, lateral: 8.93G
  • Raven 3 (70G/30G) peaks [graph, tabular]:
    • Altitude, barometric: 6,182'
    • Velocity: 545 MPH
    • Acceleration, axial:  11.67G
    • Acceleration, lateral: 9.64G
  • Averages:
    • Altitude: 6, 195'
    • Velocity: 543 MPH
    • Acceleration, axial: 11.55G
    • Acceleration, lateral: 9.29G
Now about that liftoff torque... It took several views of the slow-mo pad video to (mostly) realize what happened. Lucerne's pads use a hinge as an airframe support at the bottom of the rail and I probably did not have that aligned axially with the rail slot. Additionally it's now obvious to me that nozzle's throat was not aligned with the apex of the roof-shaped thrust deflector. This high-thrust motor therefore vectored its thrust toward the camera and induced a clockwise moment of the pad from the thrust deflector upward. Now why would everything above the pad's legs be allowed to rotate ~70 degrees? No idea but, rest assured, I'll be checking that and other alignments from now on. Here's the unfortunate but minor and reparable damage to the bottom 1515 Delrin rail guide:

Overall I consider this flight to have rocked! Subsequently I purchaseed both CTI 4807L3150 Vmax and AT 4668L2500 Super Thunder reloads for future, authoritative sky-hole-punching.  Oh how the viciousness will delight.

Friday, November 25, 2016

Holtville: October 11, 2016 launch report

I didn't feel like packing that morning but, rather than shirking all responsibility, I elected to throw the trusty 2.6" Madcow Nike Smoke and minimally supportive gear in the car.  I also had that CTI/AMW 542I297 Skidmark that failed to fire in DRM mark II at LDRS so that was handy for this robust, 38mm-motor-mount beastie.  Finally, and most importantly, I wanted to test the Jolly Logic Chute Release gifted by my parents in September.  That site link covers the device thoroughly but this small, non-pyrotechnic parachute tether will now figure prominently in my electronics arsenal.  I somehow failed to secure liftoff video or photos but will attest to the perfection of the flight and single-volume, dual-deploy recovery.  Here are the other photos I captured that day as already shared with the Tripoli SD email distribution.  Oh and it's quite a rare bonus that I missed landing on the runway by about 8 feet this time:

I think I set the device for 500' to unbind the parachute but it looked more like 200' to me.  Next time I'll try 700-800' and see how that looks.  Note that Holtville is very close to sea level so this wasn't an MSL/AGL disagreement.  In summary: git one and git 'er done, 'Merica!

Thursday, November 24, 2016

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Sunday, November 20, 2016

Belated: LDRS - June 2016 launch report

I haven't felt much like blogging in recent months.  Could you tell?  Well I'm attempting to catch up now so I suppose that's something... onward and upward.

LDRS was conveniently hosted by ROCstock.org at Lucerne Dry Lake this year in June.  The San Diego club carved out a cozy little portion of the parking area a couple of rows back on the east side.  East side represent!  Mark Treseder was kind enough to shoot photos of the event using my camera and they're on Flickr if you'd like to glimpse into the recent past.
     I've wanted to fly Der Red Mix mark II fully loaded for some years now and this third flight seemed like a great time to try.  My aging Flip Mino HD's battery gave up the ghost unbeknownst to me until I was prepping the flight.   As such I have only ground-based slow-mo and hand-held iPhone 6s slow-mo footie but it's still sort of a good time:

You might recall that I took some airframe damage at the top of the tube, patched that at home, then spent literally hours on the playa sanding the tube interior and nose cone shoulder trying to make the nose cone fit.  In the end I got close enough but still had to use 2" wide Gorilla tape to create a gap at the top of the shoulder so the base would fit and move properly during ejection.  You can see the [tape] gap between the two 8 decals in this liftoff shot,  That did, however, shift the CG north a bit thus adding bonus stability margin (Photo Mark Treseder):
Skidmarks remain my personal motors of choice for this clustered/air-start vehicle so I stocked up on a central 2304K815 as the ground-start motor.  As always I got the thing moving up and away with this single motor before attempting to ignite subsequent motor pairs.  Once off the ground I use both Raven 1 and Raven 3 altimeters in series to theoretically fire 2x 543I297 then 2x 305H226 then 2x more 305H226.  For this third flight I set the air-start delays to 0.1s to maximize seamless titanium amazingness but noted two problems: 1) Only one of the I297s fired and 2) The gaps between motor pairs was more like 1-2 seconds.  I still have no idea what happened with the I297 pair's delay since the capacitor should have been fully charged at that point but all the other motors fired at some point.  If you look at the graph links below you'll see that the second pair of H226 motors were staggered unintentionally.  Also the missing I297's ematch had fired so I suppose this was a rare time when a pyrodex pellet missed its spark:
     Here are the data from the altimeters and both four-phase (really 5-phase) graphs look quite interesting (average altitude: 4,925' AGL) :
Oh and I forgot to mention that deployment bags rock!  The previously documented damage to DRM mark II was cause by an unnecessarily steep launch angle mandated by the RSO.  I was not interested in a second set of repairs and remembered that I have a couple of Rocketman deployment bags in storage.  I used to think of them as parachute blast protectors back when I was using black powder for direct ejection.  I have since moved all my large rockets to the CD3 CO2 system so melting/burning is no longer an issue.  Remember that the primary function of a deployment bag is to gradually and gently allow a parachute to inflate thus eliminating the shock of unhindered inflation.  I'm happy to report that zero incremental damage was done to my semi-fragile repairs on this flight so I'm all over deployment bags once again.
     I had planned a second flight but, despite significant amounts of work on the Madcow Rocketry Mega Cowabunga, I could not pull that one together.  Thanks for hanging in despite the protracted gap.