• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.9
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• pp.726-733
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• 2013

The rotor blade of helicopter is the core component determining helicopter performance and requiring low noise and low vibration because the blade becomes the major source of noise during flight. The performance analysis of candidates rotor blades is very critical because LCH(Light Civil Helicopter) will be developed parallel with LAH(Light Armed Helicopter) as an international upgrade program based on the existing platform of foreign civil helicopter. This research was aimed to recognize the performance of the candidates rotor blades compared with the newly developed foreign rotor blades and to investigate the feasibility about developing korea unique shape rotor blades by analysis the rotor performance and noise. The result of this research can be used for the target performance index during negotiation with foreign helicopter company and developing korea unique shape rotor blades.

• Current Industrial and Technological Trends in Aerospace
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• v.8 no.1
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• pp.104-111
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• 2010

This paper deals with the world civil helicopter market scope, world market analysis based on the operating fleet ages, preconditions for market entry, and market forecast which are necessary for Korean industry to enter into world market. According to the analysis, the heavy single class demand is rapidly declined. The demand is moving toward the heavier class than that operated now. Korean industry had better have strategic positioning to heavy twin and light medium twin classes. A considerable amount of Korean civil helicopter based on Surion can be sold if there are appropriate efforts for price, specification, marketing strategy and so on.

• Journal of the Korean Society of Systems Engineering
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• v.13 no.1
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• pp.7-14
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• 2017

Korea Aerospace Research Institute takes part in the vibration control software development for an Active Vibration Control System (hereafter, AVCS) for helicopters with Korea Aerospace Industries Ltd. in the Light Civil Helicopter (LCH) Project. The vibration control software is being developed per RTCA/DO-178C certification regulation and use of configuration management tools for software outputs is required. Redmine, an open source software is for issue or bug tracking and management software. Git, another open source software is a distributed version control software and is developed for Linux OS development. This paper introduces the functionalities of Redmine and Git, the reason why they are selected for the configuration management tool for the software outputs, and how they are being used for AVCS software development.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.201-204
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• 2017

An comparative analysis between two engine type certification specifications which are FAR Part 33 and EASA CS-E has been performed to provide fundamental information for validity assessment of civil certified engine when it is installed to a military rotorcraft. The analysis result has been used to build a traceability information between CS-E and MIL-HDBK-516C by which the substantiation data for engine type certification can be used as parts of aircraft propulsion system airworthiness substantiation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.3
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• pp.181-192
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• 2022

Active vibration control system(AVCS) for helicopter enables to control the vibration generated from the main rotor and has the superb vibration reduction performance with low weight compared passive vibration reduction device. In this paper, FxLMS algorithm-based vibration control software of the light civil helicopter tansmits the control command calculated using the signals of the tachometer and accelerometers to the circular force generator(CFG) is developed and verified. According to the RTCA DO-178C/DO-331, the vibration control software is developed through the model based design technique, and real-time operation performance is evaluated in PILS(processor in-the loop simulation) and HILS(hardware in-the loop simulation) environments. In particular, the reliability of the software is improved through the LDRA-based verification coverage in the PIL environments. In order to AVCS to light civil helicopter(LCH), the dynamic response characteristic model is obtained through the ground/flight tests. AVCS configuration which exhibits the optimal performance is determined using system optimization analysis and flight test and obtain STC certification.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.2
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• pp.159-166
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• 2018

In this study, the internal structural design, dynamic characteristics and load analyses of the small scaled rotor blade required for LCH(Light Civil Helicopter) main rotor wind tunnel test were carried out. The test is performed to evaluate the aerodynamic performance and noise characteristics of the LCH main rotor system. Therefore, the Mach-scale technique was appled to design the small scaled blade to simulate the equivalent aerodynamic characteristics as the full scale rotor system. It is necessary to increase the rotor speed to maintain the same blade tip speed as the full scale blade. In addition, the blade weight, section stiffness, and natural frequency were scaled according to the Mach-type scaling factor(${\lambda}$). For the design of skin, spar, torsion box, which are the main components of the blade, carbon and glass fiber composite materials were adopted, and composite materials are prepreg types that can be supplied domestically. The KSec2D program was used to evaluate the section stiffness of the blade. Also, structural loads and dynamic characteristics of the Mach scale blade were investigated through the comprehensive rotorcraft analysis program CAMRADII.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.3
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• pp.442-453
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• 2016

A significant source of vibration in helicopters is the main rotor system, and it is a technical challenge to reduce the vibration in order to ensure the comfort of crew and passengers. Several types of passive devices have been applied to conventional helicopters in order to reduce the vibration. In recent years, helicopter manufacturers have increasingly adopted active vibration control systems (AVCSs) due to their superior performance with lower weight compared with passive devices. AVCSs can also maintain their performance over aircraft configuration and flight condition changes. As part of the development of AVCS software for light civil helicopter (LCH) applications, a test bench is constructed and vibration control tests and simulations are performed in this study. The test bench, which represents the airframe, is excited using a pair of counter rotating force generators (CRFGs) and a multiple input single output (MISO) AVCS that consists of three accelerometer sensors and a pair of CRFGs; a filtered-x least mean square (LMS) algorithm is applied for the vibration reduction. First, the vibration control tests are performed with uniform sensor weights; then, the change in the control performance according to changes in the sensor weight is investigated and compared with the simulation results. It is found that the vibration control performance can be tuned through adjusting the weights of the three sensors, even if only one actuator is used.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.7
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• pp.566-573
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• 2017

A type certificate is required to ensure the safety of aircraft design. If a person is to pursue major design change to the certified aircraft, an applicant has to apply for a new type certificate, an amended type certificate, or a supplemental type certificate appropriately. Design changes to be applied for a supplemental type certificate are abstractly defined in ICAO, FAA, and EASA regulations. In this paper, authors reviewed certification procedures regarding design changes, analysed certification examples of leading countries, and presented the criteria to determine "major design changes not extensive" for a supplemental type certificate.

• 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.

• 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.