Tuesday, July 24, 2012

The "We" (shortened Weasel)

Well I got sick of seeing the remains (just the booster and nose cone) of the Weasel's shred on my workbench so I decided to try to make it fly again.

After playing around in Rocksim with motor weight vs. required nose weight, I figured out that 1 and 2 grain 29mm motors should fly it nicely...with 10 ounces of nose weight to keep it stable.

I put 9 ounces of BB's into the nose cone and poured 1 oz of West Systems epoxy on top to sink into it them and hold everything in place.

With a 38-29mm motor adapter in place, the only way to still fit a parachute and Kevlar shock cord was to use the empty space still left in the nose cone. I used a dowel to retain the shock cord in the nose.



Here's the finished We. I expect about 700 feet or so on a Pro29 F59.

Tuesday, July 17, 2012

LDRS 31: The Science Channel & Kari Byron

The Science Channel was at LDRS 31. They primarily focus on the "oddrocs" (the weird stuff). The show that is aired eventually is hosted by Kari Byron of Mythbusters, so she was there on Sunday and Monday of the launch. Clare and I were fortunate enough to meet her and I got her signature on my M motor case. I also took a few pictures of when they were actually shooting for the show.








LDRS 31: Others' Rockets

There were many many many large rockets, and especially weird rockets. Probably the weirdest was the real working snowmobile that flew on an N10000. It went up about 100 feet and flipped over on itself and crashed. This is what was left.








The Black 5 was one of the last flights of LDRS 31. It blew up catastrophically at LDRS 28 and it was back. This time it flew on a bunch of experimental motors. I may be wrong but I believe it was a central N motor, 2 M motors, and 2 L motors. It shredded 1 fin on the way up but maintained a straight up boost and recovered successfully.




This V2 was the largest rocket I've ever seen launch, and the heaviest rocket at the launch. It weighed 505 pounds on the pad. It flew on a central O motor and 2 N motors to about 8000 feet. The main parachutes didn't fully open but as you can see in my pictures, it survived unscathed I believe.





LDRS 31: My Flights

LDRS 31 was at the local flying field for me this year in Potter, NY and spanned July 12th through 16th. I was there on all 5 days, flying rockets on the first 4. Though I only launched 5 times, it was the most total impulse for me at one launch. The weather was absolutely perfect: clear skies and light winds (though it was uncomfortably hot every day but it's supposed to be that way for a rocket launch).

LDRS is such a busy event (with 269 fliers registered, and many of which were way cooler flights than mine), that I did not focus on collecting pictures or videos of my launches. That being said, all I really have is some data from 3 flights with my new Perfectlfite altimeters and 1 onboard video from Positive Ascent.

So here's the recap of my launches day by day:
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Thursday July 12th, 2012:

I launched my 29mm Minimum Diameter rocket on the I224 Classic motor. It was about as disappointing as one (especially me) would expect....

Here's what happened:

It took off extremely hard as expected but immediately corkscrewed violently (just like what ended the Super Weasel a couple months ago). At about 1000 feet it finally broke into two - the booster with motor casing arcing over gracefully to the east according to some witnesses, and the top half with the tracker and altimeter falling surprisingly near the pad where it took off. It took a while to track the signal to finally find the top half of the rocket. The booster is still lost but it wasn't a big deal as that motor hardware was only around $50 and I replaced it right away.

Here's where it got more interesting. When I went to retrieve my launch pad (the custom tower I built for this rocket) I was incredibly surprised to find that it was in 4 pieces on the ground.

Here are a few post-shred pictures of what's left:





Given the flight path and condition of the pad, I determined that the pad either failed instantly, causing the corkscrew, or the rocket caught on the pad, ripping it to pieces and causing the corkscrew. The corkscrewing followed by a shred produced nothing but erroneous data on the altimeter so no velocity or altitude data was taken from the flight.

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Friday July 13th, 2012:

After a not-unexpected, but still disappointing failure on Thursday, I launched a couple more conventional rockets on Friday.

First up was my X-Calibur, which was my first high power rocket and is somewhere in the vicinity of 12 years and 30 flights old. Since I now have a reliable tracking system, I put in way more motor than I previously would have. I selected an I243 White motor from CTI. It was a perfect straight and fast boost to about 560 miles per hour. The altimeter recorded 4300 feet. Even with single deployment, the rocket came almost straight down a couple hundred yards away for an easy recovery. 

Here's the plot that I made from the data from the Pnut altimeter:



After the success from the X-Calibur, I decided to go a little bigger. I loaded up a CTI K360 White motor into my Eclipse. At 1281 Newton-seconds, this is the most total impulse that will fit into that rocket. The motor provided a beautiful straight boost and the Eclipse had a picture perfect launch to 5401 feet. 

When Clare and I were walking back from recovering the Eclipse, people from the Science/Discovery channel (they were there the whole launch too, more on that later) were filming us and had us sign release forms just in case they decide to use that shot on the TV special of LDRS.
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Saturday July 14th, 2012:
This is the busiest day of LDRS, and I decided to launch Positive Ascent on the bigger of the 2 motors I had prepped for its 10th flight. With clear skies and low winds there was no reason not to. I flew without the camera bay on a 5 grain M1670 Blue Streak. It was an absolutely perfect straight up launch. We followed it until the drogue charges separated it at apogee. It wasn't until the main popped at 900 feet a couple minutes later that we saw it right again. It was coming in hard right behind the row of trees behind the flight line. The pilot chute was open but the deployment bag for the main parachute was tangled enough where the chute wasn't releasing. After what seemed like an eternity, the main opened suddenly with only about 400 feet left with the pilot chute slightly tangled up in the main's lines still. The rocket landed softly in a field just on the other side of the treeline near the parking area. The rocket had reached an altitude of 9900 feet, a few hundred feet higher than expected and just under mach 1.



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Sunday July 15th, 2012:
Sunday started with a few light rain showers but I sat and prepped Positive Ascent for a lower 11th flight anyway. Sure enough the rain passed, the clouds passed, and for the 4th day we had perfect rocket weather. This time, Positive Ascent was ready to go with the camera bay installed. It flew on a 54mm L805 White motor. It was another perfectly straight up flight and recovered perfectly in the field this time. It reached 3300 feet so the video isn't that spectacular, but it is still cool.












Tuesday, July 10, 2012

Positive Ascent's New Paint Scheme

Well I was caught off guard by how much work it was to re-finish Positive Ascent. It took a total of around 10 hours of sanding just to get through the cleat coat and some of the original paint to provide a decent starting surface. After that, I did several coats of primer on the whole rocket and wood filler on the low spots which meant many more hours of sanding. I would estimate that I spent about 40 hours total on the re-finish.

However, it is finished just before LDRS 31 and I'm fairly happy with how it came out. I went with basically the same color scheme except for True Blue instead of Grass Green. I also made the points on the booster a bit longer.

The first time I painted Positive Ascent, I only had regular masking tape which resulted in sloppy lines. This time I used true fine edge modeler's tape so the masked lines are for the most part much crisper than before.




The camera bay was never fiberglassed which is why it is so uneven compared to the rest of the rocket.

Wood filler in the spirals of the camera bay.

Electronics bay getting its fresh paint.

All primed and the white was just painted. 

Finished without camera bay.


With camera bay.