Aurora Flight Sciences, a subsidiary of Boeing, is currently developing the X-65, a technology demonstrator aircraft, as part of the US Defense Advanced Research Projects Agency’s (DARPA) Control of Revolutionary Aircraft with Novel Effectors (CRANE) program. This aircraft aims to showcase the capabilities of active flow control (AFC) as a key design element, with the potential to greatly transform the future of aircraft design and enhance overall performance.

Aurora Flight Sciences initiated the development of an experimental X-plane in November 2020 as part of the DARPA’s CRANE programme. This endeavor, known as Phase 0, entailed collaborating with Boeing and the University of Arizona to establish tools and methodologies for integrating AFC into the early stages of aircraft design.

Following this initial phase, the subsequent stage focused on the preliminary design of the X-plane demonstrator, aiming to showcase the practical advantages of AFC technology.In August 2021, the company progressed to Phase 1 of the programme, which encompassed the development of system requirements, initial design efforts, software creation, and initial airworthiness evaluations. As part of Phase 1, wind tunnel testing took place in San Diego, California, US, in May 2022. These tests laid a strong foundation for the development of flight control laws centered around AFC.

In December 2022, the DARPA allocated funds for the detailed engineering design of a full-scale X-plane, bringing the aircraft closer to flight readiness. This funding is part of Phase 2, which also includes the option to construct and fly the aircraft in subsequent phases.In January 2024, Aurora Flight Sciences was selected by the DARPA to construct a full-scale X-plane for Phase 3 of the CRANE programme. This phase will demonstrate the effectiveness of AFC actuators as the primary means of flight control. During this phase, an X-plane will be created without conventional moving control surfaces. The primary focus of the aircraft’s design will revolve around an AFC system, which will direct pressurized air to effectors that are embedded in all the flying surfaces.

To manipulate the airflow over the aircraft’s surface, jets of air will be utilized, with AFC effectors taking charge of controlling the roll, pitch, and yaw. By eliminating the need for external moving parts, the weight and complexity of the aircraft are expected to be reduced, ultimately leading to enhanced performance.The X-65, designed as a modular testbed, will showcase interchangeable outboard wings and AFC effectors, enabling the testing of various AFC designs.To gain a deeper understanding of AFC’s potential impact on future aircraft, sensors will continuously monitor the performance of AFC effectors in comparison to traditional control mechanisms.

The uncrewed full-scale prototype will possess a wingspan measuring 30ft and a total weight of 7,000lb. It will possess the capability to achieve speeds of up to Mach 0.7. To ensure the flight test outcomes are directly applicable to practical aircraft design, the dimensions and velocity of the prototype will resemble those of a military trainer aircraft. The X-65’s unique wing shape, resembling a diamond, will facilitate extensive learning about advanced flight control in real-world testing scenarios. Moreover, the X-65’s modular platform design will enable it to function as a testing asset for not only the CRANE program but also for DARPA and other agencies. Version 1: The X-65 aircraft has been specifically designed to assess and showcase the diverse capabilities of AFC across different effects, such as tactical flight control and performance enhancement. To establish a performance benchmark, the aircraft will initially be fitted with conventional flaps and rudders alongside AFC effectors. As the testing progresses, the reliance on moving surfaces will be minimized, with subsequent tests increasingly relying on AFC effectors.