• Title/Summary/Keyword: aircraft wing

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Performance Analysis of Autorotation(2) : Performance of High Speed Autorotaion (자동회전의 성능해석(2) : 고속 자동회전의 성능)

  • Kim, Hak-Yoon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.40 no.1
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    • pp.12-22
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    • 2012
  • Performance variation of autorotating rotor was investigated. The shaft angle of the rotor is reduced while the flight velocity is increased. The BO-105 helicopter rotor blade was replaced by untwisted NACA 0012 airfoil and the rotor was simulated by using Transient Simulation Method(TSM) to judge the autorotation region for the variables. To simulate the compressibility effect at high speed flight, two-dimensional aerodynamic data was analyzed by compressible Navier-Stokes solver and Pitt/Peters inflow theory was adopted to simulate the induced velocity field. Thrust and lift coefficients, lift to drag ratio variations were investigated, also the lift and power were compared to those of BO-105 helicopter. Sharing lift and power between the autorotating rotor and wing was considered when the compound aircraft concept is introduced.

SELECTION OF THE OPTIMAL POSITION OF THE FLAP FOR THE IMPROVEMENT OF AERODYNAMIC PERFORMANCE (공기역학적 성능 향상을 위한 플랩의 최적 위치 선정)

  • Kang, H.M.;Park, Y.M.;Kim, C.W.;Lee, C.H.
    • Journal of computational fluids engineering
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    • v.18 no.4
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    • pp.41-46
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    • 2013
  • The selection of the optimal position of the flap was performed in order to improve the aerodynamic performance during the take-off and landing processes of aircraft. For this, the existing airfoils of the main wing and flap are selected as the baseline model and the lift coefficients (cl) according to angle of attacks (AOA) were calculated with the change of the position of flap airfoil. The objective function was defined as the consideration of the maximum cl, lift to drag ratio and cl at certain AOA. Then, at 121 experimental points within $20mm{\times}20mm$ domain, two dimensional flow simulations with Spalart-Allmaras turbulence model were performed concerning the AOA from 0 to 15 degree. If the optimal position was located at the domain boundary, the domain moved to the optimal position. These processes were iterated until the position was included in the inside of the domain. From these processes, the flow separation at low AOA was removed and cl increased linearly comparing with that of the baseline model.

Loads Analysis of Smart UAV Using ARGON (ARGON을 이용한 스마트 무인기 비행하중해석)

  • Shin, Jeong-Woo;Kim, Sung-Chan;Hwang, In-Hee
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.7
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    • pp.76-84
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    • 2005
  • For flight loads analysis of Smart UAV, applicable regulations and loads conditions should be prepared in advance, and modeling for aerodynamics, weight, and structure should be performed. Panel method is usually adopted for aircraft loads analysis to obtain aerodynamic loads. In this study, ARGON which is a multidisciplinary fixed wing aircraft design software co-developed by KARI and TsAGI was used for loads analysis. ARGON can be utilized for flutter and stress analysis as well as for flight and ground loads analysis. In this paper, flight loads analysis of Smart UAV which is a FAR 23 category airplane was performed with ARGON and the results were presented.

Development of Icing Simulation Device for Gas Turbine Icing Test (가스터빈 결빙시험용 결빙모사장치 개발)

  • Lee, Kyung-Jae;Yang, Soo-Seok;Lee, Dae-Sung
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.04a
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    • pp.358-361
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    • 2007
  • Most aircraft cruise in the stratosphere at which temperature is below $-50^{\circ}C$ md, as a result, the surface of aircraft can be iced up. Ice on the wing can change aerodynamic characteristic and results in the deterioration of its performance. Ice on the engine inlet increases the possibility of compressor blade damage and affects the performance and safety of the engine. This paper focused on the development of icing simulation device for analyzing effect of icing on engine performance. Icing simulation tests were conducted with a liquid air system and a icing simulation device and results show that icing could be simulated with this system.

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Improving aeroelastic characteristics of helicopter rotor blades in forward flight

  • Badran, Hossam T.;Tawfik, Mohammad;Negm, Hani M.
    • Advances in aircraft and spacecraft science
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    • v.6 no.1
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    • pp.31-49
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    • 2019
  • Flutter is a dangerous phenomenon encountered in flexible structures subjected to aerodynamic forces. This includes aircraft, helicopter blades, engine rotors, buildings and bridges. Flutter occurs as a result of interactions between aerodynamic, stiffness and inertia forces on a structure. The conventional method for designing a rotor blade to be free from flutter instability throughout the helicopter's flight regime is to design the blade so that the aerodynamic center (AC), elastic axis (EA) and center of gravity (CG) are coincident and located at the quarter-chord. While this assures freedom from flutter, it adds constraints on rotor blade design which are not usually followed in fixed wing design. Periodic Structures have been in the focus of research for their useful characteristics and ability to attenuate vibration in frequency bands called "stop-bands". A periodic structure consists of cells which differ in material or geometry. As vibration waves travel along the structure and face the cell boundaries, some waves pass and some are reflected back, which may cause destructive interference with the succeeding waves. In this work, we analyze the flutter characteristics of a helicopter blades with a periodic change in their sandwich material using a finite element structural model. Results shows great improvements in the flutter forward speed of the rotating blade obtained by using periodic design and increasing the number of periodic cells.

Analysis of Flight Performance and Efficiency according tothe Number of Consecutive Flight of Navy Pilots (해군 고정익조종사의 비행 훈련 주기에 따른 비행 효과 분석)

  • JungBong Lee
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.31 no.2
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    • pp.66-71
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    • 2023
  • In the case of the Navy, if some of the co-pilots are included in the long-term promotion process due to the limited number of co-pilots, operational flight and administrative tasks will be added to the co-pilots not included in the rest of the Pilot in commander process. Therefore, to solve this problem, the co-pilot who has passed the PQS step-by-step process minimizes the personnel gap in the flight operation unit through a system that evaluates whether it is possible to perform its duties as a co-pilot through actual flight after entering the school. The advantage of the PQS course is that you can control flight plans on your own and minimize gaps in flight and ground work while carrying out the curriculum, but you can't focus on education or improve your skills due to irregular training flight cycles. Therefore, in this study, after collecting opinions on effective flight cycles through a survey of pilots of P-3C, the Navy's fixed-wing aircraft representative, we will analyze the association of aircraft volume performance by flight cycle to derive the optimal flight cycle of the P-3C pilot course.

A Study on the Techniques of Path Planning and Measure of Effectiveness for the SEAD Mission of an UAV (무인기의 SEAD 임무 수행을 위한 임무 경로 생성 및 효과도 산출 기법 연구)

  • Woo, Ji Won;Park, Sang Yun;Nam, Gyeong Rae;Go, Jeong Hwan;Kim, Jae Kyung
    • Journal of Advanced Navigation Technology
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    • v.26 no.5
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    • pp.304-311
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    • 2022
  • Although the SEAD(suppression to enemy air defenses) mission is a strategically important task in modern warfare, the high risk of direct exposure to enemy air defense assets forces to use of unmanned aerial vehicles. this paper proposes a path planning algorithm for SEAD mission for an unmanned aerial vehicle and a method for calculating the mission effectiveness on the planned path. Based on the RRT-based path planning algorithm, a low-altitude ingress/egress flight path that can consider the enemy's short-range air defense threat was generated. The Dubins path-based Intercept path planning technique was used to generate a path that is the shortest path while avoiding the enemy's short-range anti-aircraft threat as much as possible. The ingress/intercept/egress paths were connected in order. In addition, mission effectiveness consisting of fuel consumption, the survival probability, the time required to perform the mission, and the target destruction probability was calculated based on the generated path. The proposed techniques were verified through a scenario.

Development and Assessment of Crashworthy Composite Subfloor for Rotorcrafts (회전익 항공기용 복합재 내추락 하부동체 구조 개발 및 검증)

  • Park, Ill Kyung;Lim, Joo Sup;Kim, Sung Joon;Kim, Tae-Uk
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.46 no.1
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    • pp.18-31
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    • 2018
  • Rotorcrafts have more severe crashworthiness conditions than fixed wing aircraft owing to VTOL and hovering. Recently, with the increasing demand for highly efficient transportation system, application of composite materials to aircraft structures is increasing. However, due to the characteristics of composite materials that are susceptible to impact and crash, demand to prove the crashworthiness of composite structures is also increasing. The purpose of present study is to derive the structural concept of composite subfloor for rotorcrafts and verify it. In order to design a crashworthy composite subfloor, the conceptual design of the testbed helicopter for the demonstration and the derivation of energy absorbing requirement were carried out, and the composite energy absorber was designed and verified. Finally, the testbed for the demonstration of a crashworthy composite structure was fabricated, and performed free drop test. It was confirmed that the test results meet the criteria for ensuring occupant survivability.

S/W Development of Flying Qualities Evaluation in Virtual Flight Test using MATLAB GUI (GUI 기반 가상모의시험 비행성 평가 S/W 개발)

  • Cho, Seung-Gyu;Rhee, Ihn-Seok;Kim, Byoung-Soo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.41 no.1
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    • pp.61-69
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    • 2013
  • In an evaluation process of aircraft flying qualities, a clear and concise application interface is important since an evaluation process requires numerous repeated evaluation. This flight evaluation program have implemented efficient flight evaluation user interface along with changed trim condition interface and composed of comprehensive evaluation interface have mounted all automated FQ evaluation modules that was selected to be compose of 14 items in respect of an unmanned fixed-wing aircraft. Accordingly when it is necessary to design the flight control system as well as to develop a FQ considered aircraft, this S/W can be utilized as a tool that is a useful test evaluation S/W with scalability and enable to reduce the time and the cost of verification and evaluation process.

Sand particle-Induced deterioration of thermal barrier coatings on gas turbine blades

  • Murugan, Muthuvel;Ghoshal, Anindya;Walock, Michael J.;Barnett, Blake B.;Pepi, Marc S.;Kerner, Kevin A.
    • Advances in aircraft and spacecraft science
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    • v.4 no.1
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    • pp.37-52
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    • 2017
  • Gas turbines operating in dusty or sandy environment polluted with micron-sized solid particles are highly prone to blade surface erosion damage in compressor stages and molten sand attack in the hot-sections of turbine stages. Commercial/Military fixed-wing aircraft engines and helicopter engines often have to operate over sandy terrains in the middle eastern countries or in volcanic zones; on the other hand gas turbines in marine applications are subjected to salt spray, while the coal-burning industrial power generation turbines are subjected to fly-ash. The presence of solid particles in the working fluid medium has an adverse effect on the durability of these engines as well as performance. Typical turbine blade damages include blade coating wear, sand glazing, Calcia-Magnesia-Alumina-Silicate (CMAS) attack, oxidation, plugged cooling holes, all of which can cause rapid performance deterioration including loss of aircraft. The focus of this research work is to simulate particle-surface kinetic interaction on typical turbomachinery material targets using non-linear dynamic impact analysis. The objective of this research is to understand the interfacial kinetic behaviors that can provide insights into the physics of particle interactions and to enable leap ahead technologies in material choices and to develop sand-phobic thermal barrier coatings for turbine blades. This paper outlines the research efforts at the U.S Army Research Laboratory to come up with novel turbine blade multifunctional protective coatings that are sand-phobic, sand impact wear resistant, as well as have very low thermal conductivity for improved performance of future gas turbine engines. The research scope includes development of protective coatings for both nickel-based super alloys and ceramic matrix composites.