3,069 Matching Results

Search Results

Advanced search parameters have been applied.

Effect of Current Design Trends on Airplane Spins and Recoveries

Description: Memorandum presenting a concept in aircraft design, which states that provision of a rolling moment in the direction of the turning rotation will be very effective, and may be necessary, for termination of any spin obtained. Current research indicates that wing sweep, use of heavy jet and rocket engines, in the fuselage, and long fuselage nose lengths are the primary causes of the changes in the nature of the spin and in the requirements for recovery.
Date: January 28, 1952
Creator: Neihouse, Anshal I.
Partner: UNT Libraries Government Documents Department

An analytical investigation of airplane spin-recovery motion by use of rotary-balance aerodynamic data

Description: From Introduction: "Many investigations have been made in the Langley 20-foot free-spinning tunnel in which the natures of airplane spins and recoveries have been determined experimentally with dynamically scaled-down models. The results of some of these investigations are presented in references 1 to 5."
Date: June 1954
Creator: Scher, Stanley H.
Partner: UNT Libraries Government Documents Department

Free-spinning-tunnel tests of a model of a canard airplane

Description: Report presenting a series of tests made in the 15-foot free-spinning tunnel to study the spin characteristics of a model of a hypothetical canard airplane, which was designed to be about the same size and have the same general aerodynamic characteristics as a Boeing B-247 airplane. The model spun normally and had excellent recovery characteristics.
Date: May 1943
Creator: Pepoon, Philip W.
Partner: UNT Libraries Government Documents Department

Analytical determination of the mechanism of an airplane spin recovery with different applied yawing moments by use of rotary-balance data

Description: From Introduction: "These aerodynamic data were used previously in an analytical investigation of a spin recovery by rudder reversal, the results of which have been published in reference 2. Because of certain discrepancies in the rotary-balance data similar to those discussed in reference 3, some modifications were made to the aerodynamic data used in calculating the results in reference 2 and also the results in this paper; these discrepancies and modifications are discussed in detail herein."
Date: December 1954
Creator: Burk, Sanger M., Jr.
Partner: UNT Libraries Government Documents Department

Mathematical treatise on the recovery from a flat spin

Description: In this mathematical investigation, made in collaboration with Dr. Wilhelm Schmidt, we interpret the temporary change (due to some disturbance) in the quantities which define the position of the airplane while in a flat spin. We further examine the effect of this change, of the means resorted to to produce the disturbance, and thus reveal the expedients available for recovering from a flat spin.
Date: November 1930
Creator: Fuchs, R.
Partner: UNT Libraries Government Documents Department

Free-spinning wind-tunnel tests of a low-wing monoplane with systematic changes in wings and tails V: effect of airplane relative density

Description: The reported tests are a continuation of an NACA investigation being made in the free-spinning wind tunnel to determine the effects of independent variations in load distribution, wing and tail arrangement, and control disposition on the spin characteristics of airplanes. The standard series of tests was repeated to determine the effect of airplane relative density. Tests were made at values of the relative-density parameter of 6.8, 8.4 (basic), and 12.0; and the results were analyzed. The tested variations in the relative-density parameter may be considered either as variations in the wing loading of an airplane spun at a given altitude, with the radii of gyration kept constant, or as a variation of the altitude at which the spin takes place for a given airplane. The lower values of the relative-density parameter correspond to the lower wing loadings or to the lower altitudes of the spin.
Date: January 11, 1940
Creator: Seidman, Oscar & Neihouse, A. I.
Partner: UNT Libraries Government Documents Department

Spin Tests of a Low-Lying Monoplane in Flight and in the Free-Spinning Wind Tunnel

Description: "Comparative full-scale and model spin tests were made with a low-lying monoplane in order to extend the available information as to the utility of the free-spinning wind tunnel as an aid in predicting full-scale spin characteristics. For a given control disposition the model indicated steeper spins than were actually obtained with the airplane, the difference being most pronounced for spins with elevators up. Recovery characteristics for the model, on the whole, agreed with those for the airplane, but a disagreement was noted for the case of recovery with elevators held full up" (p. 1).
Date: July 1940
Creator: Seidman, Oscar & McAvoy, William H.
Partner: UNT Libraries Government Documents Department

Influence of Tail Length Upon the Spin-Recovery Characteristics of a Trainer-Type-Airplane Model

Description: Note presenting the results of an investigation conducted to determine the effect of tail length on the spin and recovery characteristics of a model typical of a trainer-type airplane. The model used in the investigation was tested with two tail lengths, and the model with the shorter tail was tested with several ventral fins. Results indicated that the model with the longer tail length had the better recovery characteristics even when the short tail model had comparable or higher levels of tail-damping power factor.
Date: December 1948
Creator: Klinar, Walter J. & Snyder, Thomas L.
Partner: UNT Libraries Government Documents Department

Spin-Tunnel Tests of a 1/57.33-Scale Model of the Northrop XB-35 Airplane

Description: Report presenting testing of a model of the Northrop XB-35 airplane in the free-spinning tunnel in order to determine the spin characteristics and tumbling tendencies of the airplane. The spin tests indicated that for the normal loading condition, the model would not spin in the direction of the rudder for either the clean or the landing condition unless the wheel was set over with the rudder. Results regarding the spin tests in the clean condition, spin tests in the landing condition, tumbling tests, and consideration of control forces are provided.
Date: April 1944
Creator: Kamm, Robert W. & Pepoon, Philip W.
Partner: UNT Libraries Government Documents Department

Spin-tunnel investigation to determine the effect on spin recoveries of reducing the opening shock load of spin-recovery parachutes

Description: Report presenting an investigation in the 20-foot free-spinning tunnel to determine whether the effectiveness of a spin-recovery parachute would be influenced by a reduction, through the use of a shock absorber, or the opening shock load. The results indicated that a given spin-recovery parachute was effective with or without a rubber shock absorber installed in the parachute towline. Results regarding the effect of the shock absorber on spin-recovery characteristics and effect of porosity and towline length on shock load are provided.
Date: March 1950
Creator: Jones, Ira P., Jr. & Klinar, Walter J.
Partner: UNT Libraries Government Documents Department

Comparison of effects of ailerons and combinations of spoiler-slot-deflector arrangements on spin recovery of sweptback-wing model having mass distributed along the fuselage

Description: Report presenting an investigation in the free-spinning tunnel to determine the effect of lateral-control systems using various combinations of spoilers, slots, and deflectors as compared with ailerons on the spin-recovery characteristics of a model of a 35 degree swept-wing fighter loaded heavily along the fuselage. Testing indicated that the ailerons were favorable for recovery when they were deflected full with the spin. Results regarding the effect of ailerons and two spoiler-slot-deflector configurations are provided.
Date: November 24, 1954
Creator: Healy, Frederick M. & Klinar, Walter J.
Partner: UNT Libraries Government Documents Department

Comparison of model and full-scale spin recoveries obtained by use of rockets

Description: Report presenting an investigation of a 1/19-scale model of an unswept-wing trainer airplane in the 20-foot free-spinning tunnel to determine the rocket spin-recovery characteristics of the model for comparison with available full-scale-airplane results. A rocket was attached to each wing tip to fire in a direction to apply an antispin yawing moment about the Z body axis. Results regarding the full-scale spin recoveries by rockets, model spin recoveries by rudder reversal, model spin recoveries by rockets, and mass changes associated with installation of emergency device are provided.
Date: February 1954
Creator: Burk, Sanger M., Jr. & Healy, Frederick M.
Partner: UNT Libraries Government Documents Department

Comparison of Tail and Wing-Tip Spin-Recovery Parachutes as Determined by Tests in the Langley 20-Foot Free-Spinning Tunnel

Description: Report presenting tests of spin-recovery parachutes on six models of typical fighter and trainer airplanes conducted in the 20-foot free-spinning tunnel to obtain data for correlating model and full-scale results. Parachutes attached to the tail of the models, to the outer wing tip, to the inner wing tip, and to both wing tips were tested. Results regarding parachute construction, loading variations, effect of test altitude, and action of spin-recovery parachutes are provided.
Date: March 1946
Creator: Kamm, Robert W. & Malvestuto, Frank S., Jr.
Partner: UNT Libraries Government Documents Department


Description: The finite-temperature HFB cranking equations are solved for the two-level model. The pair gap, moment of inertia and internal energy are determined as functions of spin and temperature. Thermal excitations and rotations collaborate to destroy the pair correlations. Raising the temperature eliminates the backbending effect and improves the HFB approximation.
Date: July 1, 1980
Creator: Goodman, A.L.
Partner: UNT Libraries Government Documents Department

Solid-state NMR studies for DC 745: April--May 2000

Description: Powles et al. reported in 1961 that pdydimethyl siloxane melts exhibit a transverse decay of nuclear spin magnetization (T{sub 2}) that is nonexponential. This observation was interpreted in terms of the proton NMR signal from the melt having characteristics of a broad line. Since then, similar findings were obtained for other polymer melts too. Accordingly to Powles et al. this peculiar proton line shape was the result of an intramolecular direct dipole-dipole interaction between a pair of protons. They also suggested that this dipolar interaction was weak because the dipolar interaction was motionally averaged since the orientation-dependent local dipolar field is modulated by molecular dynamics. In sum, the consequences and the origins of nuclear spin correlations in viscous polymer melts were recognized almost 4 decades ago. In the 1970s, Cohen-Addad suggested that these weak proton dipolar interactions could be used to characterize polymer melts and networks. In this work, we have used some of these ideas to probe the effects of thermal treatments on the proton spin-spin relaxation times for DC745.
Date: December 1, 2000
Creator: Stephens, T. & Labouriau, A.
Partner: UNT Libraries Government Documents Department

Azimuthal and single spin asymmetry in deep-inelasticlepton-nucleon scattering

Description: The collinear expansion technique is generalized to thefactorization of unintegrated parton distributions and other higher twistparton correlations from the corresponding collinear hard parts thatinvolve multiple parton final state interaction. Such a generalizedfactorization provides a consistent approach to the calculation ofinclusive and semi-inclusive cross sections of deep-inelasticlepton-nucleon scattering. As an example, the azimuthal asymmetry iscalculated to the order of 1/Q in semi-inclusive deeply inelasticlepton-nucleon scattering with transversely polarized target. Anon-vanishing single-spin asymmetry in the "triggered inclusive process"is predicted to be 1/Q suppressed with a part of the coefficient relatedto a moment of the Sivers function.
Date: September 21, 2006
Creator: Liang, Zuo-tang & Wang, Xin-Nian
Partner: UNT Libraries Government Documents Department

Spin Spectrometer at the ALS and APS

Description: A spin-resolving photoelectron spectrometer, the"Spin Spectrometer," has been designed and built. It has been utilized at both the Advanced Light Source in Berkeley, CA, and the Advanced Photon Source in Argonne, IL. Technical details and an example of experimental results are presented here.
Date: April 20, 2007
Creator: Laboratory, Lawrence Livermore National; Missouri-Rolla, University of; Technologies, Boyd; Morton, Simon A; Morton, Simon A; Tobin, James G et al.
Partner: UNT Libraries Government Documents Department

Unvail the Mysterious of the Single Spin Asymmetry

Description: Single transverse-spin asymmetry in high energy hadronic reaction has been greatly investigated from both experiment and theory sides in the last few years. In this talk, I will summarize some recent theoretical developments, which, in my opinion, help to unvail the mysterious of the single spin asymmetry.
Date: January 5, 2010
Creator: Yuan, Feng
Partner: UNT Libraries Government Documents Department

Workshop Summary -- Accelerator Issues

Description: As we enter the high energy regime covered by RHIC and HERA, depolarization effects become strong, so that depolarization resonances begin to overlap. As a result, the ''good old days'' of the ZGS and AGS--when techniques for dealing with isolated resonances were sufficient--are now in the past, and a new generation of spin dynamics questions have to be addressed and new techniques have to be developed. Exciting results were presented at this workshop ranging from the recent rapid R&D advances on polarized H- sources to deeper understanding of the subtle spin dynamics involving Siberian snakes. This summary is an attempt to give some of the highlights.
Date: June 22, 1999
Creator: Chao, Alex
Partner: UNT Libraries Government Documents Department


Description: In the AGS spin resonances due to coupling may account for as much as a 50 percent loss in polarization at a reduced acceleration rate. The major source of coupling in the AGS is the solenoidal snake. In the past some preliminary work was done to understand this phenomena, and a method to overcome these resonances was attempted. However in the polarized proton run of 2002 we sought to study more thoroughly the response of these coupled spin resonances to the strength of the solenoidal snake, skew quadrupoles and vertical and horizontal betatron tune separation. In this paper we present our results and compare them with those predicted by a modified DEPOL program.
Date: June 2, 2002
Partner: UNT Libraries Government Documents Department