961 research outputs found
An analysis and simulation of landings utilizing stored-energy lift Final report, May 12 - Nov. 30, 1967
Computerized simulation of aircraft landing deceleration with stored energy lif
In-flight simulation study of decoupled longitudinal controls for the approach and landing of a STOL aircraft
In this decoupled concept, the natural interactions of the flight variables were suppressed, and the pilot operated a separate controller for each (fore-and-aft control column for flight path angle without speed or pitch attitude change, for example). The handling qualities of the decoupled airplane were judged to be very favorable. The precise path control led to small touchdown point dispersion along with consistently low sink rates. The decoupled control system provided significantly better flying qualities than did conventional SAS applied to the same basic airframe
Integrated lift/drag controller for aircraft
A system for altering the lift/drag characteristics of powered aircraft to provide a safe means of glide path control includes a control device integrated for coordination action with the aircraft throttle. Such lift/drag alteration devices as spoilers, dive brakes, and the like are actuated by manual operation of a single lever coupled with the throttle for integrating, blending or coordinating power control. Improper operation of the controller is inhibited by safety mechanisms
Integrated flight controller for light aircraft
Controller-throttle engages spoiler/dive brake system when throttle setting is below a fixed power setting and gradually increases effect of spoiler/dive brake as throttle is moved toward idle position; since action is automatically reversible, a sudden application of power abruptly terminates aerodynamic effects of spoiler/dive brake system
The landing flare: An analysis and flight-test investigation
Results are given of an extensive investigation of conventional landing flares in general aviation type airplanes. A wide range of parameters influencing flare behavior are simulated in experimental landings in a variable-stability Navion. The most important feature of the flare is found to be the airplane's deceleration in the flare. Various effects on this are correlated in terms of the average flare load factor. Piloting technique is extensively discussed. Design criteria are presented
An Isocurvature CDM Cosmogony. I. A Worked Example of Evolution Through Inflation
I present a specific worked example of evolution through inflation to the
initial conditions for an isocurvature CDM model for structure formation. The
model invokes three scalar fields, one that drives power law inflation, one
that survives to become the present-day CDM, and one that gives the CDM field a
mass that slowly decreases during inflation and so ``tilts'' the primeval mass
fluctuation spectrum of the CDM. The functional forms for the potentials and
the parameter values that lead to an observationally acceptable model for
structure formation do not seem to be out of line with current ideas about the
physics of the very early universe. I argue in an accompanying paper that the
model offers an acceptable fit to main observational constraints.Comment: 11 pages, 3 postscript figures, uses aas2pp4.st
Full-scale wind tunnel tests of a low-wing, single-engine, light plane with positive and negative propeller thrust and up and down flap deflection
Full scale wind tunnel tests of low wing, single engine, light aircraft with positive and negative propeller thrust and up and down flap deflection - graph
Gamma-ray emission from the solar halo and disk: a study with EGRET data
Context: The Sun has recently been predicted to be an extended source of
gamma-ray emission, produced by inverse-Compton (IC) scattering of cosmic-ray
(CR) electrons on the solar radiation field. The emission was predicted to be
extended and a confusing foreground for the diffuse extragalactic background
even at large angular distances from the Sun. The solar disk is also expected
to be a steady gamma-ray source. While these emissions are expected to be
readily detectable in the future by GLAST, the situation for available EGRET
data is more challenging. Aims: The theory of gamma-ray emission from IC
scattering on the solar radiation field by Galactic CR electrons is given in
detail. This is used as the basis for detection and model verification using
EGRET data. Methods: We present a detailed study of the solar emission using
the EGRET database, accounting for the effect of the emission from 3C 279, the
moon, and other sources, which interfere with the solar emission. The analysis
was performed for 2 energy ranges, above 300 MeV and for 100-300 MeV, as well
as for the combination to improve the detection statistics. The technique was
tested on the moon signal, with our results consistent with previous work.
Results: Analyzing the EGRET database, we find evidence of emission from the
solar disk and its halo. The observations are compared with our model for the
extended emission. The spectrum of the solar disk emission and the spectrum of
the extended emission have been obtained. The spectrum of the moon is also
given. Conclusions: The observed intensity distribution and the flux are
consistent with the predicted model of IC gamma-rays from the halo around the
Sun.Comment: Corrected typos, added acknowledgements. A&A in pres
Addendum to "Coherent radio pulses from GEANT generated electromagnetic showers in ice"
We reevaluate our published calculations of electromagnetic showers generated
by GEANT 3.21 and the radio frequency pulses they produce in ice. We are
prompted by a recent report showing that GEANT 3.21-modeled showers are
sensitive to internal settings in the electron tracking subroutine. We report
the shower and pulse characteristics obtained with different settings of GEANT
3.21 and with GEANT 4. The default setting of electron tracking in GEANT 3.21
we used in previous work speeds up the shower simulation at the cost of
information near the end of the tracks. We find that settings tracking electron
and positron to lower energy yield a more accurate calculation, a more intense
shower, and proportionately stronger radio pulses at low frequencies. At high
frequencies the relation between shower tracking algorithm and pulse spectrum
is more complex. We obtain radial distributions of shower particles and phase
distributions of pulses from 100 GeV showers that are consistent with our
published results.Comment: 4 pages, 3 figure
Search for Supersymmetric Dark Matter with Superfluid He3 (MACHe3)
MACHe3 (MAtrix of Cells of superfluid He3) is a project of a new detector for
direct Dark Matter search, using superfluid He3 as a sensitive medium. This
paper presents a phenomenological study done with the DarkSUSY code, in order
to investigate the discovery potential of this project of detector, as well as
its complementarity with existing and planned devices.Comment: 15 pages, 5 figures, submitted to Phys. Letters B, minor changes in
the tex
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