• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.35 no.7
• /
• pp.575-580
• /
• 2007

During the conceptual design phase of a canard type high maneuverable aircraft, the low speed small scale wind tunnel test was conducted to investigate the high angle-of-attack static stability of the aircraft. In this study, 1/50th scale generic canard-body-wing model was used for the small scale wind tunnel test. For the analysis of static stability including high angle-of-attack nonlinear characteristics, the vertical tail effects were studied due to canard deflections. In addition, the nose chine effects were studied at high angle-of-attack. Based on the results obtained from the experimental study, the configuration change effects for canard type aircraft on high angle-of-attack static stability have been able to analyze.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.32 no.8
• /
• pp.129-137
• /
• 2004

A small size - low priced supersonic wind tunnel of which test section size is 30mm by 35.6mm and run time is 20sec is developed. This educational supersonic wind tunnel is an intermittent blowdown type with an exchangeable nozzle block. In this study, the proper sized and low priced commercial parts are used to reduce the total cost of supersonic wind tunnel. A nozzle design and small supersonic wind tunnel design process has been established, and it is confirmed that a given supersonic flow field has been obtained and proved by experiment.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.11a
• /
• pp.777-780
• /
• 2011

The supersonic wind tunnel is a common facility to studies the aerodynamic phenomenon around the high speed vehicle or weapon system whose operating speed is greater than sonic speed. In this study, a design procedure and selecting the components of a new supersonic wind tunnel whose nozzle exit is $125mm{\times}100mm$ is considered. An operating test of this wind tunnel is being conducted to compare the result with the design values, mach number, etc.

• 한국항공운항학회:학술대회논문집
• /
• 2005.05a
• /
• pp.135-138
• /
• 2005

• Journal of Bio-Environment Control
• /
• v.29 no.1
• /
• pp.73-79
• /
• 2020

The objective of this study is to analyze the heat transfer loss of covering materials in a single-span plastic greenhouse under the steady-state wind environment. To achieve this objective, the following were conducted: (1) design of a small-scaled wind tunnel (SCWT) to analyze heat losses of the greenhouse and its performance; (2) determination of the overall heat transfer coefficient (OHTC) for the covering materials using a small-scaled greenhouse model. The SCWT consists of the blowing, dispersion, steady flow, reduction and testing areas. Each part of the SCWT was customized and designed to maintain air flow at steady state and to minimize the variances in the SCWT test. In this study, the OHTCs of the covering materials were calculated by separating each with the roof, side wall, front and back of the small-scaled greenhouse model. The results of this study show that the OHTC of the roof increases as wind speed increases but the zones in which the increase rate of the OHTC decreased, were distinguished by wind tunnel wing speed of 2 ms^-1. For the side wall, the increase rate of the OHTC was particularly higher in the 0-1 ms^-1 zone.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.05a
• /
• pp.251-256
• /
• 2008

The experimental analysis on a ducted fan for the propulsion system of a small UAV were performed. To investigate the aerodynamic characteristics of the ducted fan, flow fields at inlet and outlet were measured using a hot-wire anemometry. Thrusts were measured with the six-component balance with due regard to the cross wind. To reproduce the cross wind effect, the ducted fan was aligned to $90^{\circ}$ rotated direction against flow direction in the wind tunnel. In this paper, the variation of the flow fields and thrust according to the cross wind were analyzed.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.24 no.5
• /
• pp.56-64
• /
• 2020

A wind tunnel test of 29.7% scaled model of NASA Common Research Model was performed in small low speed wind tunnel. The wind tunnel model was fabricated in Aluminium in consultation with NASA Langley Research Center and AIAA Drag Prediction Workshop committee members. The static aerodynamic forces and moments were measured at a relatively low Reynolds number of 0.3 × 10⁶ due to tunnel capability limitations. Pitching moment of three types of model support(Fin sting, Blade sting and Belly sting) were compared. The pitching moment for corrected Belly sting and Fin sting were similar. The result of pitching moment for Blade sting was very small.

• Journal of Aerospace System Engineering
• /
• v.11 no.6
• /
• pp.10-16
• /
• 2017

In order to improve the safety of the multi-copter, Korea Aerospace Research Institute (KARI) performed a wind-tunnel test using an octocopter with the maximum takeoff weight (MTOW) of 28 kg. The wind-tunnel test was performed with three different RPM ranges, 3,500, 4,500 and 5,500 rpm, and three different wind speeds, 3.5, 5 and 7 m/sec. The tested range of the angle of attacks was $-40^{\circ}$ to $20^{\circ}degree$ and ${\pm}90^{\circ}degree$. Vortex ring state (VRS) of the tested multi-copter was located around the vertical descending speed of 6 m/sec and the decrement of thrust was about 13 % at the time of testing. Compared with the single propeller wind-tunnel test result, the propeller efficiency of the octocopter dropped to 10 to 15% depending on the propeller RPM. It is hypothesized that the obtained aerodynamic characteristics by the wind-tunnel test will be used to improve the performance and wind resistance of the multi-copter.

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

• Journal of Aerospace System Engineering
• /
• v.13 no.1
• /
• pp.11-17
• /
• 2019

In this paper, the performance of a small fixed wing unmanned aerial vehicle is predicted theoretically with the minimum specifications and a low Reynolds number. Based on the results, it was compared with the results of an actual flight test and simple electric motor wind tunnel test. As a result of the validity of the analysis, a 3.5 kilograms class fixed wing small UAV can predict aerodynamic performance by general theory analysis. However, the required thrust was analyzed as a possible design error. Based on the results of this study, this paper proposed a method to minimize the design error when developing small fixed wing UAV flying in a low Reynolds number.