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| K600 Thrust Curve. Taken from Pro38.com. |
The weather was pretty decent, although there were some occasional nasty wind gusts to around 20 mph. The skies were partly cloudy, but there were plenty of "holes" to launch into with clear blue sky. I had done 95% of the preparation for the flight earlier in the week to minimize the stress of the launch day, and ended up launching somewhere around 12:30 in the afternoon.
The launch was perfect. The rocket arced gracefully into the strong west wind exactly as I intended it to, with some help from the angle of the launch rail, which is visible in the photo below. Some observers thought they saw a "wiggle" during the boost. I didn't personally notice it, but you can see it in the smoke trail in the onboard video. The wiggle is actually a series of decaying oscillations due to the fact that the rocket is very "overstable" (Center of gravity far forward relative to center of pressure) that it causes some oscillation about the CG before it settles as airspeed builds over the fins. It's a normal phenomenon but is exacerbated by the overstable nature of the rocket, and by the wind.
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| All set for launch. You can see the Mobius HD camera "elegantly" taped to the rocket above the middle stripes. One day, I'll have a better method for attaching the camera. |
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| The Data from the SL100 Stratologger Altimeter. Altitude is the smoothed pink line, with the scale on the left (unit is feet). Speed is the red line, with the scale on the right (unit is feet per second). |
Upon reviewing the ascent data, the maximum speed occurred at about 3.5 seconds into the boost (which makes sense, as this is about when the motor burnout occurred) at about 483 mph.
The drogue came out at apogee right on cue and it looked like it would be a perfect recovery. It stayed in sight the entire flight and by the time it descended to about 3000 feet, I was starting to get nervous. It looked like it was heading towards the island of trees to the north. When the main parachute finally came out at 700 feet, it was looking even worse. Not only did the wind change direction suddenly and push the rocket towards the trees, but it was descending so slowly that at one point, it appeared to actually hover and drift horizontally towards the trees. It turns out that this apparent hovering actually happened. The altitude plot shows that at about 120 seconds in, the rocket's descent slowed from about 21 feet per second to almost nothing. It was during this time that it drifted horizontally towards the trees. You can see this in the onboard video as well. I looked at the SL100's raw data and the rocket averaged just 3.5 feet per second for 6 seconds. This occurred at about 225 feet down to 200 feet in altitude. It had caught a thermal at about the worst time and location.
The nose cone descended under its own parachute and landed several seconds before the main part of the rocket, and did so safely on the field right next to the trees.
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| The Nose Cone, Laying Right Next to the Edge of the Woods. |
Unfortunately, the rest of the rocket landed in the edge of the group of trees. It sure was sad to see that bright orange 6 foot parachute disappear into the canopy of the large trees.
Upon reviewing the raw data from the altimeter, the portion of the rocket with the altimeter came to rest at about 46 feet in height.
When we made it to the site of the rocket in the tree, we were at least somewhat relieved that it was in the very edge of the woods, so no hiking was required to get to the trees it was in. However, the good news ended there, as the lowest part of the rocket was about 40 feet up, and none of the trees involved looked climbable for any of us.
When we were about to get back into the truck to go back to the main launch site to try to figure out what to do, we happened to come across a gentleman whose son climbs trees for a living, and who was spending the weekend at the launch to help people like us get their rockets down. We ended up meeting up with "The Grey Squirrel" and he was able to climb the trees and throw a rope over the shock cord. After some tugging, everything came down, with no damage at all (just some marred up paint, or "battle scars!").
So all in all, a perfectly successful first flight after nearly 3 years without flying any rockets. However, another not straightforward recovery for this rocket. (See this post for the adventure with the second flight.)
Maybe the rocket is telling me to stick with low altitude flights... or maybe not. We will see. I'm glad to have it back and look forward to flying it again.
Thanks to everyone who was there with me to help with the launch and recovery! Below are some of my favorite screen captures from the onboard video.
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| A clear shot of the 9 acre island of trees in the 1000+ acre field. |
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| This is nice view of the "Y" of Keuka Lake, with Seneca Lake in the background. For reference, Seneca Lake is about 13 miles away from the field. |
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| Drogue Charge |
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| Drogue Parachute |
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| A Shot of the Booster During Descent |
Update on 6/28/17: The following pictures were provided by a friend. Thanks Mike!
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| Fitting the Nose Cone |
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| Inserting the Shear Pins |
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| Filling Out the Flight Card |
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| Mike with the Rocket |
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| Clare and I with the Rocket |
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| Weighing at the RSO (Range Safety Officer) Station. Weight was 17.5 lbs. |
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| Walking Towards the Pads |
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| About to Talk to the Pad Manager |
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| Getting Ready to Climb the Ladder to Arm Electronics. |
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| Electronics Armed. Ready to Install the Igniter. |
