Test flight successful on propulsion-controlled aircraft—phase II funded
On July 19, 1989, a fault in the tail-mounted engine of United Airlines DC-10 Flight 232 punctured all three hydraulic system lines, resulting in the flight crew losing control of the aircraft. Dennis E. Fitch, an off-duty United Airlines DC-10 flight instructor, happened to be a passenger on the flight and offered his assistance. Fitch took over control of the throttles and with one in each hand was able to use thrust to make rough steering adjustments and land the airplane.
United Airlines DC-10 Flight 232 crash-landed on a runway in Sioux City, Iowa. Of the 296 passengers and crew on board, 111 died in the accident and 185 survived. Despite the large number of fatalities, the event has been touted as successful because of the large number of survivors, the way the crew handled the emergency, and finding a way to land the aircraft using the throttles rather than conventional controls. As is sometimes the case, tragic incidents like United Airlines DC-10 Flight 232 can spawn an interest in creating additional safeguards and protocols, and even new research.
Phillip Ansell, assistant professor in the Department of Aerospace Engineering at the University of Illinois was partially inspired by Fitch’s use of thrust to steer UA Flight 232 and is researching ways to design aircraft with the capability. He just completed phase one of a NASA-funded project. He recently learned NASA wants to see more and is providing more substantial funding for phase two over the next two years.
Ansell explained the basic aerodynamics at play. “Pilots move the surfaces at the trailing edge of the wing to modify the aerodynamic performance of that section, which in turn allows them to move the orientation of the aircraft. Ordinarily, when pilots lose control of these surfaces the flight crew can no longer predictably place the aircraft into a desired orientation, which can have catastrophic consequences. Using the thrust allowed Fitch to stabilize the pitching characteristics of the aircraft and direct it for an emergency landing at the Sioux Gateway Airport in Sioux City, Iowa.
“If we can figure out how to control the aircraft using propulsion instead of traditional aircraft surfaces, we can potentially eliminate heavy surfaces like the tail and effectively get yaw stability instead from modulating the thrust produced by the fans.”
In phase one of the NASA Small Business Technology Transfer project Ansell and Associate Professor Timothy Bretl, who is co-principal investigator on the project, collaborated with Empirical Systems Aerospace, Inc. in Pismo Beach, California on product development to create the first ever fixed-wing distributed electrical propulsion vehicle. The research team has named the vehicle the Aircraft for Distributed Electric Propulsion Throttle-based Flight Control (ADEPT-FC).
Phase one of the project resulted in a successful test flight, which Ansell said, “went off without a hitch.”
“It’s an electric remote control aircraft, but so is any hobbyist remote-controlled airplane,” Ansell said. “The novelty that we’ve introduced is that we’ve taken the normal single propeller off of the nose of the aircraft, built up new wings, and installed eight electric ducted fans that stretch across the span of the airplane.”
Ansell said the project has generated a lot of interest from students and people outside of the university.
“The first phase required us to work quite rapidly and with a limited budget to prove out the initial concept,” Ansell said. “This next phase comes with greater funding for the next two years. The funding will pay graduate research assistant appointments as well as some hardware. We’ll build wind tunnel models and make additional modifications to our flight vehicle.”