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Prediction of the Blade Flapping Angle for Korean Utility Helicopter by Applying Indirect Method

간접기법을 이용한 한국형 기동헬기 블레이드 플래핑 각도 예측

  • Kim, Young-Jin (Sacheon Regional Center, Defense Agency for Technology and Quality) ;
  • Lee, Sang-Gi (Research & Development Division, Korea Aerospace Industries) ;
  • Lee, Seung-Jae (Research & Development Division, Korea Aerospace Industries) ;
  • Chang, In-ki (Sacheon Regional Center, Defense Agency for Technology and Quality) ;
  • Shim, Dai-Sung (Sacheon Regional Center, Defense Agency for Technology and Quality)
  • Received : 2015.07.29
  • Accepted : 2015.09.25
  • Published : 2015.10.01

Abstract

This paper shows an approximate equation which calculates a flapping angle of blade for verification of KUH safety area. The flapping behavior of blade must be reviewed in an aspect of safety because of a collision possibility with airframe. However, it is difficult to measure an exact flapping angle during flight. A prediction equation of a coning angle is derived from aeromechanics and that of a dynamic flapping angle is derived from analysis results in development phase, respectively. Following, the equations are verified by comparison the flapping angle through an aircraft simulation test to a calculation. Finally, the safety area, which was established in development phase, is verified by calculating a flapping angle during the flight which is required by the terms of safety based on AC29 and FAR29.

본 논문에서는 한국형 기동헬기의 안전영역 검증을 위해 블레이드 플래핑 각을 산출할 수 있는 근사식을 제시하였다. 블레이드의 플래핑 운동은 항공기 동체와의 충돌을 일으킬 수 있기 때문에 안전성 측면에서 검증되어야 하지만 비행 중의 플래핑 각을 정확하게 예측하거나 측정하는 것은 어려움이 있다. 이에 따라 공력이론을 활용한 코닝 각 예측 식과 개발해석결과를 활용한 동적 플래핑 각 예측 식을 도출하였다. 이 후 항공기 모사시험을 실시하여 식을 이용한 플래핑 각과 실측된 플래핑 각을 비교하여 산출식의 적절성을 확인하였다. 최종적으로 산출된 식을 이용하여 AC29 및 FAR29를 바탕으로 안전성 측면에서 검증이 요구되는 기동의 플래핑 각을 산출하여 개발에서 설정된 항공기 안전영역의 적절성을 확인하였다.

Keywords

References

  1. Helicopter, Utility, Korean defense specification 1520-4001-2, 2013.
  2. AH-KAI Engineering Coordination Memo.
  3. Federal Aviation Regulation 29 Airworthiness Standard, 29.661 Rotor Blade Clearance, 2014.
  4. Helicopter Performance, Stability, and Control, Raymond W. Prouty, 2007, pp. 171-173
  5. Federal Aviation Regulation 29 Airworthiness Standard, Subpart B Flight, 2014.
  6. Advisory Circular 29 Airworthiness Standards : Transport category rotorcraft, Subpart B Flight, 2014.