Daiju Uehara and Young-Joon Choi
Aerospace engineering graduate students Daiju Uehara (left) and Young-Joon Choi (right)

Associate Professor Jayant Sirohi and aerospace engineering graduate students, Young-Joon Choi and Daiju Uehara, won Best Paper awards for their submissions to the 6th Asian-Australian Rotorcraft Forum on November 7 in Kanazawa, Japan. The forum is sponsored by the American Helicopter Society, an organization that has encouraged the advancement of vertical flight technology for more than 70 years.

Choi and Sirohi’s paper titled, “Separation Control using Rail Plasma Actuator on a VR-12 Airfoil,” details Choi’s engineering of a new device, the railgun based plasma actuator (RailPAc). The device is designed to influence the airflow over helicopter blades and increase the weight of what a helicopter can lift.

“We have demonstrated for the first time the successful manipulation of the airflow with a RailPAc and measured approximately 40% increase in lift compared to a conventional rotor blade design,” Choi said. “The result presented matured a novel concept that can ascribe revolutionary performance to future helicopters."

Uehara and Sirohi’s paper also focused on improving helicopter designs. His paper, titled, “Deformation Measurement and Modal Identification of an Extremely Flexible Rotor Blade,” examines a more efficient way to measure shape changes of a rotor blade while it is spinning.

flexible rotor stand
Jayant Sirohi and his research team used this flexible rotor stand to conduct experiments that could improve helicopter blade design.

Traditionally, blade motion was measured by applying sensors to the blade, which often changes the structural properties of the blades or is ineffective due to strong centrifugal forces acting on the sensors. By painting dots on each blade and photographing them in motion with a high-speed camera, Uehara minimizes these drawbacks without having to apply sensors.

“We successfully applied the technique to an extremely flexible helicopter rotor blade, whose shape change cannot be measured by conventional measurement technique but by our approach,” Uehara said. “This study could lead us to a further understanding of physics behind such a complicated helicopter rotor blade’s dynamics.”

The research outlined by Choi and Uehara could improve helicopter designs and increase efficiency during natural disasters, emergency situations and military missions.