• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.508-512
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• 2004

This paper described operation and vibration characteristics of 'Tail-Fan' performance test system. KARI(Korea Aerospace Research Institute) developed 'Tail-Fan' system as a kind of helicopter anti-torque system(ATS) and designed ATS performance test-rig for Tail-Fan system performance test. Test-rig consists of driving parts, supporting parts and rotating parts. For Tail-Fan system performance tests, firstly, test-rig operation tests were carried out for verification of design specifications. Secondly, natural frequencies of fan blade and test-rig were measured respectively. Lastly, to find the operation rotating speed for performance tests, vibration tests using accelerometers on tail gear box(TGB) were carried out. Through the fanplot and vibration test results, Tail-Fan performance test conditions to avoid a resonance were found and performance tests were well done safely.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11b
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• pp.41-44
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• 2005

This paper described improvement and operation of a 'Tail-Fan' anti-torque performance test system KARI (Korea Aerospace Research Institute) developed a 'Tail-Fan' anti-torque system of a helicopter and a performance test-rig to test the performance of the Tail-Fan. The test-rig was improved for full rotating test in 4300rpm(100%). Machinery and hydraulic parts ware changed to reduce vibration and to increase safety. To find the operation rotating speed for the performance test, vibration test were carried out rising accelerometers on tail gear box. The performance test conditions of the Tail-Fan to avoid a resonance were found from vibration test results. The Tail-Fan operation tests were performed safely frier to carry out performance test.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.4 s.97
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• pp.421-428
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• 2005

This paper described operation and vibration characteristics of a 'tail-fan' anti-torque performance test system. KARI (Korea Aerospace Research Institute) developed a 'tail-fan' anti-torque system of a helicopter and a performance test-rig to test the performance of the tail-fan. The performance test-rig consists of driving, supporting and rotating parts. In the process of the performance test, firstly, operation test of the test-rig were carried out to verify design specifications. Secondly, natural frequencies of fan blade and test-rig were measured respectively. Lastly, to find the operation rotating speed for the performance test, vibration test were carried out using accelerometers on tail gear box. The performance test conditions of the tail-fan to avoid a resonance were found from the fan-plot and vibration test results. The tail-fan performance tests were well done safely.

• Aerospace Engineering and Technology
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• v.4 no.2
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• pp.50-59
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• 2005

This paper described performance test of 1st prototype "Tail-Fan" system. KARI(Korea Aerospace Research Institute) developed "Tail-Fan" system as a kind of helicopter anti-torque system(ATS) and designed ATS performance test-rig for Tail-Fan system performance test. For Tail-Fan system performance tests, firstly, test-rig operation tests were carried out for verification of design specifications. And natural frequencies of fan blade and test-rig were measured respectively. To find the operation rotating speed for performance tests, vibration tests using accelerometers on tail gear box(TGB) were carried out. Through the fanplot and vibration test results, rotational speed for Tail-Fan performance test to avoid a resonance were found and performance tests were carried out in flight conditions. We analyzed test data by non-dimensionalization. Through this results, 1st prototype "Tail-Fan" system was satisfied with design requirements.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.123-126
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• 2003

This paper describes the development procedure for Tail-Fan system which has the role of anti-torque and yaw control in helicopter. A detailed design of Tail-Fan system was done and structural analysis also was done. After finishing detailed design, Detailed drawings were generated for manufacture. Through detailed design and manufacture, required techniques were achieved for helicopter development. After validation through performance and stability test, acquired techniques will be applied to development of Korea Multi-role Helicopter(KMH) which will be launched

• International Journal of Aeronautical and Space Sciences
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• v.6 no.1
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• pp.89-96
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• 2005

Ducted fans have advantages in noise as well as operational safety aspects compared to conventional tail rotors and are used as an anti-torque system for various classes of helicopters. The final goal of this study is to develop a ducted fan anti-torque system which can replace conventional tail rotors of existing helicopters to achieve safety enhancement and low noise level. In this paper, a conceptual design process and the results are described. Initially, the design requirement and the design parameter characteristics are analysed, and then initial sizing and configuration design are performed. There are several configuration changes due to specific technical reasons in each case. Finally, the required power and the pitch link load are predicted as an initial estimation. The conceptual design technique for the ducted fan in this study can be easily applied to the design of other ducted fans such as the lift fan for unmanned aerial vehicle.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.690-695
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• 2006

This paper described the Performance test and sound characteristics of helicopter 'Tail-Fan' anti-torque system. In this research, Korea Aerospace Research Institute(KARI) developed 'Tail-Fan' anti-torque system for a helicopter and carried out performance and sound capturing tests of even and uneven tail fans. The performance test is carried out and the noise signals which are generated during the test are saved with microphones at the same time. The performance test's results meet the design requirements. Tone-corrected perceived noise level is reduced by replacing the even product with the uneven one.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.8 s.113
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• pp.857-863
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• 2006

This paper described the performance test and sound characteristics of helicopter 'Tail-Fan' anti-torque system. In this research, Korea Aerospace Research Institute(KARI) developed 'Tail-Fan' anti-torque system for a helicopter and carried out performance and sound capturing tests of even and uneven tail fans. The performance test is carried out and the noise signals which are generated during the test are saved with microphones at the same time. The performance test's results meet the design requirements. Tone-corrected perceived noise level is reduced by replacing the even product with the uneven one.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.5
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• pp.9-17
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• 2005

In the early stage of helicopter design, an optimal configuration is usually determined after a numerous parametric study about the aerodynamic performance due to geometric variation. In order to improve the aerodynamic performance of a shrouded tail rotor, optimization of the tip clearance gap between blade and shroud, the blade planform shape, and the arrangement of blade spacing is required. In the present study, the aerodynamic performance characteristics of a shrouded tail rotor due to geometric variation was investigated by using an inviscid compressible unstructured mesh flow solver for rotary wings.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.5
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• pp.1-9
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• 2003

Detailed flow of a shrouded tail rotor in hover is studied by using a compressible inviscid flow solver on unstructured meshes. The numerical method is based on a cell-centered finite-volume discretization and an implicit Gauss-Seidel time integration. Numerical simulation is made for a single blade attached to the center body and guide by the duct by imposing a periodic boundary condition between adjacent rotor blades. The results show that the performance of an isolated rotor without shroud compares well with experiment. In case of a shrouded rotor, correction of the collective pitch angle is made such that the overall performance matches with experiment to account for the uncertainties of the experimental model configuration. Details of the flow field compare well with the experiment confirming the validity of the present method.