Surveillance planes searching for wildfires, missing persons or military targets need as much time in the air as they can get, said Russell Westphal, a mechanical engineering professor. So aircraft companies seek to maximize aerodynamic performance, making their planes use less fuel.
“That translates to more time in the air,” Westphal said.
For a decade, Westphal has worked with students on his creation, the Boundary Layer Data System (BLDS), which employs small, self-contained, autonomous instruments to help aircraft companies measure the aerodynamics of their planes. And, as Westphal seeks funding to modernize his creation, the BLDS is in the midst of one of its busiest years, having completed three flight test programs in 2018.
On one of those, the BLDS was one of some 40 technologies evaluated as part of Boeing’s 2018 EcoDemonstrator flight test program, which employed a new 777 freighter aircraft built for FedEx.
“The 777 flights represent the biggest challenge that BLDS has yet taken on to date,” Westphal said. “The flights set numerous BLDS records and firsts, solidifying the unique BLDS approach as an established flight test paradigm.”
Ten years ago, the idea for the BLDS came to Westphal when approached by Northrop Grumman. Aircraft companies make predictions on aerodynamics, but they need something to test those predictions. So Westphal came up with the BLDS, which specifically measures near-surface airflow within the boundary layer of a full-scale aircraft during flight. (The boundary layer is a thin layer of air immediately above the surface that is responsible for friction – also known as drag – of an object moving through air.)
“The idea I had for quite a while was to have a cigarette pack-sized instrument,” Westpal said.
Weighing less than a pound, the BLDS could be attached on planes with removable adhesives.
“BLDS instruments have been attached on wing surfaces, the vertical tail, or the fuselage, to make measurements on those surfaces,” he said.
Data gathered from those devices can be used to validate and improve engineering tools as well as provide research data on issues such as the influence of manufacturing imperfections – and even insect strikes — on the flow. But the main goal is to reduce drag.
“Companies are seeking to improve performance and especially to reduce fuel burn,” Westphal said.
The project was originally created as a vehicle to involve students in unique and exciting engineering work, Westphal said. Each year, between 6-8 students work on the BLDS.
Over the summer, Robseth Taas, an aerospace engineering student, worked on the project, examining several types of battery cells that are potential new power sources for the BLDS.
“I put the batteries through different conditions and measured their responses in order to gauge their viability,” he said.
Several students who worked on the project in the past have gone on to work in the aerospace industry.
Brittany Kinkade, who earned a masters degree in mechanical engineering, worked on the BLDS for two years, during which her interest in aerospace engineering grew. Now she works as a wind tunnel test engineer for an aerospace company in Los Angeles.
“Dr. Westphal’s program really opened my eyes to the wind tunnel testing realm, and I learned so much through him and other students involved that I wouldn’t have normally learned through my coursework,” she said.
Ryan Murphy, who worked on the project from 2014-2015, still keeps in touch with Westphal and some of the other BLDS students and works as an aerospace structures engineer for the United States Air Force.
“Working with Dr. Westphal prepared me for my current position by strengthening my ability to innovate and push the edge of the envelope,” he said.
While the design for the BLDS froze in 2009, technology has advanced in microcontrollers, wireless communications, low-power electronics and digital sensors.
“So the challenge now is to exploit the advantages that these advances enable to create an all-new next generation BLDS,” Westphal said.
His team has assembled a proof-of-concept prototype of the next generation of BLDS – called BLDS-M (modular) and is seeking support to build out the concept in a collaboration with the Cal Poly Autonomous Flight Lab.
“The compact, modular nature of the next-gen BLDS devices can enable flight test measurements on small unmanned aircraft systems (UAS) that are impractical today, enhancing the performance of future UAS,” said Aaron Drake, an aerospace engineering professor, who directs the Autonomous Flight Lab. “Also, the availability of UAS here at Cal Poly will allow more rapid testing of BLDS devices in flight, leading to more opportunities to involve students in exciting engineering work and accelerating the development of the next-gen BLDS.”