Can active control help tiltrotor aircraft fly faster?

04 September 2023

Although concepts began in the 1940s, vertical take-off and landing (VTOL) aircraft is envisioned for the future. While models like the V-22 Osprey and the AW609 are in operation today, forecasts predict that electric VTOL aircraft will be operating in our skies within 10 years, as taxis and delivery vehicles.

The advantage of the fixed-wing VTOL aircraft, commonly referred to as a tiltrotor, is that it can be launched from an area as compact as a building roof – much like a helicopter – yet its conventional aeroplane wings enable it to reach high speeds.

A challenge to tiltrotor aircraft design is the phenomenon of whirl flutter – an instability that occurs via elastically mounted propeller rotors, causing the entire wing-rotor system to vibrate. This kicks in when a critical speed, specific to the design of each aircraft, is reached. Beyond this, whirl flutter can create vibrations strong enough to shake the wing apart.

Current tiltrotors typically use thick wing sections to increase the rigidity of the wing-rotor system and push whirl flutter to higher critical speeds. This, however, comes with the cost of increased structural weight, and higher aerodynamic drag, requiring more power to lift the aircraft in helicopter mode and overcome aerodynamic drag in aircraft mode.

Read the full article in DPA's September issue