In order to ensure the continued existence of our club, we are emphasizing underclassman involvement. In order to become a certified level two member of the Tripoli Rocketry Association, one must launch and successfully land an H class motor as well as an I or J class motor. In addition to the successful flights, the applicant must pass a written exam to prove their knowledge of safety protocols and the basic physics behind a rocket launch.
Each applicant must build their own certification rocket. Last year, Adam Vogel built a single rocket capable of flying both an H and J motor. We will conduct the same process this year. The materials and equipment necessary to roll our own fiberglass tubes are not warranted at this time. We will buy the fiberglass components and assemble the rest ourselves. Last year, Adam Vogel used two single-use motors to certify. This year, the team will be using two reusable anodized aluminum motors.
Rocket Motor Design and Fabrication
The reason for using more expensive reusable motors is that we will be able to use those same motor tubes to preform static tests and fly our research motors. There are many different formulas for making rocket motors. Some of the more popular ones include potassium nitrate and sugar, commonly called ‘rocket candy.’ Rocket candy typically burns around 2,500 degrees Fahrenheit. The fuel we are designing will burn from 7,000-10,000 degrees Fahrenheit. Due to the volatile nature of chemicals involved, supervision is required at every step. A Lieutenant Colonel in the Air Force checks our formulas before we even start mixing. He then observes the mixing process along with a chemistry professor to ensure everything is done safely.
We have ordered all of the necessary chemicals and prepared the machinery necessary for mixing. Since this is a university web page, I am unsure how detailed I am allowed to be. If all goes according to plan, we should have our first motors mixed and ready before or right after Christmas break. Tripoli does not allow research motors to be used for certification so we had to purchase commercial reloads that fit in our motors.
Perhaps the most complex project we have this year is designing some mechanism for accurately delivering a golf ball to the ground from 8,000 feet. Originally, we planned to design a quadcopter with hinged arms that would eject at apogee and be able to autonomously fly to the ground. We recently tested a simplified version of that drone with negative results. After a brief second of flight, the drone flipped onto its back and crashed into the ground damaging the $150 flight controller beyond repair.
We thought autonomy was necessary because we likely won’t have visual contact with our vehicle. If we can see what the vehicle sees, however, then we don’t necessarily need to see it from the ground. First-Person View (FPV) cameras are relatively small and can be mounted anywhere on a vehicle. Even with a low resolution camera we would still be able to discern ground from sky. The problem with FPV alone is that last year when we launched, there was snow on the ground. A high resolution camera would be of no use if everything is white. We still need to have a rough idea of where our drone is. GPS transmitters solve that problem. One of our prizes for earning second place in the Argonia Cup was a GPS transmitter. With some minor modifications to ensure an adequate transmission rate, the GPS system we already have should work fine.
We are still deciding whether or not to switch from a quadcopter to a powered glider. There are benefits to each but as far as simplicity is concerned, it seems like a glider would be best. There are RC and FPV systems with more than enough range, so while we might lose autonomy and a few yards of accuracy, we should be able to complete our mission.