Phoenix, the nation’s first solar-powered unmanned aerial vehicle (UAV), successfully made its first test flight in Taipei yesterday, showing off the results of three years of research and development by a team from the Department of Aerospace Engineering of Tamkang University.
The aircraft, which weighs about 9.3kg, has solar arrays (a group of solar panels) attached to its wings that are 3.7m long and cover 65 percent of the wing surface. The solar panels, which operate at 18 percent efficiency, cannot produce sufficient energy to power the drone, so two lithium polymer batteries provide the remaining energy needed to keep the aircraft aloft.
Phoenix has not yet been able to store solar energy in fuel cells for use at night.
“The most difficult part of the project is to design and build a system that utilizes as well as maximizes energy,” said Ma Te-ming (馬德明), an associate professor at the department. “We have developed our own software to achieve the best efficiency possible.”
Ma also said Phoenix could harvest all its power from the sun if solar panels that operate at 30 percent efficiency are used. However, the limited funding provided by the university and the National Science Council means that the researchers need to make the most with what funding they have.
“A 3x7cm panel that is 30 percent efficient costs NT$10,000. We can’t afford it. The total amount we spent on solar panels is around NT$30,000,” he said. “The total cost of the drone is around NT$100,000.”
Composed of about 30 students from two aerial engineering laboratories amd led by three academics, including Ma, the university’s team made a couple of test models before Phoenix.
“My job is to develop the solar energy system. It took forever to set up the system. After it was set up, we spent another year running tests,” 25-year-old team member Liang Chun-kang (梁淳剛) said.
Under the midday sun at the His Sheng Remote Control Aircraft Park in New Taipei City’s (新北市) Sinjhuang (新莊) yesterday, the UAV took off on an airstrip as the research team piloted it by remote control. It flew at an average speed of 34km per hour, circled in the sky a few times and made a slightly rough landing that caused minor damage to one of its tires.
The range of the remote control is one to two kilometers, Ma said, adding the aircraft’s slow velocity renders it vulnerable to crosswinds.
The test flight is expected to provide valuable data relating to battery voltage, electric current, flight height, aircraft motions for further development.
The ultimate goal, Ma said, is to make an entirely solar-powered aircraft, with solar panels feeding on batteries that can keep the craft aloft at night or in the rain.
One of the main reasons for developing solar-powered UAVs is to extend aircraft flight times because they can use the sun as an unlimited source of energy, Ma said.
“Because UAVs don’t need human pilots, we want to keep them up in the air as long as possible to carry out operations considered too dangerous for manned aircraft,” he added.
UAVs have a wide range of uses and mission capabilities beyond military purposes. For example, they can be used for search-and-rescue operations, monitoring drug trafficking and detecting pollution, Ma said.