Feasibility of Hovering Aircraft Demonstrated with 3D Printing

While helicopters are uniquely capable of performing vertical takeoffs and landings, they do so while sacrificing the speeds associated with airplanes. For this reason, the Defense Advanced Research Projects Agency (DARPA) launched a program devoted entirely to constructing the next generation of aircraft that avoid the long runways associated with sending jets into the sky. DARPA’S Vertical Takeoff and Landing Experimental Plane (VTOL X-Plane) project, initiated in 2013, is steadily seeing progress, as its prime contractor has been awarded and has begun work on building the VTOL X-Plane concept. On April 18, the chosen contractor, Aurora Flight Sciences, announced the successful take-off and landing of a 3D-printed, subscale version of their LightningStrike plane concept.

The wings and canard of the scale model of the LightningStrike aircraft were 3D printed. (Image courtesy of Aurora Flight Sciences.)

After receiving the Phase II contract from DARPA on March 3, Aurora began testing its LightningStrike concept by constructing a 20 percent–scale flight model. Weighing only 325 lbs, the subscale aircraft features a wing and canard tail system made up of carbon fiber and 3D-printed thermoplastics. The use of 3D printing allowed the team to create a highly complex model, in terms of structural and aerodynamic surfaces, while reducing the weight as much as possible. Upon completing the model, Aurora tested the aircraft’s flying capabilities through remote control, successfully validating the ability of the model to perform takeoff, hover and landing functions in the presence of DARPA officials.

The scale model of the LightningStrike aircraft successfully demonstrated the ability to perform a vertical takeoff and landing, as well as hovering. (Image courtesy of Aurora Flight Sciences.)

In addition to the partially 3D-printed components, the model demonstrated the use of Aurora’s distributed hybrid-electric propulsion system, which relies on a synchronous electric-drive platform. The full-scale aircraft would see a Rolls-Royce AE 1107C turboshaft engine power three Honeywell generators and 24 ducted fans mounted along the wings and canard horizontal stabilizer system. These fans are combined with an electric drive system that allows for the hovering efficiency and speed sought by the DARPA project. According to Aurora, this is the first aircraft in aviation history to have proven the feasibility of such a propulsion system.

Aurora Chief Technology Officer Tom Clancy spoke to the success of the testing by saying, “The successful subscale aircraft flight was an important and exciting step for Aurora and our customer. Our design’s distributed electric propulsion system involves breaking new ground with a flight control system requiring a complex set of control effectors. This first flight is an important initial confirmation that both the flight controls and aerodynamic design are aligning with our design predictions.”

This artist’s concept depicts the ultimate LightningStrike design. (Image courtesy of Aurora Flight Sciences.)

With the validation of the model’s flying capabilities, Aurora will work with its partners, Rolls-Royce and Honeywell International, to construct the full-scale LightningStrike aircraft over the course of the next 24 months. The final aircraft will ideally reach speeds of 300 to 400 knots and a hovering efficiency that is 60 to 75 percent better than existing VTOL aircraft. The next year will see Aurora work toward validating the flight control system and the configuration of the full-scale version of the LightningStrike aircraft, laying the groundwork for the plane’s first flight tests scheduled for 2018. So, that’s five years from project inception to full-scale aircraft. Given the usual development time for aircraft, this is indeed an example of rapid prototyping at its finest! Thank you 3D printing!