• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.277-278
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• 2002

Magnetron and Ion beam sputtering were used to texture the air-bearing surface of magnetic recording sliders. Flying height measurements and Laser-Doppler interferometry were used to compare the 'flyability' of textured and untextured sliders. Lubricant redistribution on the disk surface caused by slider/disk interactions was investigated using scanning ellipsometry (Surface Reflectance Analyzer (SRA)). The results show that slider surface texture causes only small changes in the flying height of sliders but reduces slider in-plane and out-of-plane vibrations. Textured sliders were found to cause less lubricant depletion on the disk surface than untextured sliders.

• Advances in aircraft and spacecraft science
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• v.1 no.3
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• pp.353-378
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• 2014

This paper deals with the early development of the Anuloid, an innovative disk-shaped VTOL aircraft. The Anuloid concept is based on the following three main features: the use of a ducted fan powered by a turboshaft for the lift production to take-off and fly; the Coanda effect that is developed through the circular internal duct and the bottom portion of the aircraft to provide further lift and control capabilities; the adoption of a system of ducted fixed and swiveling radial and circumferential vanes for the anti-torque mechanism and the flight control. The early studies have been focused on the CFD analysis of the Coanda effect and of the control vanes; the flyability analysis of the aircraft in terms of static performances and static and dynamic stability; the preliminary structural design of the aircraft. The results show that the Coanda effect is stable in most of the flight phases, vertical flight has satisfactory flyability qualities, whereas horizontal flight shows dynamic instability, requiring the development of an automatic control system.

• Advances in aircraft and spacecraft science
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• v.4 no.3
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• pp.237-267
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• 2017

Automatic trajectory re-planning is an integral part of unmanned aerial vehicle mission planning. In order to be able to perform this task, it is necessary to dispose of formulas or tables to assess the flyability of various typical flight segments. Notwithstanding their importance, there exist such data only for some particularly simple segments such as rectilinear and circular sub-trajectories. This article presents an analysis of a new, very efficient, way for an airplane to fly on an inclined circular trajectory. When it flies this way, the only thrust required is that which cancels the drag. It is shown that, then, much more inclined trajectories are possible than when they fly at constant speed. The corresponding equations of motion are solved exactly for the position, the speed, the load factor, the bank angle, the lift coefficient and the thrust and power required for the motion. The results obtained apply to both types of airplanes: those with internal combustion engines and propellers, and those with jet engines. Conditions on the trajectory parameters are derived, which guarantee its flyability according to the dynamical properties of a given airplane. An analytical procedure is described that ensures that all these conditions are satisfied, and which can serve for producing tables from which the trajectory flyability can be read. Sample calculations are shown for the Cessna 182, a Silver Fox like unmanned aerial vehicle, and an F-16 jet airplane.

• Advances in aircraft and spacecraft science
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• v.3 no.4
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• pp.399-425
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• 2016

The dynamical requirements are obtained for airplanes to travel on inclined circular trajectories. Formulas are provided for determining the load factor, the bank angle, the lift coefficient and the thrust or power required for the motion. The dynamical properties of the airplane are taken into account, for both, airplanes with internal combustion engines and propellers, and airplanes with jet engines. A procedure is presented for the construction of tables from which the flyability of trajectories at a given angle of inclination can be read, together with the corresponding minimum and maximum radii allowed. Sample calculations are shown for the Cessna 182, a Silver Fox like unmanned aerial vehicle, and a F-16 jet airplane.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.2
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• pp.9-15
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• 2014

'Visual segment surface' means a surface that extends from the missed approach point of non precision approaches (or the decision altitude location for approaches with vertical guidance and precision approaches) to the threshold to facilitate the identification of and protection from obstacles in this visual segment of the approach. Validation is the necessary final quality assurance step in the procedure design process, prior to publication. The purpose of validation is the verification of all obstacle and navigation data, and assessment of flyability of the procedure. This paper shows how to apply the protection for the visual segment of the approach procedure, and the results of the validation for visual segment surface conducted at an airport.

• Advances in aircraft and spacecraft science
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• v.4 no.4
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• pp.371-399
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• 2017

The motion of propeller driven airplanes, flying at constant speed on ascending or descending helical trajectories is analyzed. The dynamical abilities of the airplane are shown to result in restrictions on the ranges of the geometrical parameters of the helical path. The physical quantities taken into account are the variation of air density with altitude, the airplane mass change due to fuel consumption, its load factor, its lift coefficient, and the thrust its engine can produce. Formulas are provided for determining all the airplane dynamical parameters on the trajectory. A procedure is proposed for the construction of tables from which the flyability of trajectories at a given angle of inclination and radius can be read, with the corresponding minimum and maximum speeds allowed, the final altitude reached and the amount of fuel burned. Sample calculations are shown for the Cessna 182, a Silver Fox like unmanned aerial vehicle, and the C-130 Hercules.

• Advances in aircraft and spacecraft science
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• v.5 no.5
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• pp.551-579
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• 2018

This work is concerned with the motion of propeller driven airplanes, flying at constant velocity on ascending or descending rectilinear trajectories. Its purpose is to provide important features of rectilinear flights that are required for airplane trajectory planning but that cannot be found already published. It presents a method for calculating the amount of fuel used, the restrictions on the trajectory parameters, as inclination and speed, which result from the load factor, the lift coefficient, the positivity and upper boundedness of the power available. It presents a complete discussion of both ascending and descending flights, including gliding. Some original remarks are made about the parameters of gliding. It shows how to construct tables of parameters allowing to identify rapidly flyable trajectories. Sample calculations are shown for the Cessna 182 and a Silver Fox like unmanned aerial vehicle.

• Advances in aircraft and spacecraft science
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• v.10 no.5
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• pp.473-494
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• 2023

This article introduces a formalism for the analysis of airplane trajectories on which the motion is determined by specifying the power of the engines. It explains a procedure to solve the equations of motion to obtain the value of the relevant flight parameters. It then enumerates the constraints that the dynamical abilities of the airplane impose on the amount of fuel used, the speed, the load factor, the lift coefficient, the positivity and upper boundedness of the power available. Examples of analysis are provided to illustrate the method proposed, with rectilinear and circular trajectories. Two very different types of airplanes are used in the examples: a Silver Fox-like small UAV and a common Cessna 182 Skylane.

• Advances in aircraft and spacecraft science
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• v.4 no.4
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• pp.421-436
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• 2017

This paper presents the main outcomes of the preliminary development of the Anuloid, an innovative disk-shaped VTOL aircraft. The Anuloid has three main features: lift is provided by a ducted fan powered by a turboshaft; control capabilities and anti-torque are due to a system of fixed and movable surfaces that are placed in the circular internal duct and the bottom portion of the aircraft; the Coanda effect is exploited to enable the control capabilities of such surfaces. In this paper, results from flight mechanics are presented. The vertical flight dynamics were found to be desirable. In contrast, the horizontal flight dynamics of the aircraft shows both dynamic instability, and more importantly, insufficient pitch and roll control authority. Some recommendations and guidelines are then given aimed at the alleviation of such problems.

• Transactions of the Society of Information Storage Systems
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• v.6 no.1
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• pp.12-17
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• 2010

Thermally-assisted magnetic recording (TAMR) is a potentially promising approach to increase the storage density of hard disk drive (HDD). However, TAMR has some issues such as temperature effects, media problems, thermal deformation and light delivery. In this research, we focused on light delivery. One of the powerful methods to deliver the light from laser diode to recording medium is the use of an optical fiber and a specially designed prism. However, the TAMR with optical fiber may have some flyability problems induced by the mounted optical fiber and prism. Also, the TAMR suspension using an optical fiber has high vertical and pitch stiffness. Therefore, p-torque is greatly increased by the optical fiber. Also, flying height (FH) of the slider with TAMR suspension can be largely changed by p-torque. Therefore, in this paper, we focus on the pitch static attitude (PSA) tolerance and the FH by PSA of the TAMR suspension. The FH is investigated using various errors and the PSA tolerance for TAMR suspension is proposed.