• Title/Summary/Keyword: Unstable Pitch

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In-Flight Simulation for the Evaluation of Flight Control Law (비행제어계 평가를 위한 항공기 공중모의 비행시험)

  • Go,Jun-Su;Lee,Ho-Geun;Lee,Jin-Yeong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.10
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    • pp.79-88
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    • 2003
  • The paper presented here covers the work associated with the flight control law design, ground based and in flight simulation and handling qualities assessment of the Fly-by-Wire type Aircraft (FBWA). The FBWA configurations are of the same generic form of the Korean advanced trainer. The normal acceleration (Nz) and pitch rate (q) feedback control system is employed for longitudinal axis and roll rate (p) and lateral acceleration (Ny) feedback flight control law is developed in lateral/ directional axis. The flight tests for the FBW A dynamics evaluation were executed for the target aircraft (FBWA) on the IFS (In-Flight-Simulator) aircraft . The test results showed that Level 1 handling qualities for the most unstable flight regime and Level 1/2 for the landing approach flight regime were achieved. And the designed FBWA flight control law has revealed acceptable CHR (Cooper-Harper handling qualities Ratings).

Computational Fluid Dynamics of the aerodynamic characteristics for Flying Wing configuration with Flaperon (플래퍼론이 전개된 플라잉윙 형상의 공력 특성에 대한 전산유동해석)

  • Ko, Arim;Chang, Kyoungsik;Park, Changhwan;Sheen, Dongjin
    • Journal of Aerospace System Engineering
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    • v.13 no.5
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    • pp.32-38
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    • 2019
  • The flying wing configuration with high sweep angles and rounded leading edge represent a complex flow of structures by the leading edge vortex. For control of the tailless flying wing configuration with unstable directional stability, flaperon is used. In this study, we conducted numerical simulations for a non-slender flying wing configuration with a rounded leading edge and analyzed the effect of the sideslip angle and flaperon. Through aerodynamic coefficient analysis, it was found that the effect of AoS on lift and drag coefficient was minimal and the side force and moment coefficient were markedly influenced by AoS. As the sideslip angle increased, the pitch break, which is related to the pitching moment coefficient, was delayed. Through stability analysis, the directional and lateral static stability of the flying wing configuration were increased by flaperon. Also, the structure and behavior of the leading edge vortex were analyzed by observing the contour of the pressure coefficient and the skin friction line.

In vivo 3D Kinematics of Axis of Rotation in Malunited Monteggia Fracture Dislocation

  • Kim, Eugene;Park, Se-Jin;Jeong, Haw-Jae;Ahn, Jin Whan;Shin, Hun-Kyu;Park, Jai Hyung;Lee, Mi Yeon;Tsuyoshi, Murase;Sumika, Ikemototo;Kazuomi, Sugamoto;Choi, Young-Min
    • Clinics in Shoulder and Elbow
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    • v.17 no.1
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    • pp.25-30
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    • 2014
  • Background: Normal elbow joint kinematics has been widely studied in cadaver, whilst in vivo study, especially of the forearm, is rare. Our study analyses, in vivo, the kinematics of normal forearm and of malunited forearm using a three-dimensional computerized simulation system. Methods: We examined 8 patients with malunited Monteggia fracture and 4 controls with normal elbow joint. The ulna and radius were reconstructed from CT data placing the forearm in three different positions; full pronation, neutral, and full supination using computer bone models. We analyzed the axis of rotation 3-dimentionally based on the axes during forearm rotation from full pronation to full supination. Results: Axis of rotation of normal forearm was pitch line, with a mean range of 2 mm, from full pronation to full supination, connecting the radial head center proximally and ulnar fovea distally. In normal forearm, the mean range was 1.32 mm at the proximal radioulnar joint and 1.51 mm at the distal radioulnar joint. However in Monteggia fracture patients, this range changed to 7.65 mm at proximal and 4.99 mm at distal radoulnar joint. Conclusions: During forearm rotation, the axis of rotation was constant in normal elbow joint but unstable in malunited Monteggia fracture patients as seen with radial head instability. Therefore, consideration should be given not only to correcting deformity but also to restoring AOR by 3D kinematics analysis before surgical treatment of such fractures.