Fifth Fullscale Flight
For our fifth fullscale flight, we launched the fullscale rocket to about 4,800 feet. Our goal was to accomplish the 2017 NASA SL challenge, even though we cannot compete in it. The 2017 challenge is to create a device that controls the roll of the rocket to make it spin 720 degrees. Our roll alignment device was perfectly suited for this, with just some small changes to the programming.
On Saturday, September 24th, three of us drove down to the Bayboro Launch Field. After a day of preparation, we launched it on an slightly unstable pad. This caused it to launch at a higher angle than anticipated, and go towards the woods. While the roll control worked (until we ran out of rotation power), it was only able to rotate 520 degrees. The rocket then landed in a mosquito-infested forest, and we had to trek through it to find the rocket. In the end, it was undamaged, and the flight was successful. See below for some videos of the flight:
After a few weeks of hard work repairing and refining the rocket, we were ready to fly again, this time in Camden, SC. The field was smaller than what we were used to with our NC site, so we chose to fly on a slightly less powerful motor: the K805G. This propelled us to an altitude of 3373 feet. Both payloads worked, although the ILD was not completely successful. Videos of the launch and more payload information is below.
Yesterday, we flew our fullscale rocket in Bayboro, NC for the second time, this time with a running roll control device and balloon payload. The rocket, now painted completely black, went up around 4793 feet, under our target of 5280, but it was a windy day and the roll control flywheel was not working perfectly. This time, both cameras worked and the altimeters reported similar figures for apogee. While the balloon payload's connection to the nose cone broke, and the roll control flywheel needs some touch-ups, the flight was successful in that everything essential to a safe flight worked correctly. Below are images and pictures from the launch.
Because our first flight was too high (5498 ft), had a smaller mass, and no ballast or paint, we chose to fly our rocket again with a K1000T motor. This flight was with 12 oz ballast and paint. The mass of the rocket increased to 23.8 lbs. While our simulations predicted 5283 ft for vertical launch with no wind, the actual launch was about 10 mph wind angled a few degrees into the wind, away from the crowd. Apogee was at least 1500 ft into the wind according to our GPS data. The most precise reading for apogee was 4793 ft (due to the significant arc into the wind). In conclusion, the rocket is stable ballasted from 22.6 lb to 23.8 lb. The location of ballast (forward of CG) improves the CG-CP stability margin. Unless there are objections, we intend to fly at Huntsville ballasted to about 23.8 lb.
In addition, the RAD (roll control device) was operational. Communication with the new VESC motor controller was implemented two days before the flight, so we did not have the PID algorithm optimized. We experienced significant oscillation in the roll position. We are working to improve this for the next flight. The roll oscillation is clearly seen in the videos. GPS downlink was working. See flight path below. The balloons disconnected from the nose cone. Possibly a poor knot was used. We are updating their knot tying skills. Lastly, dual deploy recovery worked fine.
More pictures and videos after you click "read more"
This blog will be updated once a week over the course of the 2018-2019 school year, detailing our progress. It will be signed at the end by a member of the team.