DARPA has awarded Aurora Flight Sciences a Phase 2 contract for its CRANE (Control of Revolutionary Aircraft with New Effectors) program following wind tunnel testing of a small-scale X-plane that uses compressed air bursts in place of control surfaces. bottom.
Elevators, ailerons, rudders, flaps, flaperons, stabilizers… from the Wright Brothers’ Flyer to the F-35, nearly every airplane ever built used moving control surfaces to subtly control the air plane in flight. It has changed shape and changed aerodynamic pressure and force. Adjust pitch, yaw and roll.
DARPA’s CRANE program is not. Its goal is to build “an X-plane demonstrator that can fly without traditional locomotion controls outside the wings and tail.” why? Agencies want to eliminate the weight and mechanical complexity associated with moving control surfaces. You want to reduce drag for efficiency, you want to run thicker wings for structural reasons and retain more fuel, you want to simplify the high-lift system, improve overall performance and increase the angle of attack.
aurora flight science
This aircraft has no external moving parts. Instead, it is flown using active flow control (AFC), using a series of nozzle arrays along the wing connected to a pressurized air system to blow controlled bursts of air, adjusting air pressure and aircraft You can directly change the flow around you. It destroys the boundary layer between air streams moving at different velocities. In effect, it is designed to create a virtual control surface out of compressed air.
A similar AFC program underway at NATO’s science and technology agency had a small model flown about five years ago, but Aurora Flight Sciences has worked primarily in wind tunnels so far. In the first phase of model testing, the company built a 25% scale prototype aircraft with 11 movable conventional control surfaces and 14 AFC banks fed by eight individually controllable air supply channels. Did. Over 14,000 data points were collected during four weeks of wind tunnel testing.
Phase 2 of the project is now underway, with Aurora beginning the detailed engineering design of a full-scale unmanned AFC test aircraft with a wingspan of 30 feet (9 m) and gross weight of 7,000 pounds (3,175 kg). Ability to fly at speeds up to Mach 0.7 (537 mph, 864 km/h). It is a modular machine, with interchangeable wings for testing different wing shapes and sweeps, and the ability to interchange entire AFC effector nozzle banks for testing different designs.
aurora flight science
If DARPA chooses the option for Phase 3 of this project, Aurora will build it and begin flight testing sometime in 2025.
“Over the past decades, the active flow control community has made great strides in enabling active flow control technology to be integrated into advanced aircraft. We are confident in completing design and flight testing of the demonstration aircraft,” said Richard Wlezien, CRANE Program Manager at DARPA. “His CRANE X-plane, with its modular wing section and modular AFC effector, has the potential to continue as a national test asset after the CRANE program ends.”
“Given all that we have learned about AFC and its application to tactical aircraft during the previous stages of CRANE, the next step is to prove these learnings in flight,” said Aurora’s Vice President of Government Programs. One Graham Drozeski adds. “The CRANE X-plane is specifically designed to investigate the effectiveness of AFC technology at mission-relevant scales and Mach numbers.”
Source: DARPA
