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**Partner:**UNT Libraries Government Documents Department

**Collection:**Technical Report Archive and Image Library

- Theoretical investigation of longitudinal response characteristics of a swept-wing fighter airplane having a normal acceleration control system and a comparison with other types of systems
- No Description digital.library.unt.edu/ark:/67531/metadc57313/
- A Theoretical Investigation of Longitudinal Stability of Airplane with Free Controls Including Effect of Friction in Control System
- The relation between the elevator hinge-moment parameters and the control-forces for changes in forward speed and in maneuvers is shown for several values of static stability and elevator mass balance. digital.library.unt.edu/ark:/67531/metadc64954/
- A theoretical investigation of longitudinal stability of airplanes with free controls including effect of friction in control system
- No Description digital.library.unt.edu/ark:/67531/metadc60944/
- A Theoretical Investigation of Longitudinal Stability of Airplanes with Free Controls Including Effect of Friction in Control System
- The relation between the elevator hinge moment parameters and the control forces for changes in forward speed and in maneuvers is shown for several values of static stability and elevator mass balance. The stability of the short period oscillations is shown as a series of boundaries giving the limits of the stable regions in terms of the elevator hinge moment parameters. The effects of static stability, elevator moment of inertia, elevator mass unbalance, and airplane density are also considered. Dynamic instability is likely to occur if there is mass unbalance of the elevator control system combined with a small restoring tendency (high aerodynamic balance). This instability can be prevented by a rearrangement of the unbalancing weights which, however, involves an increase of the amount of weight necessary. It can also be prevented by the addition of viscous friction to the elevator control system provided the airplane center of gravity is not behind a certain critical position. For high values of the density parameter, which correspond to high altitudes of flight, the addition of moderate amounts of viscous friction may be destabilizing even when the airplane is statically stable. In this case, increasing the viscous friction makes the oscillation stable again. The condition in which viscous friction causes dynamic instability of a statically stable airplane is limited to a definite range of hinge moment parameters. It is shown that, when viscous friction causes increasing oscillations, solid friction will produce steady oscillations having an amplitude proportional to the amount of friction. digital.library.unt.edu/ark:/67531/metadc279589/
- Theoretical investigation of methods for computing drag from wake surveys at high subsonic speeds
- No Description digital.library.unt.edu/ark:/67531/metadc61268/
- Theoretical Investigation of Submerged Inlets at Low Speeds
- The general characteristics of the flow field in a submerged air inlet are investigated by theoretical, wind-tunnel, and visual-flow studies. Equations are developed for calculating the laminar and turbulent boundary-layer growth along the ramp floor for parallel, divergent, and convergent ramp walls, and a general equation is derived relating the boundary-layer pressure losses to the boundary-layer thickness. It is demonstrated that the growth of the boundary layer on the floor of the divergent-ramp inlet is retarded and that a vortex pair is generated in such an inlet. Functional relationships are established between the pressure losses in the vortices and the geometry of the inlet. A general discussion of the boundary layer and vortex formations is included, in which variations of the various losses and of the incremental external drag with mass-flow ratio are considered. Effects of compressibility are also discussed. digital.library.unt.edu/ark:/67531/metadc53583/
- Theoretical investigation of subsonic oscillatory blade-row aerodynamics
- No Description digital.library.unt.edu/ark:/67531/metadc56751/
- A theoretical investigation of the aerodynamics of wing-tail combinations performing time-dependent motions at supersonic speeds
- No Description digital.library.unt.edu/ark:/67531/metadc56788/
- Theoretical investigation of the attack phase of an automatic interceptor system at supersonic speeds with particular attention to aerodynamic and dynamic representation of the interceptor
- No Description digital.library.unt.edu/ark:/67531/metadc62896/
- A Theoretical Investigation of the Drag of Generalized Aircraft Configurations in Supersonic Flow
- It seems possible that, in supersonic flight, unconventional arrangements of wings and bodies may offer advantages in the form of drag reduction. It is the purpose of this report to consider the methods for determining the pressure drag for such unconventional configurations, and to consider a few of the possibilities for drag reduction in highly idealized aircraft. The idealized aircraft are defined by distributions of lift and volume in three-dimensional space, and Hayes' method of drag evaluation, which is well adapted to such problems, is the fundamental tool employed. Other methods of drag evaluation are considered also wherever they appear to offer amplifications. The basic singularities such as sources, dipoles, lifting elements and volume elements are discussed, and some of the useful inter-relations between these elements are presented. Hayes' method of drag evaluation is derived in detail starting with the general momentum theorem. In going from planar systems to spatial systems certain new problems arise. For example, interference between lift and thickness distributions generally appears, and such effects are used to explain the difference between the non-zero wave drag of Sears-Haack bodies and the zero wave drag of Ferrari's ring wing plus central body. Another new feature of the spatial systems is that optimum configurations generally are not unique, there being an infinite family of lift or thickness distributions producing the same minimum drag. However it is shown that all members of an optimum family produce the same flow field in a certain region external to the singularity distribution. Other results of the study indicate that certain spatial distributions may produce materially less wave drag and vortex drag than comparable planar systems. It is not at all certain that such advantages can be realized in practical aircraft designs, but further investigation seems to be warranted. digital.library.unt.edu/ark:/67531/metadc64032/
- A theoretical investigation of the dynamic lateral oscillatory stability of an airplane having a 60 degree triangular wing
- No Description digital.library.unt.edu/ark:/67531/metadc58196/
- Theoretical investigation of the dynamic lateral stability characteristics of Douglas design No. 39C, an early version of the X-3 research airplane
- Contains results of calculations made to determine the neutral oscillatory stability boundaries, period and time to damp of the oscillatory mode, and motions following disturbances. The calculations were made for Mach numbers of 0.75 and 2.3 at an attitude of 35,000 feet and for the landing condition at sea level. digital.library.unt.edu/ark:/67531/metadc57979/
- Theoretical investigation of the dynamic lateral stability characteristics of the Douglas X-3 research airplane : study 41-B
- No Description digital.library.unt.edu/ark:/67531/metadc58422/
- A Theoretical Investigation of the Dynamic Lateral Stability Characteristics of the MX-838 (XB-51) Airplane
- At the request of the Air Material Command, U. S. Air Force, a theoretical study has been made of the dynamic lateral stability characteristics of the MX-838 (XB-51) airplane. The calculations included the determination of the neutral-oscillatory-stability boundary (R = 0), the period and time to damp to one-half amplitude of the lateral oscillation, end the time to damp to one-half amplitude for the spiral mode. Factors varied in the investigation were lift coefficient, wing incidence, wing loading, and altitude. The results of the investigation showed that the lateral oscillation of the airplane is unstable below a lift coefficient of 1.2 with flaps . deflected 40deg but is stable over the entire speed range with flaps deflected 20deg or 0deg. The results showed that satisfactory oscillatory stability can probably be obtained for all lift coefficients with the proper variation of flap deflection and wing incidence with airspeed. Reducing the positive wing incidence improved the oscillatory stability characteristics. The airplane is spirally unstable for most conditions but the instability is mild and the Air Force requirements are easily met. digital.library.unt.edu/ark:/67531/metadc64779/
- A theoretical investigation of the effect of a target seeker sensitive to pitch attitude on the dynamic stability and response characteristics of a supersonic canard missile configuration
- No Description digital.library.unt.edu/ark:/67531/metadc59267/
- A theoretical investigation of the effect of auxiliary damping on the longitudinal response of a transonic bomber configuration in flight through continuous turbulence
- No Description digital.library.unt.edu/ark:/67531/metadc60775/
- A theoretical investigation of the effect of partial wing lift of hydrodynamic landing characteristics of V-bottom seaplanes in step impacts
- A theoretical investigation is made of the loads and motions in water-landing impacts of wide prismatic V-bottom seaplanes for constant partial wing-lift conditions where the resultant velocity of the seaplane is normal to the keel. An approximate method is given for applying the results of this investigation to the more general case of oblique impact. The increase in vertical hydrodynamic load factor due to wing-lift reduction is shown to be approximately 133 percent of the decrease in air load. digital.library.unt.edu/ark:/67531/metadc56543/
- :Theoretical investigation of the effect of the ailerons on the wing of an airplane
- The present work investigates, on the basis of Prandtl's wing theory, the form of the lift distribution when the ailerons are deflected in opposite directions. An ideal fluid and a wing with a rectangular form are assumed. The moments must not cause any rotation of the wing or any deviation from the rectilinear motion. digital.library.unt.edu/ark:/67531/metadc277502/
- A theoretical investigation of the effect of yawing moment due to rolling on lateral oscillatory stability
- No Description digital.library.unt.edu/ark:/67531/metadc54971/
- A theoretical investigation of the effect on the lateral oscillations of an airplane of an automatic control sensitive to yawing accelerations
- No Description digital.library.unt.edu/ark:/67531/metadc55308/
- Theoretical investigation of the effects of configuration changes on the center of pressure shift of a body-wing-tail combination due to angle of attack and Mach number at transonic and supersonic speeds
- No Description digital.library.unt.edu/ark:/67531/metadc61384/
- Theoretical investigation of the effects of configuration changes on the center-of-pressure shift of a body-wing-tail combination due to angle of attack and mach number at transonic speeds
- No Description digital.library.unt.edu/ark:/67531/metadc56462/
- Theoretical Investigation of the Effects of the Artificial-Feel System on the Maneuvering Characteristics of the F-89 Airplane
- The possibility of overshooting the anticipated normal acceleration as a result of the artificial-feel characteristics of the F-89C airplane at a condition of minimum static stability was investigated analytically by means of an electronic simulator. Several methods of improving the stick-force characteristics were studied. It is shown that, due to the lag in build-up of the portion of the stick force introduced by the bobweight, it would be possible for excessive overshoots of normal acceleration to occur in abrupt maneuvers with reasonable assumed control movements. The addition of a transient stick force proportional to pitching acceleration (which leads the normal acceleration) to prevent this occurring would not be practical due to the introduction of an oscillatory mode to the stick-position response. A device to introduce a viscous damping force would Improve the stick-force characteristics so that normal acceleration overshoots would not be likely, and the variation of the maximum stick force in rapid pulse-type maneuvers with duration of the maneuver then would have a favorable trend. digital.library.unt.edu/ark:/67531/metadc65491/
- Theoretical investigation of the effects upon lift of a gap between wing and body of a slender wing-body combination
- No Description digital.library.unt.edu/ark:/67531/metadc57491/
- A theoretical investigation of the heating-up period of injected fuel droplets vaporizing in air
- No Description digital.library.unt.edu/ark:/67531/metadc57102/
- A theoretical investigation of the influence of autopilot natural frequency upon the dynamic performance characteristics of a supersonic canard missile configuration with a pitch-attitude control system
- No Description digital.library.unt.edu/ark:/67531/metadc58918/
- A theoretical investigation of the influence of auxiliary damping in pitch on the dynamic characteristics of a proportionally controlled supersonic canard missile configuration
- No Description digital.library.unt.edu/ark:/67531/metadc58558/
- A theoretical investigation of the lateral oscillations of an airplane with free rudder with special reference to the effect of friction
- Charts showing the variation in dynamic stability with the rudder hinge-moment characteristics are presented. A stabilizing rudder floating tendency combined with a high degree of aerodynamic balance is shown to lead to oscillations of increasing amplitude. This dynamic instability is increased by viscous-friction in the rudder control system. The presence of solid friction in the rudder control system will cause steady oscillations of constant amplitude if the floating angle of the rudder per unit angle of sideslip is stabilizing and greater than a certain critical value that depends on other airplane parameters, such as vertical-tail area and airplane moment of inertia about the vertical axis. The amplitude of the steady oscillation is proportional to the amount of friction and is generally quite small but increases as the condition of dynamic instability is approached. An approximate method of calculating the amplitudes of the steady oscillation is explained and is illustrated by a numerical example. A more accurate step-by-step calculation of the motion is also made and it is shown that the agreement with the approximate method is good. digital.library.unt.edu/ark:/67531/metadc60027/
- A theoretical investigation of the lateral oscillations of an airplane with free rudder with special reference to the effect of friction
- No Description digital.library.unt.edu/ark:/67531/metadc279582/
- Theoretical investigation of the longitudinal response characteristics of a swept-wing fighter airplane having a pitch-attitude control system
- No Description digital.library.unt.edu/ark:/67531/metadc56890/
- Theoretical investigation of the performance of proportional navigation guidance systems : effect of method of positioning the radar antenna on the speed of response
- No Description digital.library.unt.edu/ark:/67531/metadc59356/
- Theoretical Investigation of the Performance of Proportional Navigation Guidance Systems-effect of Method of Positioning the Radar Antenna on the Speed of Response
- Proportional navigation guidance systems - radar antenna positioning effects on speed of response. digital.library.unt.edu/ark:/67531/metadc52867/
- Theoretical investigation of the performance of proportional navigation guidance systems : effect of missile configuration on the speed of response
- No Description digital.library.unt.edu/ark:/67531/metadc64700/
- A Theoretical Investigation of the Rolling Oscillations of an Airplane with Ailerons Free
- An analysis is made of the stability of an airplane with ailerons free, with particular attention to the motions when the ailerons have a tendency to float against the wind. The present analysis supersedes the aileron investigation contained in NACA Report No. 709. The equations of motion are first written to include yawing and sideslipping, and it is demonstrated that the principal effects of freeing the ailerons can be determined without regard to these motions. If the ailerons tend to float against the wind and have a high degree of aerodynamic balance, rolling oscillations, in addition to the normal lateral oscillations, are likely to occur. On the basis of the equations including only the rolling motion and the aileron deflection, formulas are derived for the stability and damping of the rolling oscillations in terms of the hinge moment derivatives and other characteristics of the ailerons and airplane. Charts are also presented showing the oscillatory regions and stability boundaries for a fictitious airplane of conventional proportions. The effects of friction in the control system are investigated and discussed. If the ailerons tend to trail with the wind, the condition for stable variation of stick force with aileron deflection is found to determine the amount of aerodynamic balance that may be used. If the ailerons tend to float against the wind, the period and damping of the rolling oscillations are found to be satisfactory (in a mass-balanced system) so long as the restoring moment is not completely balanced out. Unbalanced mass behind the hinge, however, has an unfavorable effect on the damping of the oscillations and so shifts the boundary that close aerodynamic balance may not be attainable. digital.library.unt.edu/ark:/67531/metadc63706/
- A theoretical investigation of the rolling oscillations of an airplane with ailerons free
- No Description digital.library.unt.edu/ark:/67531/metadc60943/
- A theoretical investigation of the rolling oscillations of an airplane with ailerons free
- An analysis is made of the stability of an airplane with ailerons free, with particular attention to the motions when the ailerons have a tendency to float against the wind. The present analysis supersedes the aileron investigation contained in NACA Technical Report no. 709. The equations of motion are first written to include yawing and sideslipping, and it is demonstrated that the principal effects of freeing the ailerons can be determined without regard to these motions. If the ailerons tend to float against the wind and have a high degree of aerodynamic balance, rolling oscillations, in addition to the normal lateral oscillations, are likely to occur. On the basis of the equations including only the rolling motion and the aileron deflection, formulas derived for the stability and damping of the rolling oscillations in terms of the hinge-moment derivatives are also presented showing the oscillatory regions and stability boundaries for a fictitious airplane of conventional proportion. The effects of friction in the control system are investigated and discussed. digital.library.unt.edu/ark:/67531/metadc60059/
- A theoretical investigation of the short-period dynamic longitudinal stability of airplane configurations having elastic wings of 0 degree to 60 degrees sweepback
- No Description digital.library.unt.edu/ark:/67531/metadc57159/
- Theoretical investigation of the stability at negative static margins of a supersonic missile with an autopilot sensitive to pitch angle and pitching velocity
- No Description digital.library.unt.edu/ark:/67531/metadc59176/
- Theoretical investigation of the supersonic lift and drag of thin, sweptback wings with increased sweep near the root
- No Description digital.library.unt.edu/ark:/67531/metadc57263/
- Theoretical investigation of thrust augmentation of turbojet engines by tail-pipe burning
- No Description digital.library.unt.edu/ark:/67531/metadc58105/
- Theoretical investigation of velocity diagrams of a single-stage turbine for a turbojet engine at maximum thrust per square foot turbine frontal area
- No Description digital.library.unt.edu/ark:/67531/metadc56180/
- Theoretical Investigations on the Efficiency and the Conditions for the Realization of Jet Engines
- Contents: Preliminary notes on the efficiency of propulsion systems; Part I: Propulsion systems with direct axial reaction rockets and rockets with thrust augmentation; Part II: Helicoidal reaction propulsion systems; Appendix I: Steady flow of viscous gases; Appendix II: On the theory of viscous fluids in nozzles; and Appendix III: On the thrusts augmenters, and particularly of gas augmenters. digital.library.unt.edu/ark:/67531/metadc64965/
- The theoretical lateral motions of an automatically controlled airplane subjected to a yawing moment disturbance
- No Description digital.library.unt.edu/ark:/67531/metadc54838/
- A theoretical lateral-stability analysis of XC-120 airplane
- No Description digital.library.unt.edu/ark:/67531/metadc57951/
- Theoretical lift and damping in roll at supersonic speeds of thin sweptback tapered wings with streamwise tips, subsonic leading edges, and supersonic trailing edges
- On the basis of linearized supersonic-flow theory, generalized equations were derived and calculations made for the lift and damping in roll of a limited series of thin sweptback tapered wings. Results are applicable to wings with streamwise tips and for a range of supersonic speeds for which the wing is wholly contained between the Mach cones springing from the wing apex and from the trailing edge of the root section. A further limitation is that the tip Mach lines may not intersect on the wing. For the portion of the wing external to the Mach cones springing from the leading edge of the wing tips, the pressure distributions for lift and roll previously obtained for the triangular wing are valid. For the portion of the wing contained within the wing-tip Mach cones a satisfactory approximation to the exact pressure distribution was obtained by application of a point-source-distribution method developed in NACA-TN-1382. A series of design curves are presented which permit rapid estimation of the lift-curve slope and damping-in-roll derivative for given values of aspect ratio, taper ratio, Mach number, and leading-edge sweep. (author). digital.library.unt.edu/ark:/67531/metadc65671/
- Theoretical lift and damping in roll of thin sweptback tapered wings with raked-in and cross-stream wing tips at supersonic speeds.subsonic leading edges
- No Description digital.library.unt.edu/ark:/67531/metadc55397/
- Theoretical lift and damping in roll of thin wings with arbitrary sweep and taper at supersonic speeds : supersonic leading and trailing edges
- No Description digital.library.unt.edu/ark:/67531/metadc55560/
- Theoretical lift and drag of thin triangular wings at supersonic speeds
- A method is derived for calculating the lift and the drag due to lift of point-forward triangular wings and a restricted series of sweptback wings at supersonic speeds. The elementary or "supersonic sources" solution of the linearized equation of motion is used to find the potential function of a line of doublets. The flow about the triangular flat plate is then obtained by a surface distribution of these doublet lines. The lift-curve slope of triangular wings is found to be a function of the ratio of the tangent of the apex angle to the tangent of the Mach angle. As the apex angle approaches and becomes greater than the Mach angle, the lift coefficient of the triangular wing becomes equal to that of a two-dimensional supersonic airfoil at the same Mach number. The drag coefficient due to lift of triangular wings with leading edges well behind the Mach cone is shown to be close to that of elliptically loaded wings of the same aspect ratio in subsonic flight. The resultant force on wings with leading edges outside the Mach cone, however, is shown to act normal to the surfaces and thus an induced drag equal to the lift times the angle of attack is obtained. digital.library.unt.edu/ark:/67531/metadc65466/
- Theoretical lift and drag of thin triangular wings at supersonic speeds
- No Description digital.library.unt.edu/ark:/67531/metadc55375/
- Theoretical lift distribution and upwash velocities for thin wings at supersonic speeds
- No Description digital.library.unt.edu/ark:/67531/metadc54356/