• Current Industrial and Technological Trends in Aerospace
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• v.7 no.2
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• pp.95-105
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• 2009

Fuel cells are applied to the propulsion system of aircraft based on environmental-friendly characteristics with low noise and zero emission of CO2, currently many kinds of UAV and small manned aircraft equipped with fuel cells are being developed. Fuel cells for aircraft typically classified into PEMFC(Proton Exchange Membrane Fuel Cell) type and SOFC(Solid Oxide Fuel Cell) type and the system is developed to adapt missions and operational conditions of aircraft. For UAV, various types of aircraft mostly based on PEM fuel cell technology are investigated for military or commercial uses, and the stability and endurance of system will be improved. For small manned aircraft, many researches are carried out to substitute the propulsion system by fuel cell, also some developments for the higher performance of APU of large commercial aircraft to apply fuel cells are in progress. In the future, a fuel cell aircraft will be expected to improve the reliability and efficiency with higher power density.

• Transactions of the Korean hydrogen and new energy society
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• v.29 no.6
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• pp.587-595
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• 2018

Recently, research is being conducted to use a fuel cell as a power source of unmanned aircraft. However, safety standards about applying fuel cells to unmanned aircraft are insufficient. In this paper, to improve the safety of the fuel cells for unmanned aircraft is experimentally studied. For this reason, standards for safety of fuel cells were analyzed. And influence of vibration among the evaluation items related to the safety of the fuel cell for unmanned aircraft was discussed. In order to, at constant intervals, vibration was applied to the fuel cell, then the performance was measured, the measurement items were gas tightness, polarization curve, frequency response analysis (FRA). A total of 220 hours was experimented at 20 hour intervals. the result of vibration test, gas leakage rate was a maximum of -0.04826 kPa/min and Polarization curve reached a maximum of 1.0103 times of the initial value, the charge transfer resistance reached a maximum of 1.0104 times of the initial value. This research indicate that performance of fuel cell is affected by vibration and this study is expected to contribute to the safety of fuel cell for unmanned aircraft.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.1
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• pp.108-117
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• 1995

The primary purpose of this extensive test effort was to observe real-time operational performance characteristics associated with automotive grade fuel utilized by piston engine powered light aviation aircraft. In fulfillment of this effort, baseline engine operations were established with 100LL aviation grade fuel followed by four blends of automotive grade fuel. A comprehensive sea-level-static test cell/flight test data collection and evaluation effort were conducted to review operational characteristics of a carbureted light aircraft piston engine as related to fuel volatility, fuel temperature, and fuel system pressure. Presented herein are results, data, and conclusions drawn from test cell engine operation as well as flight test operation on 100LL aviation grade and four blends of automotive grade fuel.

• Progress in Superconductivity and Cryogenics
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• v.24 no.2
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• pp.27-38
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• 2022

Urban air mobility (UAM) has recently attracted lots of attention as a solution to urban centralization and global warming. Electric vertical take-off and landing (eVTOL) is a concept that emerges as one of the promising and clean technologies for UAM. There are two difficult challenges for eVTOL aircraft to solve. One is how to improve the weight efficiency of aircraft, and the other is how to complete long-range missions for UAM's flight scenarios. To approach these challenges, we propose a consolidated concept design of battery-fuel cell hybrid tiltrotor aircraft with a liquid hydrogen (LH₂) fuel tank. The efficiency of a battery-fuel cell hybrid powertrain system on the designed eVTOL aircraft is compared to that of a battery-only powertrain system. This paper shows how much payload can increase and the flight scenario can be improved by hybridizing the battery and fuel cell and presenting a detailed concept of a cryogenic storage tank for LH₂.

• Advances in aircraft and spacecraft science
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• v.9 no.1
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• pp.17-37
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• 2022

This paper discusses an improved unmanned aerial vehicle, UAV, configuration characterized by telescopic booms to optimize the flight mechanics and fuel consumption of the aircraft at various loading/flight conditions.The starting point consists of a full-composite smaller UAV which was derived by a general aviation ultralight motorized aircraft ULM. The present design, named ToBoFlex, extends the two-booms configuration to a three tons aircraft. To adapt the design to needs relevant to different applications, new solutions were proposed in aerodynamic fields and materials and structural areas. Different structural solutions were reported. To optimize aircraft endurance, the innovative concept of Telescopic Tail Boom was considered along with two different tails architecture. A new structural configuration of the fuselage was proposed. Further consideration of hydrogen fuel cell electric propulsion is now being studied in collaboration between the Polytechnic of Turin and Prince Mohammad Bin Fahd University which could be the starting point of future investigations.

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.3
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• pp.58-63
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• 2009

The global restriction on pollutant emissions and the soaring of crude oil price are expected to result in the change of future transportation system. Hydrogen is considered to be the leading candidate as an alternative energy source before other new alternative energy sources emerge. Scientists anticipate that hydrogen fuel gas turbine engine and fuel cell will be the power plant of the aircraft in the near future. To realize the aircraft powered by fuel cell system in the future, the technologies such as fuel cell with higher energy density, compressed gas or liquid storage system of hydrogen fuel, and efficient and lightweight electric motor have to be developed first.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.9
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• pp.858-865
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• 2011

This paper describes the characteristics of hydrogen generation from solid-state $NaBH_4$ and fuel cell operation for fuel cell aircraft. The solid-state $NaBH_4$ was used for a high hydrogen storage density, and was reacted with hydrochloric acid to generate hydrogen. The hydrogen generation rate for the solid-state $NaBH_4$ reaction was measured at various conditions. As a result, the hydrogen generation rate was increased with the feed rate and concentration of hydrochloric acid, while not be affected by the reaction temperature. A fuel cell was connected with the solid-state $NaBH_4$ hydrogen generator. The stable power output was obtained at the gradual and sudden increases of electric loads.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.5
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• pp.405-411
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• 2012

Inside a rotorcraft fuel cell, pipes and components are located for fuel storage and fuel supply into the engine. Utility helicopters, operated in battle fields, fly at lower altitude compared to fixed-wing aircraft and hence are more likely to be exposed to gunfire. Since internal pressure of fluid increases when hit, the effect on LRU due to increase in pressure must taken into account when designing the aircraft for survivability. However, it is costly and time consuming to manufacture a fuel cell for gunfire test, and due to constraints from usage of live ammunition, related data gathered through numerical simulation is needed. In this study, numerical simulation on rotorcraft fuel cell exposed to gunfire was carried out using Autodyn to analyze bullet movement inside the fuel cell after hit, and internal pressure of fluid and equivalent stress on fuel cell assessed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.7
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• pp.590-600
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• 2012

In this research, generalized sizing methods were studied that can be applied to an aircraft which uses solar cell or fuel cell as energy sources. To consider multiple propulsion systems and energy resources, multiple power paths were modeled and the weight of consumable and non-consumable energy was reflected in the weight change calculation for each mission segments. In the constraint analysis, power to weight ratio was selected instead of thrust to weight ratio and used in the sizing process of balancing power and energy.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.544-547
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• 2011

This paper describes on hardware simulation of passive power control of propulsion system for electric propulsion aircraft of KARI. The propulsion system uses hybrid power system that is composed of solar cell, fuel cell and battery. The fuel cell is replaces by simulator due to its difficulty in handling while the other components are the same as that will be used on board. As the result, reliable power supply for propulsion is confirmed and each power source is well operated showing its characteristics.