• Journal of Advanced Navigation Technology
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• v.25 no.1
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• pp.17-28
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• 2021

Recently, eVTOL, the next-generation of eco-friendly transportation, has been in the spotlight due to global warming along with traffic jams in large cities of many countries. This study benchmark the external features of Hyundai Motors S-A1, a compound eVTOL combined fixed and tilt rotors among many types of eVTOLs, to create the basic configuration using reverse design techniques. Basic configurations were created using CATIA and aerodynamic analyses were performed using the aircraft design and aerodynamic analysis programs, OpenVSP, XFLR5, and the aircraft wetted area, drag, and lift were calculated after selecting the airfoil, incidence angle, and dihedral and anhedral angles through trade study. Also, required powers were estimated for completing the given mission profile and components weight and the total weight were predicted using the estimation formula and data survey.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.15 no.4
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• pp.24-32
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• 2007

In this study, computational structural vibration analyses of a smart unmanned aerial vehicle (SUAV) with tilt-rotors due to dynamic hub loads have been conducted considering detailed supporting structures of installed equipments. Three-dimensional dynamic finite element model has been constructed for different fuel conditions and tilting angles corresponding to helicopter, transition and airplane flight modes. Practical computational procedure for modal transient response analysis is successfully established. Also, dynamic loads generated by rotating blades and wakes in the transient and forward flight conditions are calculated by unsteady computational fluid dynamics technique with sliding mesh concept. As the results of present study, transient structural displacements and accelerations of the vibration sensitive equipments are presented in detail. In addition, vibration characteristics of structures and installed equipments of which safe operation is normally limited by the vibration environment specifications are physically investigated for different flight conditions.

• Aerospace Engineering and Technology
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• v.5 no.2
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• pp.240-247
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• 2006

Tilt rotor aircraft is a multi-configuration airplane which has three independent flight modes; helicopter, conversion, and aiplane. The control surface mixer resign is reqctired to generate and distribute efficient control forces and moments in each flight mode. In the conversion mode, the thrust vector is changed from helicopter mode to airplane, therefore the thrust vector makes undesired forces and moments which affect on pitch, roll and yaw dynamics. This paper describes the design results of control surface mixer design which minimize the undesired forces and moments due to nacelles tilting angle change for 4O% scaled model.

• Journal of Advanced Navigation Technology
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• v.27 no.1
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• pp.77-95
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• 2023

In this study, the conceptual design of a tilt + stopped rotor type electric vertical take-off and landing (eVTOL) aircraft was performed using design iteration. Based on Hyundai Motor's S-A1, the mission profile was defined using the concept of urban air mobility (UAM), and configuration design and aerodynamic analysis were performed using OpenVSP and XFLR5 software. After estimating the required power for the designed eVTOL, the required performance of the battery and the maximum take-off weight (MTOW) were calculated. . It was iteratively calculated using Microsoft Excel and Visual Basic Application, and a new electric motor weight estimation formula was derived. Also, the sensitivity analyses of each design variables of an eVTOL was performed using the automated program.

• Journal of Aerospace System Engineering
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• v.18 no.1
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• pp.29-36
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• 2024

Recently, the concept of Urban Air Mobility (UAM) has expanded to Advanced Air Mobility (AAM). A tilt rotor type of vertical take-off and landing aircraft has been actively studied and developed. A tilt-rotor aircraft can perform a transition flight between vertical and horizontal flights. A blade pitch angle control system can be used for flight stability during transition flight time. In addition, Individual Blade Control (IBC) can reduce noise and vibration generated in transition flight. This paper proposed Disturbance Observer Based Control (DOBC) and Time Delay Control (TDC) for individual blade control of an Electro-Mechanical Actuator (EMA) based blade pitch angle control system. To compare and analyze proposed controllers, numerical simulations were conducted with DOBC and TDC.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.513-518
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• 2004

KARI(Korea Aerospace Research Institute) has developed smart unmaned aerial vehicle(UAV) since 2002. Smart UAV has tilt rotor configuration which can take off and land vertically. For designing and developing smart UAV, it is necessary to obtain design loads. ARGON which use the panel method is multidisciplinary aircraft design program developed and modified by KARI and TsAGI. Panel method is very useful to obtain aerodynamic loads, so it have been used widely for aircraft loads analysis. For flight loads analysis, we have to prepare regulations and load conditions, and then design aerodynamic panel model, mass model and structure model. In this paper, we introduce the flight loads analysis procedure briefly, and show the smart UAV loads analysis procedure and result using ARGON.

• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.254-262
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• 2008

Several decades have passed since tiltrotor technology became a hot issue of debates between aircraft majors, policy maker and mass-media. Although most of those subjects have been officially probed or answered in objective way, biased articles or argues related with the adequacy of this technology still prevail in the way of tilt-rotor development programs, which are totally irrelevant and out-dated. This paper aims to help understanding on those issues in technically balanced manner and the cases of flight test mishaps.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.6
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• pp.63-69
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• 2011

The Smart UAV must have the control characteristics of propulsion system necessary for both rotary aircraft and fixed wing aircraft though it equips turbo-shaft engine. To develop an electronic engine controller in the future, it is necessary to accumulate the experience of engine operation and data of tilt rotor aircraft. For this purpose, the computer programs which predict engine performance in the steady state and transient state can be utilized for the supplementation of flight test data. In this work, we developed a dynamic analysis program using engine performance data gathered during the flight tests. In addition the accuracy of the program was verified through comparison with flight test data and the results of steady-state performance analysis program.

• Aerospace Engineering and Technology
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• v.9 no.1
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• pp.1-8
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• 2010

The tilt-rotor Smart UAV(Unmanned Air Vehicle) has been developed by KARI(Korea Aerospace Research Institute) for civil purposes. In order to prove the reliabilities of total system of Smart UAV, the series of ground tests were performed including system interface test, aircraft HILS(Hardware In the Loop Simulation) Test, ground power test, 4-DOF (Degrees of Freedom)rig test, and tethered hover test. Many unexpected problems occurred at each ground test. With clearing these problems, the total Smart UAV systems were matured and the airworthiness was proven enough. After complete of additional ground test proposed by FRRB(Flight Readiness Review Board), the first flight test will be performed in this year. This paper presents the procedures and the analysis results of the ground tests for the tilt-rotor Smart UAV.

• 한국전산유체공학회:학술대회논문집
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• 2004.03a
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• pp.27-34
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• 2004

In the Smart UAV Development Program, one of the 21c Frontier R&D Program, the tiltrotor has been studied as the concept of vehicle. The tiltrortor aircraft take-off and land in rotary wing mode like conventional helicopter, and cruise in fixed wing mode like conventional propeller airplane. For the conversion of the flight mode from helicopter to airplane, the nacelle located at wing tip has to be tilted from about 90 degrees of helicopter mode to about 0 degree of airplane mode. In this study, the aerodynamic characteristics of the wing with tilted nacelle is investigated using computation fluid dynamics technique. In order to feature out aerodynamic interferences between wing and nacelle, the flow calculations are conducted for the wing and the nacelle separately and for the combined geometry of wing and nacelle, respectively. Through this computations, not only the aerodynamic data-base for the wing-nacelle is constructed but also its contribution to the configuration design of the wing-nacelle is anticipated.