Novel active flow control system for improved performance of VTOL aircrafts


Project ID:  2016-66


Technology summary:

The market of Vertical Take-Off and Landing (VTOL) with a CAGR of 19.11% is at its strongest point that will lead the world in several areas such as communications, surveillance, automobile, intelligence, and defense. VTOL Unmanned Aerial Vehicle (UAV) that has ducted-fan are known for superior stationary aerodynamic hovering performances, low-speed flights, precision vertical take-offs, and landing capabilities. However, they encounter loss in aerodynamic performance with increased noise and vibrations, due to flow separations inside the lifting device systems. Though, fan-in-wing (FIW) devices are preferred in several applications due to the advantages of vertical takeoff and high speed forward flight over ducted fans, they suffer from low hover efficiency like ducted fans due to relatively high disk loading. These restrictions have significantly reduced the maximum thrust generated by the system and flight envelope for VTOL aircraft to perform critical aviation operations.


Invention description:

Researchers at the University of Toledo have developed a novel active flow control system to improve the aerodynamic characteristics of lifting devices such as FIW and ducted fan systems to enhance the system thrust and efficiency while reducing the power consumption of the systems. The novel system incorporates air injection in the duct inlet section and air suction in the duct diffuser section to modify the aerodynamic flow field within the lifting system. The novel system is capable of activating injection and suction in situations when extra system thrusts are needed, but are turned off in normal operating conditions. The novel active flow control system achieved up to 55% increase in maximum thrust without suffering the peak efficiency loss, thus enhancing the aerodynamic performance of the VTOL aircrafts.



Vertical Takeoff and Landing (VTOL) aircraft, Unmanned Aerial Vehicle (UAV).



•       The maximum thrust of the FIW system increased by 25-55% at variable fan rotational speeds using the novel active flow control system while maintaining the hover efficiency at high levels.

•       Enhanced operating efficiency and thrust level of the system by increasing the circulation and duct mass flow rate in the fan-in-wing or ducted fan system.

•       Redirecting the suction mass flow back to the duct exit section to form a zero-net mass flow active control system.

•       The novel system improves the overall aerodynamic performance of the device in hover, forward, and transient flight.



1.       Sheng, Chunhua, et al. “Numerical Investigations of Fan-In-Wing Aerodynamic Performance with Active Flow Control.” AIAA AVIATION Forum, 10 June 2016,

2.       Sheng, Chunhua, et al. “Numerical Investigation of Active Flow Control for Fan-In-Wing Configuration in Forward Flight.”  AIAA AVIATION Forum, 2 June 2017,


IP Status: Patent Pending


Patent Information:
For Information, Contact:
Stephen Snider
AVP Tech Transfer
The University of Toledo
419 530 6225
Chunhua Sheng
Qiuying Zhao
Active Flow Control (AFC)
Ducted Fans
Fan-in-Wing (FIW)
Unmanned Aerial Vehicle (UAV)
Vertical Take-Off and Landing (VTOL)