Friday, December 30, 2011

Lucerne - December 2011 launch report

Despite the cold morning it was sunny and clear most of the day with essentially zero wind.  Every once in awhile Madre Nature gives back. For awhile now I've been wanting to fly the AT 486I59 Warp9 8-second end-burner with a cored White Lightning kicker on the nozzle end:

Per the instructions I used some Gorilla Glue to bond the end-burning grain place and then liberally coated the liner with grease to [hopefully] minimize casing damage.  This was also the first time I'd tried the new Featherweight Altimeters magnetic switch armed externally using only a rare earth magnet:

Yeah the wires are long but I wanted to be able to swap the switch around to other electronics bays as necessary.  I didn't capture any video or pictures of the liftoff but it kinda sucked.  The initial kick wasn't as great as I'd calculated and my .38 Spatial immediately headed north after leaving the end of the rail.  It arc'd out toward the mountain range and the only way I knew the main ejection had kicked was that my Comm-Spec transmitter signal shot up about when I'd expected based on the visual trajectory.  From the following flight graph you can see that I still managed to attain ~2,200' of altitude and, based on the post-main slope of the altitude curve, the descent on the 12" 'chute was probably too fast at about 55fps/32MPH:

I say probably because this rocket is a tank and I found it completely intact well over 1.5 miles north.  You can just see a thin, horizontal line of cars to the right of the hanging smoke trail if you click the image below:

This was, by far, the longest I've walked north at Lucerne and, for reference, I shot another photo of the power lines near the base of the huge mountain from that position:

My cellphone has a pretty wide angle lens but you still get the idea.  I was about 80% of the way up the illuvial fan and I'm glad I didn't get caught in the power lines!  Unfortunately the greased liner didn't protect my awesome 38/480 Dr. Rocket Millennium edition casing and the anodizing's partially burned now:

I'm sad but I've flown probably 10 reloads in there and it appears structurally sound (no bubbling).
     I'll reiterate that I'm a very slow on rocket prep and recovery so I only had time for one more flight as the awesome ROC volunteers were talking of tearing the range down.  Rob Greenlaw was parked next to me and he agreed to a drag race with our fiberglass 4" Nike Smokes on CTI 1408K2045 Vmax motors.  I'll forego my typical drag race suspense and simply tell you that Rob won:

Good for Rob and I've already requested a rematch!

Thursday, December 29, 2011

Belated thanks to Mike "Sparky" Jerauld!

Near the end of this year's Plaster Blaster event Sparky, president of DART rocketry in SD,  asked me to check out a rocket he'd found years ago and was trying to identify.  My jaw dropped when I realized he'd found my long-lost minimum diameter 38mm design!
I'd flown/lost it at Plaster City on a CTI 512I285 classic motor.  This flight predated my obsession with radio tracking as an invaluable insurance policy but I was out there with "Eagle Eyes" LL so what could go wrong?  Well both of us lost site of it after burnout and, despite scouring the area for over an hour, were unable to find it and gave up.  I'm not sure exactly who found it but Mike returned it completely intact including my long-lost Pro38 4G casing.  So thanks again and props to Mr. Jerauld!

Lesson learned: I should travel back in time and include a radio tracker before the flight.

Thursday, December 15, 2011

Wow it's actually 16,547 page views!

Google just redesigned the profile page for and it now clarifies that the 'page' views I've been tracking are actually profile views.  So that counter in the lower right of this page is correct. Thanks for reading, peeps!

Thursday, November 24, 2011

PB2k11: Third annual M Moonburner drag race details

After posting two foreshadowing images below I'm finally getting around to documenting our nifty drag race three weeks ago.  I had trouble editing the Flip Slide video in Final Cut Pro 7.03 for some reason so I threw this together in Final Cut Pro X:

[I'm not really a huge fan of that software yet as it seems to be half way between iMovie and v7.03 in capability.]  Three of us flew the CTI 7521M840 and Mark Clauson chose the AT M650.  A HUGE thanks to Joyce Chan who skillfully photographed our drag race and was kind enough to share her source files with me.  Please head over to her site for larger versions or to buy prints of these or any of her other awesome shots:
L-to-R: Art/Tom Just, Frank Hermes, yours truly, Mark Clauson

Mark smoked us all with his minimum diameter L3 vessel on the M650!

I was second off the pad, then Art, then Frank.  I honestly thought we M840 flyers would have had an ignition advantage because there's a 29mm propellant grain with an embedded pyrodex pellet at the top of the core.  That plus the insane 459 pounds of initial thrust has me scratching my head.  Perhaps Mark was using a special igniter but, whatever the reason, he won the liftoff cleanly.
     I again used my Beeline GPS module to track the rocket as it was well out of site.  I threw in the beacon as backup and thought I'd need if as my Yaesu radio didn't receive any distance data until about 20 seconds before the rocket landed.  Not sure what's up with that but, in the end, the Beeline did the job and the Google Earth data was robust as shown in the post below.

As a fun aside we all kicked in $20 and employed a scoring equation including liftoff rank, peak altitude, and distance from the pad (highest score takes all):

Mark won with the highest overall score so congrats again!  While Frank didn't win this year he was the only participant to incur zero damage after a clean recovery.  Mark hit a power line on the way down and burned a 1/2" hole through the airframe and aft motor closure.  Art's 1/4" Kevlar shock cord snapped but he got all the parts back.  Mine suffered a hard impact that ruined my motor retainer ring and it took hours to free my motor casing.  I was able to salvage it however and will replace the ring with 10-32 screws through the retainer side wall.  Here my altimeter data if you're interested:

ARTS2 - tabular data
ARTS2 - graphical data
ARTS2 - motor performance estimate (7521M840->7045M989)
ARTS2 - CD plot
Raven - tabular data
Raven - graphical data

Thanks to all who participated and I look forward to another fun drag race at PB2k12.

Tuesday, November 15, 2011

I posted my Plaster Blaster 2011 shots from Sunday

And you'll find them here.  I also cleaned up my M840 drag race GPS data and plotted in Google Earth (looking east):
More info coming this week-ish so hang tight.

Sunday, November 13, 2011

Productive Sunday

I'm a week late on my Plaster Blaster 2011 entry but I'm still waiting for a few elements to come together.  I'll foreshadow a problem with an otherwise great M840 drag race flight last weekend: my Slimline motor retainer ring would not unscrew due to an impact with some harder soil.  Frank Hermes suggested that the retainer tube was probably out of round due to angled impact and I think he was right.  I started my Sunday trying to resolve that and get my motor casing out.

After 45 mins. of trying other methods I finally busted out my Dremel tool to grind a notch in the slot of the Slimline retainer ring.  I then used a chisel to wedge down into the threads and snapped the ring at that spot.  I was finally able to pop out the ring and extract my Pro75 6G casing. Although the retainer's threads are trashed I think I can drill into the sides of the retainer tube, tap them, and use tiny screws to retain future motors.  This is cool because I really didn't want to trash the booster despite a heavier-duty version being on deck:

Those who have flown moonburner reloads know that they rank among the more difficult cleanup jobs; especially when stuck in a booster and untouched for a week!  I was able to get the casing apart and the liner out without issue.  As expected some threaded parts and the casing interior were filthy despite liberal use of grease during assembly of the reload.  I emptied my tall-ish office trashcan, placed my casing into that, and poured hot, soapy water down into the casing.  I repeated the fill and then added a bit of white vinegar to the solution.  After soaking for a half-hour I flipped it over and started cleaning with a toothbrush taped to a dowel.  A few iterations later I then dried the casing and busted out the screwdriver to scrape and the brake cleaner to dissolve the crud.  This process took almost two hours in total today but my casing and parts are quite clean now.
    During the soak I started repairing other rockets.  My Madcow Squat suffered a minor zipper during the I445 drag race over a year ago. The short body tube is cardboard so I simply wrapped a swath of Gorilla Tape around the top of the tube.  It looks pretty cool and should survive another I445 flight.

    My '.38 Spatial' suffered a narrow Kevlar zipper in the payload section on its J350 flight.  I used a length of 38mm coupler, two layers of release film, a slice of 38mm body tube, and carbon-fiber-loaded-epoxy to patch that up.  I then wrapped the assembly in shrink tape and applied heat with a heat gun. This shrunk the film very tightly and I expect the gap to cure/fill quite nicely.

    On its last flight my Loc Bullet suffered a 1x2" zipper/chunk due to an excessively long J500 delay.  I used a technique similar to the above but this time I sandwiched a layer of carbon fiber fabric in the repaired area.  It's worth a try as I was about to trash this rocket and start again.

    I also scraped some unintended and ugly primer drips off of the 4' long payload section remnant of the otherwise lost Viciously Mean Machine.  It looks pretty cool now and I think I'll fly it with the Fity-Fo booster:

    Saturday, October 15, 2011

    If I were 2.72 miles tall...

    ...the view might look something like this:

    Here's the onboard video from my M1230 Imax flight this last Saturday at Roctober/Lucerne Dry Lake (best in 720p, full screen)(note the ill-fated desert beetle scaling the igniter just before the flame deluge):

    This was my first solid, high-altitude Beeline GPS data set as plotted in Google Earth with a peak altitude of 14,434' AGL and recovery 0.8 miles S-SE from the pad:

    It's interesting to note the the ARTS2 reported a peak barometric altitude of 13,915' and the Raven gave 13,925' for an average of 13,920'.  That's the closest I've ever seen two altimeters! (Only 0.07% disagreement).  I also passed mach 1 at about 3 seconds into the boost on the way to a peak of mach 1.15 or ~887MPH.  Here are links to the data images if you're interested:

    Raven - tabular
    Raven - graph
    ARTS2 - tabular
    ARTS2 - graph
    ARTS2 - motor performance (M1230 -> M1374)
    ARTS2 - coefficient of drag performance

    Next up is that same rocket on an M840 White moonburner at Plaster Blaster 2011 from November 4-6.  We're hoping to pull together a drag race but approval is pending.  You should come check it out!

    Update:  I forgot to include the cool liftoff shot by LL.  Unfortunately the full-size shot is significantly back-focused due to the lens sitting in the sun for awhile.  LL has razor sharp vision and manually focused about a half hour before the flight but even this smaller size rendering with significant sharpening is quite soft.   Not complaining... just explaining.  I recommend that you keep all your big lenses in the shade at all times if possible:

    Update 2 (4/3/12) - I just found two more cell phone photos from this flight: the GPS tracking shot and recovery photo:

    Thursday, September 15, 2011

    Belated: L585 with perfect dual deploy!

    My fourth and final flight at Plaster City's June '11 launch was my new 4" fiberglass Extreme DarkStar.  I've sort of resisted the 75mm motor class for a decade but now I'm into it.  I ran some calculations and the cost in $/N•s is identical between 75mm and 98mm reloads (~$0.06-0.10/N•s).  This means the overall cost is lower with identical impulse per $.   Big fan.
         The wind was kicking up big time but I was confident that dual deploy combined with shear pins would bring the rocket down reasonably close.  Unfortunately my keychain video camera died on the K740 flight below so I have no onboard or ground-based video. The pix are still good though.  KO snapped this prep shot and I like it! (ignore my photo credit as that's an artifact of batch export):

    Here's the pressure up:

    And liftoff... note the excessive wind blowing the plume:

    The ascent was arrow-straight but I lost site after apogee ejection because I was using CO2 deployment and a tiny drogue 'chute.  This was also my first time using the Beeline GPS unit because the fiberglass structure doesn't attenuate the signal.  Unfortunately I forgot to tape the unit down to the foam mount so I think it dropped to the bottom of the electronics bay on liftoff as my GPS altitude data was wonky.  I did receive what appeared to be directional information, however, so I started walking NW.  Then I heard a loud pop as the 4g main black powder charge blew at roughly 1200' as expected.  I watched the rest of the descent and it landed only ~1/4 mile NW of the launch site (closer than most flights in low wind!).  Luckily the dragging parachute caught on a bush so no damage was done by subsequent dragging.  Stupid mass convection.  Here's the Raven Altimeter data with a barometric peak altitude of 7,489':

    And here's the ARTS2 altimeter data with a barometric peak altitude of 7,233' for an average of 7,361' (1.39 miles) at sub-Mach velocity:

    I also ran the ARTS2 motor analysis and the report says it's an L680 (vs. the nominal L585).

    Finally the ARTS2 coefficient of drag was roughly 0.5 at peak velocity.

    I next plan to fly this rocket on the same propellant type but twice the motor size (M1230) so I expect roughly twice the altitude or ~14,000'.  Fingers crossed for October 8th!

    Tuesday, September 13, 2011

    Belated: K740 C-Star = Must try!

    From the June '11 Plaster City launch... I finally got around to editing this simple onboard video:

    The boost was loud and fast and I think I trimmed the delay to about 15 seconds.  The coast to apogee seems supa long.  I would have dropped in some frame grabs but the source video was overexposed for some reason and I didn't want to delay this entry further.  Oh and after about a well-heated, 15-minute hike north I located the goods via radio tracker:

    Saturday, July 23, 2011

    It's official + dedicated e-mail address

    I created a dedicated e-mail address for prospective L3 flyers yesterday (masked to prevent spamming d-heads from e-mail fishing):


    In sending that change to Debra I noticed that Tripoli's TAP page has been updated to include myself and Richard King Ph.D (a central CA flyer simultaneously advocated by Jack Garibaldi).

    Either address will work but the above is preferred and dedicated to the hobby.  Fly high, flyers!

    Monday, July 11, 2011

    "L3 First Try!"

    I've wanted to author a primer to help those aspiring to their Tripoli level 3 certification.  After sharing the initial draft I incorporated feedback from KO and Frank and here's the result:

    L3 First Try! v1.0f.pdf    (updated to v1f on 12/21/14)

    Enjoy and let me know if you have any additional feedback or questions.

    Wednesday, June 22, 2011

    Great TAP success!!

    Debra Koloms just informed me that I was promoted to Tripoli's L3 Technical Advisory Panel (TAP) and I'm elated!  I could not have attained this honor without Debra and the board's advocacy, the sponsorship of Jack Garibaldi, the support of Paul Snow and Kurt Gugisberg, and letters of recommendation from Frank Hermes and Kris Olmstead.

    Thank you all and I vow to do my very best to serve Tripoli and its membership for decades to come!

    Greg Smith
    TRA#8756, L3 TAP

    P.S. Here's Tripoli's official Level 3 process.

    Monday, June 20, 2011

    June '11 @ Plaster City: Polecat Aerospace Super Raven x 2

    For once I finished the video for these flights last week but have been remiss on my posting punctuality.  In any event I built the very pointy Super Raven kit from Jack Garibaldi at What's Up Hobby and it's a good time!  At this month's essentially wind-free Plaster  City launch I captured photos and vid of both flights so here goes...  First up was the CTI Pro38 I180 Skidmark with an HD keychain camera Gorilla-taped to the side:
    And a crop of the flame detail showing lovely mass convection:
    Next up was the CTI Pro38 H400 Vmax for a flight that was so fast that I reverted to a ground-based 30 fps video to show the fun:
    Here's the video featuring both flights (as always 720p full-screen viewing on YouTube satisfies best):

    The date/time info is whack and only the time is useful in a relative sense.  This was a great launch with solid weather and several folks whooped ass at our final launch before the summer break.  Special props to Mike Caplinger who achieved 21,127' feet with a K300 to best the Club's 20K President's Challenge!!

    Sunday, June 12, 2011

    NSL @ Lucerne 'blows'

    When I arrived at 9:15AM yesterday it was already too windy for my tastes.  KO prepped her L3 flight and got it on the pad at 1PM only to have the range shut down at 1:30 due to excessive wind.  I'm hoping she stayed overnight and tried again this morning as only minimal setup time would have been required.

    Saturday, June 4, 2011

    Finally... amazing Plaster City conditions!

    I had 4/4 successful flights at Plaster today with excellent conditions. I gathered so many photos and so much video and data that I'll plan to post thorough updates for each likely as separate entries.  Oh and I finally used my Big Red Bee Beeline GPS unit, Frank!  I'm spent so it's a shower then off to bed for me now.

    Tuesday, May 10, 2011

    ...and again. Plus Sport Rocketry Cover

    Everyone brace yourselves... Plaster City was once again blown out!  I arrived at 9:30 on Saturday morning to find gusts at 20MPH.  Two brave flyers still flew L motors and it turned out that this was a surface wind topping out at about 500'.  I was still marginally disgusted with the conditions and bailed before noon.  I admit that I'm a fair weather sort of flyer.
         On a happier note I also learned that one of my photos of Mike Worthen's J500G liftoff made the cover of NAR's Sport Rocketry magazine:
    Thanks to Larry Brand for linking me up with them.  They're sending me a copy as one can only get the magazine as part of a NAR membership.  Since NAR used to ban 'rebels' for flying G motors back in the early 80s I've elected to remain solely a Tripoli member.  I'm stoked that I could help the magazine, however.

    Sunday, April 3, 2011

    Blown out again + new blog gadgets + cute buddy

    The March Lucerne launch was windy enough that I didn't even unpack my car upon arrival.  Then, yesterday, the Plaster City weather report looked prohibitively windy so I fought the urge to again torture myself via long-drive-no-flying and stayed home.  I plan to hit Lucerne next weekend but we'll see. [Update: That was blown out too!!]
         I also added a search field to this blog and also a hit counter with graph there on the right.  Although the hit counter looks much higher than what Blogger currently reports, "Approximate Profile Views: 1334", but perhaps that's visits and the counter below increments page views?  Dunno but I'll leave it there for awhile anyway.  Signing off... here's a great shot of Zero by LL:

    Friday, March 25, 2011

    Sometimes ya gotta just give up on the video...

    I spent a whole bunch o' time since the beginning of March trying to get my new camera's video footage slowed down to look all cool. Ultimately I think that even 60 fps is inadequate to slow a fast rocket down. I punted on all the slow mo and just authored the best video I could here:
    Again I only had two flights that day because I was trying out my new 1D mark IV camera. If you have the means I highly recommend it... It is SO choice.
    I flew my Polecat Aerospace 4" V2 on a CTI Pro54 491I218 and it kicked ass outa there. Here's a cropped frame grab from the 1280x720x60p video:
    I retrieved that perfectly intact about 0.3 miles NW from the launch site. Then I set up my Loc Bullet on an AT J500 Mojave Green and I thank Daryl for setting up the reload for me. As I was setting the flight up I learned that the fella next to me was flying an AT I245 Mojave Green with a camera so we agreed to fly a drag race. It's interesting to note that Daryl provided a longer Aerotech delay that I thought was 14 seconds and I trimmed 2 seconds off that with my delay adjustment tool and AT adapter. In the video you might have noted that the burnout-to-apogee time was actually 15 seconds and the ejection was 5 seconds after that! So AT is now shipping 21-22 second delays? Dunno but that was WAY too long and my CF reinforced Bullet took a bunch of damage. It's probably time to retire that thing and rebuild one more similar to the original BSD design. Here are three frames of the drag race where I get my ass handed to me once again (the keychain video cam is Gorilla-taped to the left side of the Bullet on the right):
    I just remembered that KO pushed the button on that sequence so I take only partial credit for setting the camera up. Love those mach diamonds and 10 frames per second helps a bunch! Here are the rest of my shots from that launch as well.

    Thursday, March 10, 2011

    Working on March 2011 Plaster City launch report...

    ...and have been since Sunday. I finally have some 60 fps liftoff vid and I'm trying to get some good slow mo out of it yet continue to struggle. Here's an otherwise unrelated video of what my new camera should be capable of for reference (The 7D is a close cousin to my camera).

    Monday, February 7, 2011

    Plaster City Launch - Feb. 2011

    We benefitted from yet another late-winter, wind-free launch in the Imperial desert this last weekend. We're tremendously lucky to live in SoCal. I decided to be a Luddite and fly only motor ejection this weekend (no electronics) so I could fly more rockets and concentrate on video and photography. Shocker that I STILL only had two flights but at least the photos and vid didn't suffer. I posted numerous shots here (click play to start slideshow). Please post comments with corrections and/or motor info that I missed.

    First I flew my fiberglass 4" Madcow Nike Smoke on a CTI K940 White Thunder reload. The flight was amazingly kick-ass and was far faster than I'd expected after the slow K400 Green^3 flight last month. The liftoff thrust:weight was 28:1 for a good time. I walked about 1.25 miles S-SE to find this sucker with my radio beacon. Just call me "1-Mile Radius G". Here's the liftoff:
    I also Gorilla-Taped a $5 keychain camera to the side and the video is pretty good considering the convenience and cost benefits:
    [That looks way more compressed than the original raw footage so I'll need to figure that out and post a better version later.] I adjusted the delay to 11.5 seconds for this 8 lb. 14 oz. flight but you saw that was about 3-5 seconds too short and the 'chute popped way too early. Also the shock cord wrapped perfectly around the camera's lens on the descent thus cutting the usable video short. I'll get it right next time and recommend those cheap Ebay perv-cams. Oh and the flight video file consumed roughly 1.05GB for 25 minutes so a 2GB micro-SD card should suffice for most folks. I bought two 8GB cards because I didn't know so save yourself some dough.

    Then I flew my DarkStar Lite on an older AT I200 motor with perfect recovery just South of the launch site (note the inadvertent mini-roll of Gorilla Tape on the fin... D'oh!):

    I'm as shocked as you that it didn't also drift over 1 mile South. Cheers to another excellent launch at Lucerne next weekend!

    Sunday, January 30, 2011

    And... FINISHED!!

    Today I finished primary assembly of the Extreme DarkStar (right) and there's the final Nike Smoke my parents bought for me (left). [Update: While I was authoring this entry I figured out they'd shipped the wrong DarkStar fins to me. Awesome now that's it's friggin' built! The Nike Smoke is fine, however. Details below...]
    I still need to foam the fin slots, fillet the fins, drill vent holes and static port, attach the rail guides, and layout the electronics board but it'll fly next weekend on a CTI Pro75 6162M1675 Pink. Based on KO's previous flights this rocket seems to get about 3 feet per Newton-second of total impulse. As such I would estimate about 17,000-18,000' from that motor. I'll also fly it dual deploy but plan to run both a Beeline GPS transmitter and my workhorse tracker beacon to assure recovery. Here are some build details from previous weeks:
    On the above motor assembly I elected to use the SlimLine 75mm motor mount so no screws are required (unlike the AeroPac which is a very tight fit). I also left off the Kevlar strap as I prefer to link the recovery system to a drop-forged screw eye in the motor's forward closure. That longitudinal masking tape serves as a shim for the centering rings as the tube is tapered and they would have been loose during the cure otherwise.
    For some reason Wildman provided WAY too much tab depth on those fins but my new carbide-coated bandsaw blade cut through the 3/8" high stack like butta. That blade was spendy at over $100 but there really is no other way to cut fiberglass on a bandsaw with any reasonable blade life.
    I went retro and simply taped each fin pair on with manual alignment. This was a bit difficult because the slots were about 50% too wide for those fins. I chose to datum to the left side of each slot and they all look perfectly aligned to my eye. I'm now wondering if Wildman had intended to ship 3/16" thick fins with this kit? Hmmmm. Low and behold they WERE supposed to ship 3/16" fins as indicated in the kit specs. That's strange because the fin tabs matched the slot length correctly so I assumed they'd just messed up on the fin template. Maybe mine won't fly on any 75mm motor made then... Dammit.
    Above is another view of the simple yet effective fin attachment.
    Above is the electronics bay. Today I JB Welded those aluminum tubes to the sled so, apart layout out the board positions and switches it's all set to go. Wow I'm really bummed about that fin thing now. This was too much money and work to be uncertain of fin strength at this point.