Disk Wing Research Articles

Dynamics of Main Rotor to Disk Wing Conversion

The accelerations that emerge in the disk wing during rotation have been found. The loading of wing elements have been determined when the blades are extended and retracted.

A mathematical model of transforming the vertical takeoff and landing aircraft with a disk wing at maneuvering (on a deck)

The motion of blades relative to the disk wing at the extension and retraction modes is defined. The general solution is obtained including the fuselage motion under the action of control or external disturbance.

Disk wing to main rotor conversion mechanics

A mathematical model of spatial motion of the disk wing blades converted to the main rotor is presented. The system linkage parameters are defined.

Generating Asian citrus Psyllid Diaphorina citri Kuwayama (Homoptera: Psyllidae) with twisting wings to prevent the spread of citrus greening disease

Huanglongbing (HLB) is seriously threatening and causing considerable economic losses to the citrus groves. Its Management depends critically on the control of the Asian citrus Psyllid (ACP), the vector of the cause of HLB, Candidatus Liberibacter asiaticus bacteria (CLas). Silencing genes by RNA interference (RNAi) is a promising technique to control pests. In this study, the abnormal disk wing (awd) has been selected from the available psyllid annotated genome. It has been known that awd gene encodes a nucleoside diphosphate kinase and is associated with wing development. This research focused on the effect of RNAi of awd gene on ACP nymph instars that acquired dsRNA. The Results provide evidence that using the dsRNA of awd gene has diminished the development and survival of ACP nymphs. Moreover, knockdown of awd gene expression was observed through malformation of adult wings. Also, the expression of awd was messured by quantitative PCR (qPCR). Furthermore, we are conducting experiments to investigate awd's possible contribution in temperature tolerance. We attempt to establish effective practical application to prevent the spread of HLB in friendly environmentally strategy.

The effect of gyroscopic couples on disk-wing aircraft stability

We present the results of studying the dynamic stability of an aircraft with a rotating disk wing (disk-wing aircraft), from which the helicopter-type blades are extended at takeoff and landing. The aircraft trajectory, when entering a descending airflow, is studied.

Disk wing as a solution of some “eternal” problems of main rotor

A possibility of using the main rotor in designing a vertical takeoff and landing aircraft with a disk wing is analyzed. We propose integrating the main rotor and a disk wing for solving some problems of main rotors.

Simulation of a spinstabilised sports disc

The spin-stabilised sports disc, more commonly known as the Frisbee, is used for a variety of recreation and sporting activities. Frisbees have unique flying characteristics compared to other sports projectiles because they depend on spin for stability during flight and, at typical launch speeds, aerodynamic lift is greater than or equal to the weight of the disc. In this paper, a six degree of freedom mathematical model of a spinning disc wing is developed and a simple analytical expression derived for the disc roll rate in straight and level flight. It is shown that dimensionless disc trajectories will be similar for similar values of a parameter based on the ratio of the disc static margin to the disc advance ratio. The mathematical model is implemented as a simulation in Matlab using steady model parameters obtained from wind tunnel tests and unsteady parameters from flight tests. Simulation results are shown to be in reasonable agreement with limited available experimental flight data. The effect of launch conditions has been investigated using a series of numerical experiments. It is found that flight path curvature in the horizontal plane increases with decreasing advance ratio, as expected. Pitch angles at launch for maximum range and maximum duration are approximately 10° and 20° respectively. Also, the locus of disc landing position as a function of launch roll angle has been shown to be an ‘S’ shaped curve, with the straightest flight occurring for an initial roll angle of-6°. Finally, the simulation has been extended to include the effects of hypothetical control inputs, enabling simulation of novel Frisbee manoeuvres.

Strain relaxation effect in microdisk lasers with compressively strained quantum wells

From lasing wavelengths observed for many samples of microdisk lasers with GaInAsP compressively strained quantum wells (CS-QWs), we estimate the gain peak redshifted by ∼10 meV. We explain this phenomenon as the strain relaxation in the CS-QWs at the disk wing exposed to the air. Band and rate equation analyses show that the built-in potential by strain relaxation accelerates the carrier diffusion toward the disk edge and reduces the threshold to 30%–60% of that without strain relaxation. This result indicates the advantage of CS-QWs not only for the microdisk laser but also for various microlasers with a membrane structure, e.g., photonic crystal slab lasers.

Ultrasmall and ultralow threshold GaInAsP-InP microdisk injection lasers: design, fabrication, lasing characteristics, and spontaneous emission factor

We have calculated lasing characteristics of current injection microdisk lasers of several microns in diameter, taking account of the scattering loss at center posts and the carrier diffusion effect. We found that the optimum width of the disk wing exposed to the air is 0.6-0.7 /spl mu/m and the minimum threshold current is nearly 10 /spl mu/A for the disk diameter of 2 /spl mu/m. The internal differential quantum efficiency can be 95% if the transparent carrier density is reduced to 7.5/spl times/10/sup 17/ cm/sup -3/ and the diffusion constant is increased to 8 cm/sup 2//s. In the experiment, we have obtained the room temperature continuous-wave operation of a GaInAsP-InP device of 3 /spl mu/m in diameter, for the first time, with a record low threshold of 150 /spl mu/A. This achievement was mainly owing to the reduction of the scattering loss at the disk edge, and hence the reduction of the threshold current density. The spontaneous emission factor was estimated to be 6/spl times/10/sup -3/. This value was much reduced by the large detuning of the lasing wavelength against the spontaneous emission peak. A larger value over 0.1, which is expected for such a small device, will be obtained by the wavelength tuning and the narrowing of the spontaneous emission spectrum.