7,801 research outputs found
Advances in understanding autogyro flight dynamics
A comprehensive flight dynamics study of the
autogyro is presented in this paper. A state of the art generic
simulation of the vehicle type was developed and validated
against flight data. This validation is presented in the paper
and it is shown that the model can be applied to the autogyro
with some confidence within well defined limitations
bounds. It is also shown that the general stability
characteristics of the autogyro can be considered as a mix of
helicopter and fixed wing aircraft modes of flight. Most
significantly the autogyro has a lightly damped, high
frequency phugoid mode. Further, it is demonstrated that
the only significant configurational effect is related to the
relative vertical position of the centre of gravity with respect
to the propeller thrustline, a centre of gravity which lies
above the thrustline being more desirable. Results from
preliminary handling qualities trials applying the techniques
of ADS33 to an autogyro are also presented. Results from
flight trials to investigate the teetering motion of the rotor
are described, and the influence of the research on air
accident investigation is also discussed
Technical writing practically unified through industry
General background details in the development of a university level technical writing program, based upon the writing tasks of the student's occupations, are summarized. Objectives and methods for unifying the courses of study with the needs of industry are discussed. Four academic course divisions, Industries Technologies, in which preparation and training are offered are: Animal, Horticulture, Agriculture, and Agricultural Business. Occupational competence is cited as the main goal for these programs in which technical writing is to be practically unified through industry. Course descriptions are also provided
Influence of coherent mesoscale structures on satellite-based Doppler lidar wind measurements
Efforts to develop display routines for overlaying gridded and nongridded data sets are discussed. The primary objective is to have the capability to review global patterns of winds and lidar samples; to zoom in on particular wind features or global areas; and to display contours of wind components and derived fields (e.g., divergence, vorticity, deformation, etc.). Current considerations in support of a polar orbiting shuttle lidar mission are discussed. Ground truth for a shuttle lidar experiment may be limited to fortuitous alignment of lidar wind profiles and scheduled rawinsonde profiles. Any improvement on this would require special rawinsonde launches and/or optimization of the shuttle orbit with global wind measurement networks
Range vegetation type mapping and above-ground green biomass estimations using multispectral imagery
The author has identified the following significant results. Range vegetation types have been successfully mapped on a portion of the 68,000 acre study site located west of Baggs, Wyoming, using ERTS-1 imagery. These types have been ascertained from field transects over a five year period. Comparable studies will be made with EREP imagery. Above-ground biomass estimation studies are being conducted utilizing double sampling techniques on two similar study sites. Information obtained will be correlated with percent relative reflectance measurements obtained on the ground which will be related to image brightness levels. This will provide an estimate of above-ground green biomass with multispectral imagery
Enhancing SPH using moving least-squares and radial basis functions
In this paper we consider two sources of enhancement for the meshfree
Lagrangian particle method smoothed particle hydrodynamics (SPH) by improving
the accuracy of the particle approximation. Namely, we will consider shape
functions constructed using: moving least-squares approximation (MLS); radial
basis functions (RBF). Using MLS approximation is appealing because polynomial
consistency of the particle approximation can be enforced. RBFs further appeal
as they allow one to dispense with the smoothing-length -- the parameter in the
SPH method which governs the number of particles within the support of the
shape function. Currently, only ad hoc methods for choosing the
smoothing-length exist. We ensure that any enhancement retains the conservative
and meshfree nature of SPH. In doing so, we derive a new set of
variationally-consistent hydrodynamic equations. Finally, we demonstrate the
performance of the new equations on the Sod shock tube problem.Comment: 10 pages, 3 figures, In Proc. A4A5, Chester UK, Jul. 18-22 200
Application LANDSAT imagery to geologic mapping in the ice-free valleys of Antarctica
The author has identified the following significant results. Studies in the Ice-Free Valleys are resulted in the compilation of a sizeable library of maps and publications. Rock reflectance measurements were taken during the Antarctic summer of 1973. Spectral reflectance of rocks (mostly mafic lava flows) in the McMurdo and Ice-Free Valleys areas were measured using a filter wheel photometer equipped to measure reflectances in the four Landsat bands. A series of samples were collected at regular intervals across a large differentiated, mafic sill near Lake Vida. Chemical analyses of the sample suggest that the tonal variations in this sill are controlled by changes in the iron content of the rock. False color images were prepared for a number of areas by the diazo method and with an optical multispectral biviewer. These images were useful in defining boundaries of sea ice, snow cover, and in the study of ablating glaciers, but were not very useful for rock discrimination
Studies on the Sensitivity of Gyroplane Dynamic Stability. Department of Aerospace Engineering internal report no. 9405
This Interim Report describes work conducted to address specifically two items of
concern highlighted at the Phase 1 Progress Meeting: the overestimate of rotorspeed obtained
with the engineering models; and the degree of instability predicted by the RASCAL model.
Both characteristics are not reflected in the existing limited flight test experience. Although this
additional work is limited in scope, it is felt that the results are significant enough to justify an
Interim Report
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