• Title/Summary/Keyword: Pitot-Static System

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Study on Flight Test Practice of the Small Civil Airplane Development for Pitot-Static System's Error Identification (소형 항공기 개발 동정압계통 오차 확인 비행시험 사례)

  • Kim, Chanjo;Seo, Jihan;Lee, Wonjoong
    • Journal of Aerospace System Engineering
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    • v.7 no.3
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    • pp.33-38
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    • 2013
  • The air data measured from the static pressure, the dynamic pressure and etc. of an airplane is used for calculation of many flight parameters(altitude and airspeed and so on) and these values applied to flight safety and navigation flight. The pitot-static system of the development airplane is calibrated by finding of pitot-static system's error using tower fly-by, trailing cone method and etc. This paper is describing for the introduction of the trailing cone method and major items for test planning, preparation, operation and results for air data calibration flight test performed, considering efficiency and safety during KC-100 development project.

Design of Pitot-Tube Configuration Using CFD Analysis and Optimization Techniques (CFD 해석 및 최적화 기법을 이용한 피토관 형상설계)

  • Kim, Do-Jun;Cheon, Young-Seong;Myong, Rho-Shin;Park, Chan-Woo;Cho, Tae-Hwan;Park, Young-Min;Choi, In-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.32 no.5
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    • pp.392-399
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    • 2008
  • Accurate measurement of speed and altitude of flying vehicles in air data system remains a critical technical issue. A highly reliable Pitot-static probe is required to obtain air data such as total pressure and static pressure. In this study, an analysis of the characteristics of flowfield around the Pitot-static probe was performed by using a Navier-Stokes CFD code. In addition, for the purpose of finding an optimal configuration, a technique based on the response surface method is applied to the problem with design parameters including shape of the nose section and cone angle. It is shown that the optimal configuration fulfills the MIL specification in wider range of high angles of attack.

Study on Static Pressure Error Model for Pressure Altitude Correction (기압 고도의 정밀도 향상을 위한 정압 오차 모델에 관한 연구)

  • Jung, Suk-Young;Ahn, Chang-Soo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.4
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    • pp.47-56
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    • 2005
  • In GPS/INS/barometer navigation system for UAV, vertical channel damping loop was introduced to suppress divergence of the vertical axis error of INS, which could be reduced to the level of accuracy of pressure altitude measured by a pitot-static tube. Because static pressure measured by the pitot-static tube depends on the speed and attitude of the vehicle, static pressure error models, based on aerodynamic data from wind tunnel test, CFD analysis, and flight test, were applied to reduce the error of pressure altitude. Through flight tests and sensitivity analyses, the error model using the ratio of differential pressure and static pressure turned out to be superior to the model using only differential pressure, especially in case of high altitude flight. Both models were proposed to compensate the effect of vehicle speed change and used differential and static pressure which could be obtained directly from the output of pressure transducer.

Uncertainty Assessment of Gas Flow Measurement Using Multi-Point Pitot Tubes (다점 피토관을 이용한 기체 유량 측정의 불확도 평가)

  • Yang, Inyoung;Lee, Bo-Hwa
    • The KSFM Journal of Fluid Machinery
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    • v.19 no.2
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    • pp.5-10
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    • 2016
  • Gas flow measurement in a closed duct was performed using multi-point Pitot tubes. Measurement uncertainty was assessed for this measurement method. The method was applied for the measurement of air flow into a gas turbine engine in an altitude engine test facility. 46 Pitot tubes, 15 total temperature Kiel probes and 9 static pressure tabs were installed in the engine inlet duct of inner diameter of 264 mm. Five tests were done in an airflow range of 2~10 kg/s. The flow was compressible and the Reynolds numbers were between 450,000 and 2,220,000. The measurement uncertainty was the highest as 6.1% for the lowest flow rate, and lowest as 0.8% for the highest flow rate. This is because the difference between the total and static pressures, which is also related to the flow velocity, becomes almost zero for low flow rate cases. It was found that this measurement method can be used only when the flow velocity is relatively high, e.g., 50 m/s. Static pressure was the most influencing parameter on the flow rate measurement uncertainty. Temperature measurement uncertainty was not very important. Measurement of boundary layer was found to be important for this type of flow rate measurement method. But measurement of flow non-uniformity was not very important provided that the non-uniformity has random behavior in the duct.

Study on PEC Flight Test Techniques for Small Airplane (소형비행기 동정압 시스템 보정을 위한 비행시험방안 연구)

  • Kim, Phil-Soo
    • Journal of Aerospace System Engineering
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    • v.5 no.2
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    • pp.1-7
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    • 2011
  • On this study, applicable aircraft pitot-static system airworthiness requirements and flight test techniques for PEC(Position Error Correction) to KAS Part 23 airworthiness standards are introduced. Also, pros and cons, applicable test conditions, test procedures and required test parameters of each flight test techniques are reviewed on this study.

An Experimental Study on Energy Losses in Steam Turbine Cascade Flow (증기터빈 익렬유동의 에너지손실에 관한 실험적 연구)

  • ;;Ahn, Hyung-Joon;Lee, Kwon-Hee
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.11
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    • pp.3022-3030
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    • 1995
  • The irreversibility of condensation process in the supersonic flow of steam turbine cascade causes the entropy to increase and the total pressure loss to be generated. In the present study, in order to investigate the moist air flow in two dimensional steam turbine cascade made as the configuration of the last stage tip section of the actual steam turbine moving blade, the static and total pressures along suction side of the blade are measured by pressure taps and Pitot tube. The flow field is visualized by a Schlieren system. The effects of stagnation temperature and the degree of supersaturation on energy loss and entropy change in the flow are clearly identified.

The Study of Aerodynamic Characteristics of Ram-jet with Different Intake (서로 다른 램제트 흡입구에 따른 공기역학적 특성 연구)

  • Park, Soon-Jong;Park, Jong-Ho
    • Journal of the Korean Society of Propulsion Engineers
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    • v.14 no.6
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    • pp.9-16
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    • 2010
  • The SFRJ(Solid Fuel Ram-Jet) propulsion is attractive for projectiles because of the combination of high propulsive performance and low system complexity more than conventional projectiles. The Objective of this research was to characterize the inlet aerodynamic characteristics (center-body & pitot type) in SFRJ. Diffuser static pressure & combustion chamber pressure was tested and the AoA was changed $0^{\circ}$ and $4^{\circ}$ at Mach number of 3.0 for performance estimate. The performance study of inlet was carried out with the Schlieren system and Supersonic cold-flow system. Under mach 3.0, the center-body showed twice higher total pressure recovering ratio than the pitot type. A Computational fluid dynamic solution is applied internal flow of inlet and the solutions are compared with experimental results.

Wind and Airspeed Error Estimation with GPS and Pitot-static System for Small UAV

  • Park, Sanghyuk
    • International Journal of Aeronautical and Space Sciences
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    • v.18 no.2
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    • pp.344-351
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    • 2017
  • This paper presents a method to estimate steady wind and airspeed bias error using an aircraft with GPS and airspeed sensor. The estimation uses the vector relation between the inertial, air, and wind velocities through a novel design of an extended Kalman filter. The observability analysis is also presented to show that the aircraft is required to keep changing its flight direction for the desired observability. The feasibility and performance of the proposed algorithm is demonstrated through simulations and flight experiments.

Mach 5 Performance Tests of Scramjet Engine Intake Using Free-jet Type Ground Propulsion Test Facility (자유제트형 지상추진 시험설비를 사용한 스크램제트 엔진 흡입구의 마하 5 성능시험)

  • Lee, Yang Ji;Yang, Inyoung;Lee, Kyung Jae;Oh, Jung Hwan;Choi, Jin
    • Journal of the Korean Society of Propulsion Engineers
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    • v.26 no.4
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    • pp.10-20
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    • 2022
  • The performance analysis test of the scramjet engine intake was conducted under the Mach 5 condition of the scramjet engine test facility, a free-jet ground test facility of the Korea Aerospace Research Institute. A pitot/static pressure rake installed at the rear of the isolator was designed and manufactured to measure the total pressure recovery rate and mass capture ratio, which are typical performance factors of the scramjet engine intake. The effect of the rake mounted at the rear of the isolator on the intake, the performance analysis measured by the rake, and the change in wall static pressure distribution according to the angle of attack were performed. Finally, the point at which the intake unstart occurred was confirmed by using the rear back pressure adjusting device, which simulates pressure rise in the combustor, and the results are summarized in this paper.

Uncertainty Assessment of a Towed Underwater Stereoscopic PIV System (예인수조용 스테레오스코픽 입자영상유속계 시스템의 불확실성 해석)

  • Seo, Jeonghwa;Seol, Dong Myung;Han, Bum Woo;Yoo, Geuksang;Lim, Tae Gu;Park, Seong Taek;Rhee, Shin Hyung
    • Journal of the Society of Naval Architects of Korea
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    • v.51 no.4
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    • pp.311-320
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    • 2014
  • Test uncertainty of a towed underwater Stereoscopic Particle Image Velocimetry (SPIV) system was assessed in a towing tank. To estimate the systematic error and random error of mean velocity and turbulence properties measurement, velocity field of uniform flow was measured. Total uncertainty of the axial component of mean velocity was 1.45% of the uniform flow speed and total uncertainty of turbulence properties was 3.03%. Besides, variation of particle displacement was applied to identify the change of error distribution. In results for variation of particle displacement, the error rapidly increases with particle movement under one pixel. In addition, a nominal wake of a model ship was measured and compared with existing experimental data by five-hole Pitot tubes, Pitot-static tube, and hot wire anemometer. For mean velocity, small local vortex was identified with high spatial resolution of SPIV, but has serious disagreement in local maxima of turbulence properties due to limited sampling rate.