65mm scratch built, H-128

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Feb 3, 2017
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This is my first post here on the forums (the mess of a title kinda reflects, 63 mm, not 65mm), but I wanted to document a build and launch I did earlier this year in January and how its going to relate to later launches I plan. This was not my first HPR launch (it was my 4th), but it was my first rocket I launched more than once, and I'm quite proud of that. It is also proof that I finally learned one of the most important pieces of advice in rocketry:

Take pictures, then launch rocket.

The rocket was built and launched for my college's NASA Student Launch competition team, and is a 2:1 sub-scale of our competition rocket (expect a thread for that after the competition is over). It actually wasn't the first subscale that I attempted. The first one flew with a 54mm body tube in December, and had an otherwise perfect flight except for recovery. We launch with the fellows out at SRA, and the launch location has the unfortunate property of being surrounded by thick Floridian vegetation. Even with a reefed parachute the rocket drifted very far, and wasn't able to be found, even with a "screamer" installed. There doesn't exist many photos of this launch because the team was shorthanded that day.

Learning from mistakes I aimed to relaunch in a months time with some changes made to the design: a larger 63 mm body tube and fins to keep the apogee lower, a smaller parachute, and a RF transmitter. No photos exist of the build itself because of a pretty humorous series of events. Because much of the material for the rocket was unavailable over the winter academic break, I only budgeted a couple of days before the launch date to build the rocket. Then the weather forecast for the launch day came out unfavorable, and we had to move the launch up a day, resulting me to building the rocket in 1/2 a day (thank god for 5 minute epoxy).

Launch day came on January 6th, and the conditions couldn't have been better. Severely clear skies, with 0-5 mph winds, and a pleasant 80f day. I invited out a local photographer for the launch (he photo's much larger rockets) so the launch was well documented. Setup went well, and the rf transmitter and the rk-15 altimeter were installed easily. On the pad we decided we'd better not have to do this again, so we installed a backup altimeter for extra recording redundancy.

The rocket flew brilliantly straight, and reached an apogee of 1900ft ~9 s into the flight. The motor ejection successfully deployed the parachute at ~11 s. OpenRocket had nailed the apogee simulation within 1%, but was 10% off for the time to apogee. At recovery the one hiccup the flight occurred; the nose cone fell off. This was not a serious problem because the electronics were very well wedged into foam, but did give me a bit of a heart attack. The rest of recovery went well, with the rocket drifting down into a relatively clear area of land within sight of the launch site. The RF transmitter was not needed for this flight, but was used on a later launch with the same rocket after winds and a thermal carried it off a bit.

All in all it was my most successful launch to date, and gave me a lot of important experience. All my rockets from now on are going to have an RF transmitter installed for one!

Attached to this post is the pictures of the rocket and the flight, 1 altimeter data graph, and linked below is a video with its flight:
The assembly

On the Pad
DSCN1999 175.jpgrocket_moon.jpgtest_flight_pic_1.jpg

Getting at the data

The OpenRocket file:
View attachment jesse_scaled_jan_1_63mm.ork

the video
Welcome aboard. Nice pics. Every time I see people outside in the sunshine launching rockets, I get jealous, even if I just launched yesterday. :wink:
Glad the flight went so well.
We've had several teams for the NASA SLI at our launches. I'm always amazed at the technology, and engineering that goes into the rockets. Then I see the lack of experience also. Those of us that have been launching for 10 years have a lot of hard earned lessons learned. The SLI students are just getting into launching and don't have that benefit. Unfortunately it can cost dearly sometimes, others, its just a quick lesson.

Hope your launches go well and you don't have to learn any of those lessons the hard way. Pick the brains of the folks at the launches. Most of them are more then happy to lend you their experiences.

Good Luck