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Flying Wings (or Tailless Airplanes)
Published in James DeLaurier, Aircraft Design Concepts, 2022
These two examples of aircraft differ from the swept straight-tapered linear-twisted configurations previously discussed. Calculations for the parameters: xac, c¯, CL and CMac are more involved for such compound planforms. A reference discussing these, as well as other aspects of flying-wing designs, is “Tailless Aircraft in Theory and Practice” by Karl Nickel and Michael Wohlfahrt, published by Elsevier, 1994.
Fault Accommodation with Consideration of Control Authority and Gyro Availability
Published in Xiang Yu, Lei Guo, Youmin Zhang, Jin Jiang, Autonomous Safety Control of Flight Vehicles, 2021
Xiang Yu, Lei Guo, Youmin Zhang, Jin Jiang
Angular rate sensors (also named gyroscopes or gyros) are the primary measurement units in FCSs. The failure rate of gyros is ranked the highest among the key components in an inertial measurement unit (IMU) [58]. With respect to gyros, the research outcomes underscore the analytical redundancy's potential of offering reliable angular rates [14, 173, 174, 175, 176]. The reconstructed angular rates are used for an advanced tailless aircraft [173]. Considering additive faults [174] and incipient faults [14] in aircraft gyros, the pitch rate signal is reconstructed using a sliding mode observer (SMO). The tracking problem for vertical take-off and landing (VTOL) aircraft with sensorless angular velocities is studied in Ref. [175], where an observer-based approach is exploited to estimate the angular rates. More recently, the fully connected cascade neural network (NN) architecture is adopted to detect and recover the aircraft gyro failures [176].
Actuator energy and drag minimization of a blended-wing-body with variable-camber continuous trailing-edge flaps
Published in Engineering Optimization, 2020
The use of multiple control surfaces or VCCTEFs has been proved to improve aircraft performance significantly compared with using conventional single-element flaps (Zink, Mavris, and Raveh 2001; Nguyen and Urnes 2012; Xu and Kroo 2014; Stanford 2016; Zhao and Kapania 2017). However, the benefit of using multiple control surfaces could be counteracted by the increased weight of the actuators and/or the increased actuator energy required. The higher the number control surfaces the wing has, the higher the number of actuators needed to maintain the optimal control surface shape during different flight conditions. As a result, higher values of both the required control energy and actuator weight are needed. This is because the loads used in sizing the actuators depend on the applied hinge moment (Garmendia, Chakraborty, and Mavris 2015b). Most available previous research studies did not take into account the required energy consumption for the actuators when using multiple control surfaces for improving aircraft performance. This could be explained by the fact that the control surfaces are locked in a certain shape for traditional aircraft design and an enormous knowledge base exists for designing control surfaces for these aircraft. However, for tailless aircraft, the control surfaces are allowed to rotate freely to improve the dynamic aeroelastic performance, such as flutter suppression and gust load alleviation, in addition to improving aerodynamic efficiency during cruising.