• Title/Summary/Keyword: Civil Helicopter

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Predicting Lift of Rotor Blade for Agricultural Unmanned Helicopter using CFD Simulation (CFD 시뮬레이션을 이용한 농용 회전익기의 로터블레이드 양력성능 예측)

  • Koo, Young Mo;Won, Yong Sik;Hong, Jong Geun;Ali, H.B.;Sohn, Chang Hyun
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 2017.04a
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    • pp.59-59
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    • 2017
  • 무인 헬리콥터의 양력을 개선하기 위한 익형 설계 단계로서 두꺼운 익형(V1505A)과 얇고 처진 익형(V2008B)의 기본 두 익형의 특성을 예측하는데 있어 회전하는 블레이드의 현실적 조건을 반영한 3D 모델을 마련하고 성능을 예측하였다. Fluent를 이용한 400 mm 선형모델의 시뮬레이션에서는 V1505A 익형은 높은 받음각에서 안정적인 특성을 보인 반면 V2008B는 비교적 높은 동력효율 특성을 보였으나, 높은 받음각에서는 실속 이후 양력이 급락하는 특성을 나타낸다. 형성된 노드 수는 약 870,000개로 하였다. 시위길이 135 mm인 익형 V2008B의 형상은 ANSYS (Fluent v16.2)를 이용해 반경(길이) 1,502 (1,380) mm 의 로터 블레이드를 구성하였다. 충분하지 않은 유동장이 익형 표면에서의 유동의 영향에 영향을 주지 않도록 직경 20 m의 원방경계(far field)를 형성하였다. 사용된 매쉬의 형태는 정사면체 형태로 로터 표면으로부터의 첫 번째 두께 높이는 0.001 m이고 10개의 층으로 형성하였다. 정지 비행하는 헬리콥터의 상태를 가정하여 회전좌표계를 이용하여 정상상태의 유동을 해석하고 사용된 난류모델은 넓은 영역에서의 유동을 고려하여 Realizable $k-{\varepsilon}$ 모델을 사용하였다. 내측그립 받음각 $6{\sim}22^{\circ}$에 대하여 현실적인 회전속도를 연동하여 600~1000 rpm을 적용하였다. 반복수(iteration)는 2000으로 하여 잔차값(residual)이 충분히 수렴하도록 하였다. 전체적으로 실제 헬리콥터가 발휘하는 양력보다는 낮은 수치로 예측되었으며 모델 및 해석 조건에 대한 검토가 필요해 보인다. 양력 값은 받음각 $10^{\circ}$에서 자중(약 68 kgf)을 극복하였고 받음각 $12^{\circ}$에 유상하중 20 kgf을 발휘하며 888 N의 양력을 보였다, 이어 받음각 $22^{\circ}$에서 실속 현상이 발생하였다. 받음각이 증가함에 따라 항력 역시 증가하였으며 받음각 $12^{\circ}$에서 121 N이었고 실속에 이르며 항력은 갑자기 증가할 것으로 예측된다. 본 연구는 변이 익형 개발의 선행 단계로 기본 익형에 대한 공력특성을 CFD 시뮬레이션을 통하여 예측하였다. 예측 값은 현실적 실험방법을 통하여 검증이 되어야 하며 이후 변이익형에 대한 예측과 설계가 가능하다.

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Establishing Engine Accelerated Mission Test Cycles complying with the CS-E of European Aviation Safety Agency (유럽항공안전청 형식증명 감항기준에 부합하는 엔진가속시험 사이클 수립)

  • Park, Sooyoul;Moon, Gyeongchan;Koo, Hyuncheol
    • Journal of Aerospace System Engineering
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    • v.14 no.1
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    • pp.62-67
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    • 2020
  • The European Aviation Safety Agency (EASA) legislates the CS-E (Certification Specification-Engine) for type certification of aircraft engines. According to the CS-E, engine manufacturers (type certificate holders) the need to show compliance of continued airworthiness of an engine during the overhaul, and the Accelerated Mission Test (AMT) is usually accepted as means of compliance. As a part of the Korean Civil Helicopter program, the engine has been developed with foreign manufacturers to achieve the EASA engine type certificate. In this study, the AMT procedure is planned for the engine to be certified by the EASA, and AMT cycles are also established to meet airworthiness requirements of the CS-E in consideration of the engine design and operation characteristics.

A Case Study on Safety Analysis Procedure of Aircraft System using the Relex (Relex를 이용한 항공기 시스템 안전성 평가 절차 사례분석)

  • Lee, Dong-Woo;Kim, Ip-Su;Na, Jong-Whoa
    • Journal of Advanced Navigation Technology
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    • v.22 no.3
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    • pp.179-188
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    • 2018
  • In developing avionics systems, safety analysis and evaluation specified in SAE ARP4761 (Methods and Guidelines for Civil Aviation System and Equipment Safety Assessment Process) are carried out to prevent air accidents. Safety analysis requires knowledge of the abnormal state of the system, not its normal state, and its interrelationships with other standards. Therefore, a tool that automatically outputs data which proves compliance with safety certification standards is required. In this study,In this study, Schematized the safety analysis procedure of the specification and studied the method of applying the safety analysis CAD tools to individual procedure. As an example study, ARP4761 analysis was performed on the wheel brake system (WBS) of the ARP4761 appendix.

A Design of Handling Quality Assessment Environment Based on FLIGHTLAB Model Using Legacy Simulator (레거시 시뮬레이터를 활용한 FLIGHTLAB 모델 기반의 조종성 평가 환경 설계 연구)

  • Yang, Chang Deok;Lee, Seung Deok;Cho, Hwan Heui;Jung, Dong Woo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.44 no.6
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    • pp.530-536
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    • 2016
  • The handling quality simulator including high fidelity flight mechanics model is indispensable component to design and verify the flight control system. Korea Aerospace Industries, LTD. (KAI) has been performing LCH (Light Civil Helicopter) core technology development program regarding automatic flight control system (AFCS) software development. And KAI has been developing flight mechanics model using FLIGHTLAB to design and evaluate the AFCS flight control law. This paper presents the handling quality assessment environment development results through the combining FLIGHTLAB with a legacy simulator. And this paper details the FLIGHTLAB model, application development process and FLIGHTLAB interface design. The developed handling quality assessment environment has been demonstrated with the ADS-33E hover and pirouette MTE (Mission Task Element) maneuver simulation.

Aerodynamic Characteristics of Basic Airfoils for Agricultural Helicopter using Wind-tunnel Test and CFD Simulation (풍동실험과 CFD 시뮬레이션을 이용한 농용 헬리콥터 기본 익형의 공력특성 고찰)

  • Won, Yong Sik;Koo, Young Mo;Haider, B.A.;Sohn, Chang Hyun
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 2017.04a
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    • pp.54-54
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    • 2017
  • 본 연구는 무인 헬리콥터의 양력을 개선하기 위한 기초 단계로서 V1505A 및 V2008B 기본 두 익형의 400 mm 블레이드 섹션에 해당하는 모델에 대한 풍동실험을 실시하여 양력, 항력 및 동력특성을 분석하고 CFD 시뮬레이션의 결과와 비교하고 검증하였다. 시뮬레이션은 풍동 실험과 유사하게 설정하기 위하여 400 mm 블레이드 섹션의 양 끝을 벽으로 제한하여 3차원 와류현상을 억제하여 모델을 구성하였고, 시뮬레이션의 결과와 비교하여 모델을 검증하였다. 사용된 모델은 로터로부터 $Re=0.32{\times}10^6$ 영역까지는 aminar 모델을 사용하였으며, 그 이후 영역역(>$Re=0.32{\times}10^6$)은 양력 및 저항의 급격한 변화를 올바로 포착할 수 있다는 S-A 모델을 적용하여 확장하였다. 시뮬레이션의 격자는 유동 현상에 있어 박리로 야기된 와류 현상을 관찰하기 위하여 익형 주변에 접하는 부분에 격자를 집중시켰다. 시뮬레이션 방법은 유속은 36~141 m/s 까지 5 수준으로 하였으며, 받음각은 $0{\sim}16^{\circ}$로 7 수준으로 변화 시키면서 공력계수 및 동력을 분석하였다. 양력분석에 있어 익형 V1505A에 비해 익형 V2008B의 특성이 우수하였으나, 익형 V1505A는 실속 이후 양력이 급격히 떨어지지 않고 유지되는 특성을 보였다. 익형 V2008B는 낮은 받음각에서 높은 공력과 낮은 항력을 나타냈다. 동력 분석 결과로 익형 V1505A의 유도동력은 총 동력의 56~72%를 차지하고, 형상동력은 총 동력의 27~43%를 차지하였다. 익형 V2008B는 유도동력은 총 동력의 66~81%를 차지하고, 형상동력은 총 동력의 18~33%를 차지하였다. 익형 V2008B이 익형 V1505A보다 유도동력은 크며, 형상동력은 적게 나와 상대적으로 효율적이라 할 수 있다. 헬리콥터 동력원의 규모는 법률적인 총중량에 의하여 제한되므로 일반적인 농용 소형 무인 헬리콥터 엔진의 사양인 24.5 kW (32PS)를 적용한다면, 익형 V1505A은 받음각 $8{\sim}10^{\circ}$에서 그리고 익형 V2008B은 $7{\sim}9^{\circ}$정도에서 받음각이 제한되며 이때 총 양력은 1200~1300 N 정도로 예상된다.

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Legal Issue in Case of Death or Injury of an International Crew While on Board (국제항공운송 승무원이 항공기내에서 사상(死傷)을 당한 경우 법률관계 - 국내외 판례의 분석을 중심으로 -)

  • Kim, Sun-Ah
    • The Korean Journal of Air & Space Law and Policy
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    • v.35 no.2
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    • pp.137-168
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    • 2020
  • Air passengers may be compensated for damages based on the above agreement when the passenger suffers an accident to the extent that they are recognized as an accident under Article 17 of the Montreal Convention in 1999. If a flight or cabin crew and passengers both undergo an accident, passengers are subjected to compensation under the Montreal Convention however flight cabin crews will be compensated by the Labor Law, which is the governing law in the labor contract with the airline. The flight or cabin crew boarding the aircraft work is on a work contract, not a passenger transport contract. Therefore, if the flight or cabin crew on the aircraft is injured due to an accident, and the air carrier is liable for default due to a labor contract, the Labor Law, workers or survivors claim damages due to illegal acts against the employer. In which case, civil law will apply. In this regard, if a Chinese cabin crew working for a Chinese airline dies due to an accident in the Republic of Korea, whether the family of the deceased claims damages against the Chinese airline or not has international court jurisdiction in the Republic of Korea, which is the place of tort. We examined whether it is the law of the Republic of Korea or whether it's the Chinese law, the law applicable to the work contract, is applied. Also, Seoul District Court 1995.5.18. The sentence 94A 14144 was found that if the injured crew during the flight work was not satisfied with the insurance compensation under the Labor Standards Act and the Industrial Accident Compensation Insurance Act, he could claime to damage under the civil law against an air carrier or third parties responsible for the accident. This law case shows that you can claim a civil damage as a cause. In case of death due to an existing illness while on the way to work, the Korea Workers'Compensation and Welfare Service did not recognize the death of the deceased as an occupational accident, and the trial was canceled by the parents of the deceased for the survivor's benefit and funeral expenses. (Seoul Administrative Court 2017.8. 31. Although the sentence was judged as an occupational disaster in 2016, the 2016 8816 Decision), it was defeated in the appeals court (Seoul High Court 2018.7.19.Sentence 2017 No. 74186) and I criticized the judgment of the appeal by analyzing the deceased's disease and related the cause of it to workload. Sometimes, a flight or cabin crew is on board not for the flight duty such as transferring to another flight or returning to the home base or lay-over place after their scheduled flight, this is called "Deadheading". If the crew who is not considered the same as a passenger, but is not on duty, is injured in an accident, does the crew claim compensation for damages under the labor contract or whether the Montreal Convention is applied to the passenger. In conjunction with the discussion, there was a similar case, In re Mexico City Aircrash of October 31, 1979, 708 F.2d 400 (9th Cir. 1983), Demanes v. United Airlines, 348 F.Supp. 13 (C.D.Cal. 1972), Sulewski v. Federal Express Corp., 749 F.Supp. 506 (S.D.N.Y. 1990) and reviewed by the European Court of Justice (CJEU) at Wucher Helicopter GmbH and Euro-Aviation Versicherungs AG v. After examining several acts in several countries it's undeniably crucial to clearly understand the definition of "passenger" as stated in the Fridolin Santer case.

A study of the status of UAS Certification System and Airworthiness Standards (민간 무인항공기시스템 인증체계 현황 및 관련규정 연구 동향 분석)

  • Ahn, Hyojung;Park, Jonghyuk;Yoo, Seungwoo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.42 no.10
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    • pp.893-901
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    • 2014
  • UAS and related technology have been mainly developed for military use but, in recent years, various types of civil UAS have been using in a variety of applications. For example, there are multicopters to shoot aerial photography, pesticide spraying unmanned helicopter, and in addition there are radio control (R/C) aircraft to be used for hobbyists. UAV has spread rapidly enough that permitted experts as well as the public can use it but the related safety regulations are not properly equipped. We investigated the status of domestic and international UAS certification system and airworthiness standards. And the trends in research for the development and modification of the certification system were studied in this paper. As a result, most countries have studied to develop the related regulations and especially ICAO has tried to develop RPAS manual, standards and recommended plans and modify the related ICAO annex through the research group, ICAO UASSG. Based on the manual and SARPs, authorities, related organizations and companies have prepared to develop and modify regulations in accordance with the actual situation of each country.

Airloads and Structural Loads Analysis of LCH Rotor Using a Loose CFD/CSD Coupling (유체-구조 연계해석을 통한 소형민수헬기(LCH) 공력 및 구조하중 해석)

  • Lee, Da-Woon;Kim, Kiro;Yee, Kwan-Jung;Jung, Sung-Nam
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.47 no.7
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    • pp.489-498
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    • 2019
  • The airloads and structural loads of Light Civil Helicopter (LCH) rotor are investigated using a loose CFD/CSD coupling. The structural dynamics model for LCH 5-bladed rotor cwith elastomeric bearing and inter-bladed damper is constructed using CAMRAD-II. Either isolated rotor or rotor-fuselage model is used to identify the effect of the fuselage on the aeromechanics behavior at a cruise speed of 0.28. The fuselage effect is shown to be marginal on the aeromechanics predictions of LCH rotor, though the effect can be non-negligible for the tail structure due to the prevailing root vortices strengthened by the fuselage upwash. A lifting-line based comprehensive analysis is also conducted to verify the CFD/CSD coupled analysis. The comparison study shows that the comprehensive analysis predictions are generally in good agreements with CFD/CSD coupled results. However, the predicted comprehensive analysis results underestimate peak-to-peak values of blade section airloads and elastic motions due to the limitation of unsteady aerodynamic predictions. Particularly, significant discrepancies appear in the structural loads with apparent phase differences.