• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.1
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• pp.75-84
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• 2021

The authors had presented two previous papers[1,2] on Helicopter/Rotorcraft develoment in Europe and US. Meanwhile, the next generation rotorcrafts, currently under development in US and Europe, have new configurations (tilt-rotor, coaxial, compound) of rotor-type vertical takeoff/landing rotorcrafts to overcome the disadvantages of traditional helicopters. For developing these new types of rotorcrafts, the upgraded conceptual design/comprehensive programs are required. In US and Europe, they are already developing new program tools with their technologies and database obtained during more than last half centuries. For us, many academia, research institutes and industrial engineers have experienced and developed core technologies on rotorcrafts (aerodynamics, structural analysis, flight dynamics, and noise analysis etc.) comparable to US and Europe during last couple of decades of developing helicopters and various configurations of rotorcrafts. In this paper, the pros and cons of conceptual design/comprehensive tools currently used in US and Europe have been summarized. Furthermore, the possibilities and problems to develope our own design and analysis tools have been studied.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.9
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• pp.671-680
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• 2020

This paper describes an improved beam analysis for compound rotorcraft fuselage design. The present beam approach is capable of analyzing fuselage composed of stiffeners using equivalent layer methodology. Thickness of the skin and laminated layer approach are suggested based on the unified beam formulation. The analysis which considers an equivalent stiffener layer is performed for a fuselage with stiffeners and preliminary study about the specification of stiffeners is conducted and compared by the results using the existing software.

• Journal of Aerospace System Engineering
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• v.13 no.6
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• pp.52-59
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• 2019

The rotor blade is a key component that generates the lift, thrust, and control forces required for helicopter flight by the torque transmitted through the hub and the blade pitch angle control, and should be designed to factor vibration characteristics so that there is no risk of resonance with structural safety. In this study, the structural design of the main rotor blade for MPUH(Multi-Purpose Unmanned Helicopter) was conducted and the sectional stiffness measurement of the fabricated blade was performed. The evaluation of the vibration characteristics of the main rotor system was then conducted factoring the measured stiffness distribution. The interior of the rotor blade comprised of the skin, spar, and torsion box, and carbon and glass fiber composites were applied. The Ksec2D program was applied to predict the stiffness of blade, and the results were compared to the measured data. CAMRADII, a comprehensive rotorcraft analysis program, was applied to investigate the natural frequency trends and resonance risks due to the rotor rotation.

• 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.