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Development of forward flight trim and longitudinal dynamic stability codes and their application to a uh-60 helicopter

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2009
Çalışkan, Sevinç
This thesis describes the development of a series of codes for trim and longitudinal stability analysis of a helicopter in forward flight. In general, particular use of these codes can be made for parametric investigation of the effects of the external and internal systems integrated to UH-60 helicopters. However, in this thesis the trim analysis results are obtained for a clean UH-60 configuration and the results are compared with the flight test data that were acquired by ASELSAN, Inc. The first of the developed trim codes, called TRIM-CF, is based on closedform equations which give the opportunity of having quick results. The second code stems from the trim code of Prouty. That code is modified and improved during the course of this study based on the theories outlined in [3], and the resultant code is named TRIM-BE. These two trim codes are verified by solving the trim conditions of the example helicopter of [3]. Since it is simpler and requires fewer input parameters, it is more often more convenient to use the TRIM-CF code. This code is also verified by analyzing the Bo105 helicopter with the specifications given in [2]. The results are compared with the Helisim results and flight test data given in this reference. The trim analysis results of UH-60 helicopter are obtained by the TRIM-CF code and compared with flight test data. A forward flight longitudinal dynamic stability code, called DYNA-STAB, is also developed in the thesis. This code also uses the methods presented in [3]. It solves the longitudinal part of the whole coupled matrix of equations of motion of a helicopter in forward flight. The coupling is eliminated by linearization. The trim analysis results are used as inputs to the dynamic stability code and the dynamic stability characteristics of a forward flight trim case of the example helicopter [3] are analyzed. The forward flight stability code is applied to UH-60 helicopter. The codes are easily applicable to a helicopter equipped with external stores. The application procedures are also explained in this thesis.