• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.8
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• pp.806-812
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• 2010

Fuel tanks for rotorcraft have a great influence on the survivability of crews. The philosophy of crashworthy rotorcraft design evolved from the long term effort of the US Army. US army established MIL-DTL-27422D for specifying detail requirements related to crash resistant fuel tank especially for military rotorcraft to prevent post crash fire which is the greatest threat to life in rotorcraft crash. Crashworthiness of the rotorcraft fuel tank could be guaranteed through the crash impact tests which are specified in the MIL-DTL-27422D. Fuel tanks for Korea Helicopter Program have been developed and tested according to MIL-DTL-27422D with minor modifications of flexible fittings. The present study shows some results of the mandatory crash impact tests of the fuel tanks to verify their performances.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.5
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• pp.477-481
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• 2010

Some rotorcraft fuel tanks are required to be self-sealing and crashworthy for enhancing the survivability of crews. Self-sealing capability prevents the fuel leakage through contacting fuel with self-sealing material when the tank wall is penetrated by projectiles such as bullets. US army established MIL-DTL-27422D which specifies the detail requirements related to gunfire resistant fuel tank especially for military rotorcraft. The Fuel tanks for Korea Helicopter Program have been developed in accordance with MIL-DTL-27422D. The Self-sealing capability of the fuel tanks has been confirmed by the gunfire resistance test which specified on the MIL-DTL-27422D.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.5
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• pp.343-349
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• 2013

Crashworthy fuel cells have a great influence on improving the survivability of crews. Since 1960's, the US army has developed a detailed military specification, MIL-DTL-27422, defining the performance requirements for rotorcraft fuel cells. In the qualification tests required by MIL-DTL-27422, the crash impact test should be conducted to verify the crashworthiness of fuel cell. Success of the crash impact test means the improvement of survivability of crews by preventing post-crash fire. But, there is a big risk of failure due to huge external load in the crash impact test. Because the crash impact test itself takes a long-term preparation efforts together with costly fuel cell specimens, the failure of crash impact test can result in serious delay of a entire rotorcraft development. Thus, the numerical simulations of the crash impact test has been required at the early design stage to minimize the possibility of trial-and-error with full-scale fuel cells. Present study performs the numerical simulation using SPH(smoothed particle hydro-dynamic) method supported by a crash simulation software, LS-DYNA. Test condition of MIL-DTL-27422 is reflected on analysis and material data is acquired by specimen test of fuel cell material. As a result, the resulting equivalent stresses of fuel cell itself are calculated and vulnerable areas are also evaluated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1054-1060
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• 2013

Fuel tank of a rotorcraft has a great influence on the survivability of crews. For a long time, US army has tried to develop the proper material for fuel cell of a military rotorcraft. As a result, the design specification of fuel cell, MIL-T-27422A, was issued for the first time on 1961. Through a few revisions, it has been developed to ML-DTL-27422D in 2007. It should be assured that fuel cell satisfies the requirement defined in MIL-DTL-27422D. The qualification test of this specification is classified into Phase I test for material and Phase II for fuel cell itself. This paper studies test conditions and procedures of slosh & vibration, gunfire resistance and crash impact test. They are considered as the most important tests which have a high possibility of failure. The rational consideration of this paper can improve the ability for estimating not only the validity of test procedure and test condition but test result. Based on the rational consideration, it is expected that the ability of the systematic development can be improved.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.1
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• pp.62-68
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• 2011

Rapid turning and accelerated movement of a rotorcraft leads to the slosh and vibration effect of fuel in the fuel tank. Due to the slosh load, the internal component of a fuel tank can be broken and fuel tank skin can be damaged. This is directly related to human survivability. Military specification(MIL-DTL-27422D) requires the verification of the stability of aircraft fuel tank and internal component against slosh & vibration load through the qualification test. This report shows the establishment of slosh and vibration test facility and KUH fuel tank qualification test result.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.687-693
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• 2016

The rapid turning and acceleration movement of a rotorcraft leads to a sloshing phenomenon in the fuel tank. Sloshing caused by rapid movement can affect the internal components by creating an excessive load. In severe situations, the resulting damage to the internal components and pipes can also lead to the tearing of the fuel tank itself. Therefore, to improve the survivability of the crew, the internal components of the fuel tank must be designed to retain their structural soundness during the sloshing phenomenon. In order to accomplish this, the sloshing load acting on the components first needs to be determined. This paper investigates the sloshing load applied to the internal components by performing numerical analysis for rotary-wing aircraft fuel tanks in the sloshing test. Fluid-Structural Interaction (FSI) analysis based on smoothed particle hydrodynamics (SPH) is conducted and the conditions specified in the US military standard (MIL-DTL-27422D) are employed for the numerical simulation. Based on this numerical simulation, by analyzing the load applied to the internal components of the fuel tank due to the sloshing phenomenon, the possibility of obtaining the design data by numerical analysis is examined.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.5
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• pp.521-530
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• 2011

Since aircraft fuel tanks have many interfaces connected to the airframe as well as the fuel system, they have been considered as one of the system-dependent critical components. Crashworthy fuel tanks have been widely implemented to rotorcraft and rendered a great contribution for improving the survivability of crews and passengers. Since the embryonic stage of military rotorcraft history began, the US army has developed and practised a detailed military specification documenting the unique crashworthiness requirements for rotorcraft fuel tanks to prevent most, hopefully all, fatality due to post-crash fire. The mandatory crash impact test required by the relevant specification, MIL-DTL-27422D, has been recognized as a non-trivial mission and caused inevitable delay of a number of noticeable rotorcraft development programs such as that of V-22. The crash impact test itself takes a long-term preparation efforts together with costly fuel tank specimens. Thus a series of numerical simulations of the crash impact test with digital mock-ups is necessary even at the early design stage to minimize the possibility of trial-and-error with full-scale fuel tanks. In the present study the crash impact simulation of a few fuel tank configurations is conducted with the commercial package, Autodyn, and the resulting equivalent stresses and internal pressures are evaluated in detail to suggest a design improvement for the fuel tank configuration.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.713-716
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• 2010

Slosh and vibration effects of fuel inside of fuel tank can be occurred due to the acceleration and flight speed during the rotorcraft flight. It can lead to the failure of internal fuel component and fuel tank skin can be damaged. This is directly related to human survival. Military specification (MIL-DTL-27422D) specifies that stability of aircraft fuel tank and internal component against slosh &vibration load shall be verified through the qualification test procedures. This report shows the establishment of slosh and vibration test facility and KUH fuel tank qualification test result.

• Proceedings of the KAIS Fall Conference
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• 2010.05b
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• pp.1173-1176
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• 2010

회전익 항공기의 연료탱크는 피탄으로 인해 연료 누유시 발생할 수 있는 화염으로부터 기체와 승무원의 생존성을 높이기 위하여 연료누설을 차단하는 자기밀폐 기능이 필수적으로 요구된다. 자기밀폐 기능은 내부에 적층된 자기밀폐 소재가 누설되는 연료와 화학반응을 일으켜 급속히 팽창됨으로써 피탄부를 막아, 연료누설을 차단하는 역할을 한다. 본 연구는 미군사규격(MIL-DTL-27422D) 기준으로 국내에서 제작 및 수행한 회전익 항공기의 연료탱크 자기밀폐 성능시험 평가 결과를 제시한다.

• Journal of Aerospace System Engineering
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• v.2 no.2
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• pp.14-19
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• 2008

This paper presents the procedure and the results of the preliminary design of the fuel tank as a part of developing the helicopter. For the requirements of operational capability, MIL-DTL-27422D and Defence Standard 15-2/Issue 1 are considered to be applied in developing a helicopter fuel tank. The procedure of the fuel tank development is set up including interface plate design, tank design, former design, tank material lay-up, and tank installation assessment. The outer moulded line and fittings of fuel tank have being designed, and several test will be performed to get the qualification.