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!!

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.

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.

...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.

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:

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.

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).

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!

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.

Lagger: Plaster City 1/1/11 Launch Report

The coolness of the date of this launch was exceeded only by the complete lack of wind and excellent flying conditions all day. The primary reason for this delayed report is that I was trying to improve the video I shot that day to no avail. My pictures sucked too so that's awesome.

Fiberglass Nike Smoke 4" - This is the kit mis padres purchased for me for Xmas (bah humbug :). It's designed like a tank with a weight to match -- 81 oz dry!! I purchased a Pro54 4-grain 1597K400 Green^3 reload from Jack. The liftoff was slower than I'd expected but, like all Nike Smokes, the thing flew straight as an arrow. I trimmed the delay to 11 seconds and ejection was about 1 second after apogee. I used a 48" parachute and the descent seemed slow until it got nearer the ground then it seemed speedier than I'd like. In any event it landed at the edge of the 'bowl' free of damage.

I think this kit needs some serious thrust so I purchased another 4-grain motor, the 1633K940 White Thunder, for its next flight. At the same time Jack offered me a mystery 4-grain motor for half-price. Others reportedly shied away earlier in the day but I wasn't skerd and bought it anyway. When I got it home I opened the package to find "VM" written on the ejection cap so I'm forced to assume it's the 1408K2045 Vmax. Score!! So I'll reserve that for the third flight of my new Smoke and it should be scootin'.

.38 Spatial - I last flew this minimum diameter, carbon-fiber-over-phenolic design on an I284 to ~9100'. The next logical step on the way to the insane 1115J530 was the J350 I've had sitting in my motor box for many years now. As always these minimum diameter flights take way too long to prep and there never seems to be enough internal room to fit everything despite previous successes there. Once on the pad I had trouble locating the Raven's arm button so I pulled the rocket, slightly rotated the electronics board, and tried again. The second time was sort of a charm. I was able to arm the Raven but, upon 'ignition', the motor pressured up very slowly as old motors will. After a sizable chuff the thing lifted off but was marginally stable. This is about the 10th photo of a 5 fps sequence and the motor took about 5-6 seconds to pressure up:

The resultant wiggle sent it NW and way out there. I had a radio tracker signal the whole time and figured everything was intact. After walking out toward the wash for over half an hour and circling about I finally found the transmitter.... just the friggin' transmitter!! It looked like someone had wrenched the thing off the shock cord, left it there, and kept the rocket; or so I initially thought. I ventured out on the original line and asked a camp of moto dudes if they'd seen anything. One fella seemingly sketchily answered "With a green 'chute?" Yes I answered to which he replied "Oh it's back from where you came about a quarter mile out." His answer didn't sit right with me but what was I gonna do? Ask to search their motor home? I bit my tongue and walked back toward the launch site only to find the rocket about 30 feet east of where I'd found the transmitter. I immediately felt guilty about my suspicions so I need to offer the benefit of the doubt in the future.n Here's roughly where I found it:

OK so the payload section and booster were still mated but the nosecone was off and the Kevlar™ cord had ripped through the payload tube about 1.5". Man that aramid fiber is tough!!

As I walked I pondered failure analysis... The apogee charge had blown but the motor and delay had already burned up so the delay hole in the motor must have vented too much of the gas and failed to pop the payload section off. As the rocket came in ballistic the main popped but I had only loosly knotted the 'chute lines the shock cord (no knot on the cord itself). So the parachute, mounted above the taped-on radio beacon transmitter, slipped up the cord, stripped off the transmitter, zippered the payload section, then promptly shredded off. As I walked back I even found the 'chute!:

I'm constantly destroying those TopFlight 'chutes at every single launch. The Raven survived and here's the flight graph:

Despite the serious flight arc I still attained about 8100' so I'm convinced it would have exceeded 10k were it straight. Also the velocity wasn't too bad at roughly mach 1.5. You can also see the blip after apogee where the charge failed to eject and then where the main ejected at ~800'. I wanted to swap nosecones with an extended design anyway so .38 Spatial will fly again soon. Lessons learned:

• Burn those motors soon after you buy them! Chuffing (motor pressure surge before actual ignition) is dangerous. In the early 80s motors employed progressive thrust curves and weren't nearly as reliable as today's motors. I saw a few rockets chuff, pop off the launch rod, then fire off horizontally into the desert. If a motor is older and you still choose to fly it always use a long launch rod/rail as an insurance policy against chuffing.
• RockSim's CP calculation is way too aggressive hence the metastable liftoff. I'm now relying more on OpenRocket's CP calculation as it's typically between RockSim and Barrowman.
• [Just added] Plug those forward closures!! I'm certain I would have attained apogee ejection were it not for the unintended pressure vent offered by the motor itself.
• In the unlikely event of a similar failure in the future place the transmitter above the parachute connection point or, even better, always tie a knot in the shock cord for parachute attachment. That way if the parachute strips off it won't take anything with it.
• Offer the benefit of the doubt to those sharing the desert with us. I have a bad history with this so I have some trauma to overcome. When I was a kid I flew a Composite Dynamics 29mm F45 motor in my prized AeroRoc. It was a high flight on a windy day and the rocket landed on the side of the highway in the bay area. I ran toward it only to see someone pull over and drive away with it when I still had a quarter mile to run. Damn them! Epic recovery FAIL.