The Condor (Mark I) was June Sky’s first attempt at an autonomous unmanned ariel vehicle (UAV). The premise behind the build was to design and construct a glider that could sustain autonomous flight for up to 50 miles when dropped from a weather balloon payload above 100,000 feet. Hunter was tasked with designing and manufacturing the glider, while Rohan worked on telemetry and the autopilot system.
A lot of planning went into the initial design, however many iterations were still included in the final design. Hunter began with determining a compact, high-lift, high-drag design that could be manufactured with enough strength to endure the high winds speeds in the upper atmosphere. He settled on a single wing shape with a airfoil similar to that of a hang glider.
The key here was finding a design that had a lot of lift and a high drag factor. Since the goal of this glider was to be dropped from a high altitude, a large amount of lift would ideally help it out of the initial free fall in the thin-air conditions. The high drag factor would also help keep it from gaining too much speed during the initial drop from the balloon payload. If the wing gained a high enough speed out of the drop, the possibility arrises that it wouldn’t be able to recover from the free fall without shearing its wingtips clean off due to the force of the air resistance during a pull-up maneuver.
This is when Rohan’s autopilot system is supposed to kick in. The system, equipped with a GPS, accelerometer, gyroscope, barometer, and a telemetry module, would be able to know the wing’s speed and orientation and would correct it without putting enough torque on the wing to snap it during maneuvers. The autopilot system’s goal is to make the wing autonomously return to the balloon’s launch point.
There were two main reasons for this experiment: the first being that it was a competition criteria in the Global Space Balloon Challenge. The challenge was to have your payload return to the launch location. The biggest problem that arrises with this is that it is illegal to drop any sort of UAV from a weather balloon in commercial air space. It is also illegal to pilot a UAV above 400 feet of altitude and out of eyesight. While we never actually sent this plane up on a weather balloon payload, the possibility of it happening someday is really an exciting notion.
That leads us to the second reason for trying this experiment: efficiency. Every time we launch a weather balloon, we drive hours to recover it, only to drive hours back home after recovery. Since we launch our balloons in central Illinois, the jet stream is almost always overhead as well, which makes our balloons travel even further east. Having our payload and experiments housed in a UAV that can be dropped from the balloon when it reaches altitude would save us hundreds of dollars in gas, as well as equipment. We try to reuse payload boxes from previous weather balloon flights, but most end up getting damaged on impact. Having a UAV that would land the payload safely to the launch position would ensure the UAV’s reusability for future flights as well as the equipment’s safety.
While this experiment is currently illegal for us to conduct, we hope to try it in the future legally with the FAA or other US defense administrator.