News & Analysis
Tomorrow's aircraft flies without flaps
R Colin Johnson
4/3/2006 9:00 AM EDT
The second method, fluidic thrust vectoring (FTV), changes the direction of a main jet with a smaller, control jet. Like circulation control, FTV harnesses the Coanda effect, but in this case it does so to to deflect the main jet by using higher pressure directed along the jet's upper wall. As a consequence, the main jet vectors upward in proportion to the force from the control jet.
The control jets are just compressed air nozzles--zero-mass actuators--sized at half the height of the boundary air layer around the wings, or about 5 millimeters. A typical flapless aircraft might have hundreds of separate fixed-direction control jets, for quickly changing the flying surface to effect control.
The algorithms for controlling the jets are being modeled using a large eddy simulation (LES) at the Imperial College of Science, Technology and Medicine, which is also experimenting with deformations of small deflector surfaces as an alternative to cavity oscillators. Imperial College is seeking improved adaptive, nonlinear algorithms aimed at increasing the robustness of the artificial intelligence.
The brains of the artificial intelligence will be crafted by Leicester, which plans to integrate distributed control that would dynamically interact in real-time to affect coordinated maneuvers and engine control. The Leicester software would fuse the data streams of large arrays of redundant microsensors to move the microactuator arrays for control-jet management.
In the movie Stealth, a lightning strike "rewires" the craft's artificial intelligence. The Universities of Nottingham, Wales Swansea and York are working on eliminating that possibility in the Flaviir craft.
The goal is to design complex, repetitive patterns of small gaps, slots, cables and wires to be able to harness carbon fiber structures to cancel the effects of electromagnetic pulses by absorbing them without damaging the electronics. Nottingham is modeling the small-scale electrical devices to be used within the large-scale structures of the aircraft. Swansea will model the hybrid mesh, and York will model the materials.
Manufacturing techniques that reduce costs by reinforcing fabrics with laminates, stitching and tufting will be developed at Cranfield University. Warwick University will develop low-volume tooling techniques that enable the UAVs to be heavily modified for each application while keeping the costs as low as if a standard model were being mass produced.
Direct laser fabrication techniques, developed at the University of Liverpool, will integrate both physical reinforcing and electronic shielding within the carbon fiber exterior material. The University of Southampton will create a computer-aided design system that will allow what-if scenarios to determine the cost of integration trade-offs based on complexity, function and mission importance.
Cranfield University is managing the entire project. Its responsibilities include feeding back problem areas in integration issues to the original design teams so errors can be corrected. The Cranfield team will also evaluate the ideas that the other teams come up with during the design phase so that the design can be upgraded as experiments validate new techniques.
The Flaviir project is being linked to other aerospace research already under way in Europe, including the Puma and Msttar projects under the U.K.'s Defence and Aerospace Research Partnership (Darp). Those projects are pursuing aero-elastics and turbulence, respectively, with the intent of modeling and steadying aerodynamics and performance.

