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Still a fractional-scale testbed at Boeing's Phantom Works/NASA's Dryden, but making real progress towards developing blended-wing commercial/military aircraft.
New Tests Pending For X-48 Flying Wing
MOFFETT FIELD, Calif. — NASA’s Dryden Flight Research Center expects to enter a second phase of flight tests of Boeing’s tailless flying-wing X-48B as early as next week.
Those tests are a prelude to introduction of a revised version of the hybrid-wing aircraft in about a year that will be more fuel efficient, have lower emissions, and more closely resemble NASA’s ideal for hybrid wing-body aircraft.
But before the switch to the advanced X-48C can be made, NASA will conduct 10-12 additional X-48B flights to isolate the handling characteristics of each of its 20 control surfaces, NASA Project Manager Tim Risch says. These tests will build on the 80 Phase 1 flights that verified the aircraft’s basic configuration, which concluded last spring.
The X-48 team has developed algorithms that can excite all 20 of its control services simultaneously, but in a way that they move out of phase with each other, Risch explains during a NASA Green Aviation Summit at the Ames Research Center here. By using a correlation of the basic control algorithm, each movable surface can be characterized individually.
Risch expects it will take less than two months to conduct the 10-12 control surface verification flights. All will be flown within Dryden’s Remotely Operated Vehicle area.
By late November, the X-48B should be ready for engine modifications. As presently configured, it has a 21.5-ft. wingspan and is powered by three 50-lb. thrust turbojet engines from JetCat, a model-aircraft turbine-engine specialist. They are rear-mounted on top of the aircraft. The goal is to swap these out for two 80-lb. thrust geared turbofans to turn the flying wing into the X-48C. The new engines are still in design, however. They have a nominal fan diameter of 12 in.
The engine development flight tests will come in two steps. Initially, one of the 80-lb. turbofans will be flown nestled between two turbojets to establish its basic flight characteristics while maintaining the safety margin of flying with the other two proven turbojets.
A second modification to the new aircraft will be the transfer of its tails from a pair of winglets inboard to become tails mounted just outside the engine nacelles to shield noise from the turbofans.
Risch expects it will take only 1-2 flights to verify the single turbofan’s operating characteristics before the full transition to the X-48C model can be completed. Transition of the X-48B into the C-model can be completed by turning it into a two-engine, turbofan-powered aircraft. The airframe was built by Cranfield Aerospace for Boeing’s Phantom Works research arm.
Previously, Boeing was charged with establishing the X-48’s air worthiness, flight safety envelope and mission success. The mission success role will be split with Dryden in the new flights. The NASA center will be responsible for the yaw control studies, single surface tests and intelligent control for performance evaluation.
Early in the program, the Phantom Works/Dryden partnership expected to adapt a wind tunnel test article for the X-48C flight model. But the current thinking is that the B model will be easier to modify, Risch says.
MOFFETT FIELD, Calif. — NASA’s Dryden Flight Research Center expects to enter a second phase of flight tests of Boeing’s tailless flying-wing X-48B as early as next week.
Those tests are a prelude to introduction of a revised version of the hybrid-wing aircraft in about a year that will be more fuel efficient, have lower emissions, and more closely resemble NASA’s ideal for hybrid wing-body aircraft.
But before the switch to the advanced X-48C can be made, NASA will conduct 10-12 additional X-48B flights to isolate the handling characteristics of each of its 20 control surfaces, NASA Project Manager Tim Risch says. These tests will build on the 80 Phase 1 flights that verified the aircraft’s basic configuration, which concluded last spring.
The X-48 team has developed algorithms that can excite all 20 of its control services simultaneously, but in a way that they move out of phase with each other, Risch explains during a NASA Green Aviation Summit at the Ames Research Center here. By using a correlation of the basic control algorithm, each movable surface can be characterized individually.
Risch expects it will take less than two months to conduct the 10-12 control surface verification flights. All will be flown within Dryden’s Remotely Operated Vehicle area.
By late November, the X-48B should be ready for engine modifications. As presently configured, it has a 21.5-ft. wingspan and is powered by three 50-lb. thrust turbojet engines from JetCat, a model-aircraft turbine-engine specialist. They are rear-mounted on top of the aircraft. The goal is to swap these out for two 80-lb. thrust geared turbofans to turn the flying wing into the X-48C. The new engines are still in design, however. They have a nominal fan diameter of 12 in.
The engine development flight tests will come in two steps. Initially, one of the 80-lb. turbofans will be flown nestled between two turbojets to establish its basic flight characteristics while maintaining the safety margin of flying with the other two proven turbojets.
A second modification to the new aircraft will be the transfer of its tails from a pair of winglets inboard to become tails mounted just outside the engine nacelles to shield noise from the turbofans.
Risch expects it will take only 1-2 flights to verify the single turbofan’s operating characteristics before the full transition to the X-48C model can be completed. Transition of the X-48B into the C-model can be completed by turning it into a two-engine, turbofan-powered aircraft. The airframe was built by Cranfield Aerospace for Boeing’s Phantom Works research arm.
Previously, Boeing was charged with establishing the X-48’s air worthiness, flight safety envelope and mission success. The mission success role will be split with Dryden in the new flights. The NASA center will be responsible for the yaw control studies, single surface tests and intelligent control for performance evaluation.
Early in the program, the Phantom Works/Dryden partnership expected to adapt a wind tunnel test article for the X-48C flight model. But the current thinking is that the B model will be easier to modify, Risch says.