Boeing 787 Dreamliner - Mark Wagner [52]
Boeing tested a “smooth ride” vertical and lateral gust suppression system using the M-CAB multipurpose generic motion flight cockpit simulator. A set of static air data sensors detected pressure differentials created by the onset of turbulence and fed flight control system commands to the ailerons, spoilers, and elevons that compensated for the motion. The goal was to avoid inertial, roller coaster responses and instead to ride through the turbulence by damping out the motion. The result, said Boeing, was a ride that felt more like riding in a fast car over cobblestones than the large amplitude, lurching upheavals normally encountered. Mark Wagner
The GE Aviation high-lift actuation system powered, actuated, and monitored the flap and slat system, as well as repositioned the trailing edge surfaces during operation of the Variable Camber system during flight, to reduce drag. Moog provided the primary flight control actuation system on all of the flight control surfaces, as well the spoilers and horizontal stabilizers. Each wing packed nine electrohydraulic servo-actuators with integral control electronics, as well as two simplex electromechanical actuators and two motor-drive controllers. An electrical backup for actuation system for both the leading edge slats and the trailing-edge flaps was developed by Sweden’s Saab Avitronics. Mark Wagner
Boeing’s determination to embrace a more electric architecture became clear in 2004, when it awarded the U.K.-based companies Ultra Electronics and GKN Aerospace the role of developing an electrically powered wing ice protection system. This traditionally had been performed using hot bleed air from the engines that was ducted along the wing’s leading edge via a “piccolo” tube.
In these conventional systems, the spent bleed air was exhausted through holes in the lower surface of the wing or slat. However, the 787 became the first commercial aircraft application of an electrothermal system originally used on the blades of military rotorcraft such as the AgustaWestland AW101 and the Bell Boeing V-22 Osprey. The system was made up of several electrically heated elements contained within a sprayed metal matrix bonded to the inside of the leading edges by a polymer composite material. The heating blankets were designed to be energized simultaneously for anti-icing protection or sequentially for deicing to heat the wing’s leading edge.
Boeing predicted that this method was significantly more efficient than the traditional system because no excess energy was exhausted. As a result, the required ice protection power usage was approximately half that of pneumatic systems. Moreover, because there were no bleed air exhaust holes, airplane drag and noise reduction were also expected to improve. “It turned out to be a good system for us, mostly because it protects the efficiency of the aerofoil shape with high integrity,” said Sinnett. “There are multiple zones for each leading edge section, and in case of a failure, we’d only lose coverage of around one sixth of one slat.” An added benefit is “we can also do this with around half the power that we’d need to deice pneumatically.”
Early trials of the concept in Boeing’s own research anti-icing tunnel in Seattle led to some tweaks in the configuration but otherwise confirmed the baseline design. “We altered the design a bit on the heating blanket, which has now been moved further aft on the underside of the leading edge of the slat. We ended up