Avery had always dreamed of building an aircraft, so when other students in the USRI wanted to become more involved in meteorological sampling the timing was right. “I’ve lived in Oklahoma all my life, and tornadoes have always been a part of life,” says Avery. “This was a great opportunity to build an aircraft with a purpose.”
Located in the heart of Tornado Alley in the sweeping plains of the United States, Oklahoma averaged 60 tornadoes a year between 2005 and 2014, according to the NOAA. The ultimate goal of the UAVs built by Jacob’s team is to improve understanding of weather phenomenon, particularly severe weather such as thunderstorms and tornados, by providing measurements of thermodynamic parameters and using those to enhance meteorological forecasting models and improve forecast accuracy and warning times.
To collect data, the UAV needs to be both light weight and sturdy, so composites are an ideal material. “Without composites, the aircraft would not be able to withstand the severe environment of a thunderstorm,” says Jacob.
MARIA is made primarily from epoxy resin reinforced with 3-ounce woven E-glass and 3.5-ounce woven carbon fiber or other high-performance fibers in spots requiring extra strength. The wing skin has four layers – fiberglass, 2-ounce aramid fibers, 1/8-inch vinyl foam and another layer of fiberglass. The fuselage skin has the same construction, but uses carbon fiber in place of the aramid. It also features an extra layer in high stress areas, such as the small diameter areas of the empennage. In addition, the UAV has 4.7-ounce layers of carbon fiber in the C-channel as the main support for the wing.
Fabricated via vacuum bagging, MARIA weighs 12 pounds unloaded and 35 pounds with sensors – a mix of off-the-shelf and custom ones. While the UAV has done test flights, it hasn’t yet flown during a tornado. It currently takes several hours to prepare for flight, which is not conducive to chasing fast-developing tornados. However, MARIA and other UAVs fabricated by Jacob’s team have flown successfully in storms.
The work done by the aerospace engineers at Oklahoma State University has garnered the attention of meteorologists at the National Weather Service, National Severe Storms Laboratory and other institutions, who hope to use the data collected to learn more about weather and track weather patterns. Ideally, more insight will lead to better tornado models and more accurate tornado warnings. Avery also has fabricated a second composite UAV for icing studies which will begin next spring.