Academy cadets work to patent aeronautic advances

  • Published
  • By Amy Gillentine
  • Office of Research
U.S. AIR FORCE ACADEMY, Colo. --  Back in 2012, Lt. Col. A.J. Rolling, assistant aeronautics professor, challenged cadets: take two ideas and turn them into inventions, with patents pending, by the end of the semester.

The cadets succeeded, and now the current crop of aerospace majors is busy developing prototypes of patent-pending technology on hybrid turboprop/jet aircraft engines.
These projects stand to do more than just aid cadet understanding of engineering: one could potentially save billions in fuel costs across the Air Force while another shortens the operational kill-chain, the time taken from identifying to engaging a specific target, by combining the traits of propeller engine with those of a jet engine.

Progress stalled when Rolling deployed to Afghanistan, but now that he's returned to the Academy, he's focused on turning the ideas into prototypes.

"The distributor ejector engine has the most promise," he said. "It saves at least 50 percent of fuel costs. What aircraft engine company isn't interested in that?"

This engine works by redirecting excess air through the wing, creating more forward-thrust with less fuel, and is quieter than traditional aircraft engines and can also increase flying time for drones, currently constrained by fuel and battery life.

Rolling said traditional aircraft manufacturers would likely be interested in installing the fuel-efficient engine and had briefed aircraft engine maker Pratt & Whitney about his invention.

"They said it was a paradigm shift in engine design," he said. "It changes the entire design system. But it is also practical - it works."

Rolling's design was one of three chosen to compete in the Defense Advanced Research Project Agency's Innovation Challenge, a competition between USAFA, the U.S. Naval Academy and the U.S. Military Academy. A cadet team will present the prototype at DARPA headquarters in Arlington, Va.

Cadets say the experience has taught them important lessons they will take with them as they begin Air Force careers as second lieutenants.

"We had to work together to get it done," said Cadet 1st Class Tyson Rydalch. "There were a lot of issues we had to pay attention to - if we didn't do it right, we had to start over again."

The experience gave cadets a greater appreciation for the senior technicians employed at the Academy, he said.

"We are working with senior technicians with 20 years' experience," Rydalch said. "And we learned a lot from them about how to do things right - if we messed up one little thing, the rest of the system didn't work. We got a lot of guidance from them."

The second invention, the hybrid turboprop/jet engine, has mostly military applications, but could change the way the Defense Department responds to reconnaissance challenges, Rolling said.

The turboprop has propellers as well as a jet engine, allowing an aircraft to loiter over an area - and respond quickly when needed by folding or shedding the propellers and switching to the jet engine.

As senior capstone projects for aeronautics majors, the group hopes to see their engines in flight by the end of the month.

"We know it works from the computations," Rolling said. "And we've tested it in wind tunnels. Now we just have to have it in the air to prove it to everyone else."

Designing the two engines using computational geometry and physics was easy, he said. The hardest part is how to create the prototype - build two brand new engine systems in a single semester.

"Our goal now is to bench test both systems and then to get them in the air someway," Rolling said. "We're working very closely with the mechanical engineering department to create the prototype for next year's capstone seniors to work on moving to the next level."
The engines aren't quite ready for prime time: Rolling says there is still a lot of optimization work to improve performance.

"Aero people don't believe it will work until they see it in fly," he said. "No one will buy it until they see it in the sky."

And that's where the mechanical engineering department's Composites Laboratory comes in. Aero cadets have been working in the composites laboratory to build the plane that will test Rolling's engine. The team created the plane with a 10-foot wingspan from design to manufacturing.

"It's really awesome," says Cadet 1st Class Hannah Wiesneski, a senior cadet majoring in aeronautics who will go to pilot training at Sheppard Air Force Base, Texas, after graduation. "It's something tangible - learning about things in textbooks is one thing, but learning about it by building it yourself - that makes a world of difference."

She and Cadet 1st Class Josh Durbin, also an aeronautics major, have been working in the composite lab - both gave up their final spring break to get the plane flight-ready.
"It's very exciting to see something go from design to actually being able to fly," she said. "We designed it from nothing. And the manufacturing - that's the rewarding part. It will be a major accomplishment to watch it fly."

Not many undergraduates can say they built an airplane in their final months of school, but Wiesneski and Durbin will have something to brag about - and an experience to build on when they enter the operational Air Force.

"It's taught me how my plane actually works," she said. "Other pilots won't understand that. I'll understand the way it's built, why it's built that way."

The aircraft has other purposes as well. Cadets will use it to track beetle-infested trees on Academy grounds this fall. Other researchers will use the plane to drop small gliders with sensors mounted on them around the Academy.

It's rare for a project to have this much collaboration, Durbin said.

"There are some unique aspects to it," he said. "There's strong integration between the engineering mechanics and aerospace. This wouldn't be possible without that collaboration, getting to see how other departments work."