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Investigation by the transonic-bump method of a 35 degree sweptback semispan model equipped with a flap operated by a series of servovanes located ahead of and geared to the flap

Description: Report presenting an investigation in the 7- by 10-foot tunnel to determine the feasibility of using a serovane control at high-subsonic and low-transonic speeds. The control could presumedly be deflected with relatively low control forces compared to flap-type controls. Through the range tested, the servovane control produced increments of lift, pitching moment, and rolling moment int he correct direction over most of the angle-of-attack range tested.
Date: April 1956
Creator: Phillips, William H. & Thompson, Robert F.
Partner: UNT Libraries Government Documents Department

Simplified procedures for estimating flap-control loads at supersonic speeds

Description: Report presenting an investigation to determine the possibility of using simplified procedures for the estimation of control loads at supersonic speeds. The results indicated that relatively simple procedures are possible for the estimation of loadings on flap-type controls at supersonic speeds for cases when no flow separation occurs ahead of the hinge line.
Date: May 27, 1955
Creator: Czarnecki, K. R. & Lord, Douglas R.
Partner: UNT Libraries Government Documents Department

The effect on rudder control of slip stream body, and ground interference

Description: From Summary: "This investigation was undertaken to determine the relative effects of those factors which may interfere with the rudder control of an airplane, with especial reference to the process of landing. It shows that ground interference is negligible, but that the effects of a large rounded body and of the slip stream may combine to interfere seriously with rudder control at low flying speeds and when taxiing."
Date: September 1922
Creator: Hood, H. I. & Bacon, D. L.
Partner: UNT Libraries Government Documents Department

Investigations toward simplification of missile control systems

Description: Paper presenting three ideas regarding potential simplifications of missile-control systems in order to make them more reliable without sacrificing system performance. The three methods presented include an autorotating-vane spoiler, a bellows flap, and free controls. All are based on modified airplane control systems.
Date: November 12, 1953
Creator: Curfman, Howard J., Jr.; Strass, H. Kurt & Crane, Harold L.
Partner: UNT Libraries Government Documents Department

An optimum switching criterion for a third-order contactor acceleration control system

Description: A switching criterion for optimum performance of a third-order contractor acceleration control system having complex roots is presented. Analytical and analog-computer methods are utilized to determine this criterion. The resulting optimum transient responses are presented and compared with those of an equivalent linear system.
Date: August 1956
Creator: Passera, Anthony L. & Willoh, Ross G., Jr.
Partner: UNT Libraries Government Documents Department

Summary of lateral-control research

Description: "A summary has been made of the available information on lateral control. A discussion is given of the criterions used in lateral-control specifications, of the factors involved in obtaining satisfactory lateral control, and of the methods employed in making lateral-control investigations in flight and in wind tunnels. The available data on conventional flap-type ailerons having various types of aerodynamic balance are presented in a form convenient for use in design. The characteristics of spoiler devices and booster mechanisms are discussed" (p. 1).
Date: February 14, 1946
Creator: Toll, Thomas A.
Partner: UNT Libraries Government Documents Department

Optimum controllers for linear closed-loop systems

Description: Report presenting an analysis for optimum controllers of general, linear, time-invariant multiloop systems. General representations of controller characteristics, stable process characteristics, and error relations are used. General solutions are presented for four special cases.
Date: April 1953
Creator: Boksenbom, Aaron S.; Novik, David & Heppler, Herbert
Partner: UNT Libraries Government Documents Department

Characteristics of a Hydraulic Control Determined from Transient Data Obtained with a Turbojet Engine at Altitude

Description: Memorandum presenting characteristics of a hydraulic control as determined by analyzing transient data obtained with a turbojet engine operating in the altitude wind tunnel. The excellent overall performance of the speed control is attributed to the elimination of large lags in the control system, thereby permitting the use of relatively high loop gains while still maintaining satisfactory damping in transients. Some information regarding the frequency-response analysis of speed control, simulation of speed control, and acceleration control are provided.
Date: June 16, 1954
Creator: Vasu, George; Hinde, William L. & Craig, R. T.
Partner: UNT Libraries Government Documents Department

Comparison of Automatic Control Systems

Description: This report deals with a reciprocal comparison of an automatic pressure control, an automatic rpm control, an automatic temperature control, and an automatic directional control. It shows the difference between the "faultproof" regulator and the actual regulator which is subject to faults, and develops this difference as far as possible in a parallel manner with regard to the control systems under consideration. Such as analysis affords, particularly in its extension to the faults of the actual regulator, a deep insight into the mechanism of the regulator process.
Date: February 1941
Creator: Oppelt, W.
Partner: UNT Libraries Government Documents Department

Further Flight Tests on the Effectiveness of Handley Page Automatic Control Slots

Description: Investigation of damping in roll within range of maximum lift with the Albatross L 75, with and without Handley Page automatic control slots, revealed the following: Without control slots, any attempt to go beyond a certain angle of attack near c(sub a max) in glide and climb, is followed by sudden sideslip. The conduct of the airplane throughout the motions in roll, moreover, confirmed that all attempts to higher angles of attack are accompanied by sudden loss of damping in roll.
Date: September 1932
Creator: Pleines, Wilhelm
Partner: UNT Libraries Government Documents Department

Investigation of a nonlinear control system

Description: A discontinuous variation of coefficients of the differential equation describing the linear control system before nonlinear elements are added is studied in detail. The nonlinear feedback is applied to a second-order system. Simulation techniques are used to study performance of the nonlinear control system and to compare it with the linear system for a wide variety of inputs. A detailed quantitative study of the influence of relay delays and of a transport delay is presented.
Date: October 18, 1957
Creator: Flügge-Lotz, I.; Taylor, C. F. & Lindberg, H. E.
Partner: UNT Libraries Government Documents Department

Investigation of a nonlinear control system

Description: A discontinuous variation of coefficients of the differential equation describing the linear control system before nonlinear elements are added is studied in detail. The nonlinear feedback is applied to a second-order system. Simulation techniques are used to study performance of the nonlinear control system and to compare it with the linear system for a wide variety of inputs. A detailed quantitative study of the influence of relay delays and of a transport delay is presented.
Date: April 1957
Creator: Flügge-Lotz, I. & Taylor, C. F.
Partner: UNT Libraries Government Documents Department

Determination of control-surface characteristics from NACA plain-flap and tab data

Description: From Summary: "The data from previous NACA pressure-distribution investigations of plain flaps and tabs with sealed gaps have been analyzed and are presented in this paper in a form readily applicable to the problems of control-surface design. The experimentally determined variation of aerodynamic parameters with flap chord and tab chord are given in chart form and comparisons are made with the theory. With the aid of these charts and the theoretical relationships for a thin airfoil, the aerodynamic characteristics for control surfaces of any plan form with plain flaps and tabs with sealed gaps may be determined. A discussion of the basic equations of the thin-airfoil theory and the development of a number of additional equations that will be helpful in tail design are presented in the appendixes. The procedure for applying the data is described and a sample problem of horizontal tail design is included."
Date: 1941
Creator: Ames, Milton B., Jr. & Sears, Richard I.
Partner: UNT Libraries Government Documents Department

Investigations on the Stability, Oscillation, and Stress Conditions of Airplanes with Tab Control: First Partial Report. Derivation of the Equations of Motion and their General Solutions

Description: For the design and the construction of airplanes the control is of special significance, not only with regard to the flight mechhnical properties but also for the proportional arrangement of wing unit, fuselage, and tail unit. whereas these problems may be regarded as solved for direct control of airplane motions, that is, for immediate operation of the control surfaces, they are not clarified as to oscimtions, stability, and stress phenomena occurring in flight motions with Indirect control, ss realized for instance in tab control. Its modus operandi is based on the activation of a tab hinged to the trailing edge & the main control surface. Due to lift and drag variations, mcments originate about the axis of rotation of the main contnol surface which cause an up-or--down floating of the main control surface and thus a change in the direction of the airplane. Since this tab control means flying with free control surface , the treatment of this problem should provide the basis on which to judge stability, oscilhtton, and stress data.The present report is to represent a contribution toward the clarification of the problems arising and, to treat the longitudinal motion of an airplane.
Date: September 1949
Creator: Filzek, B.
Partner: UNT Libraries Government Documents Department

Theoretical Analysis and Bench Tests of a Control-Surface Booster Employing a Variable Displacement Hydraulic Pump

Description: From Summary: "The NACA is conducting a general investigation of servo-mechanisms for use in powering aircraft control surfaces. This paper presents a theoretical analysis and the results of bench tests of a control-booster system which employs a variable displacement hydraulic pump. The booster is intended for use in a flight investigation to determine the effects of various booster parameters on the handling qualities of airplanes. Such a flight investigation would aid in formulating specific requirements concerning the design of control boosters in general."
Date: January 28, 1947
Creator: Mathews, Charles W. & Kleckner, Harold F.
Partner: UNT Libraries Government Documents Department

Aerodynamic characteristics at transonic speeds of a 60 degree delta wing equipped with a constant-chord flap-type control with and without an unshielded horn balance: transonic-bump method

Description: Report presenting an investigation to determine the control hinge moments and effectiveness at transonic speeds of a delta wing equipped with a constant-chord flap-type control with and without an unshielded triangular horn balance in the 7- by 10-foot tunnel using the transonic-bump method. The data indicated that the horn balance control was consistently more effective in changing lift at all Mach numbers than was the plain control but there was no appreciable difference in pitching-moment effectiveness.
Date: September 16, 1952
Creator: Wiley, Harleth G. & Zontek, Leon
Partner: UNT Libraries Government Documents Department

Comparison of the control-force characteristics of two types of lateral-control system for large airplanes

Description: Report presenting an analysis of wind-tunnel data for two types of lateral-control system for large airplanes in order to determine the control-force characteristics and rolling effectiveness of each system. The two types of control systems explored are a spring-tab aileron and a combination spoiler and guide or pilot-aileron arrangement.
Date: September 1947
Creator: Deters, Owen J.
Partner: UNT Libraries Government Documents Department

Results of a rocket-model investigation of control-surface buzz and flutter on a 4-percent-thick unswept wing and on 6-, 9-, and 12-percent-thick swept wings at transonic speeds

Description: Memorandum presenting the results of an investigation of control-surface buzz and flutter on four rocket-powered models with a 4-percent-thick unswept wing and 6, 9 and 12-percent-thick 35 degree swept wings with free-floating and statistically mass-balanced control surfaces. The results showed that all of the control surfaces buzzed. The buzz is related to the presence of a shock wave near the control surface for subsonic speeds.
Date: November 20, 1953
Creator: Henning, Allen B.
Partner: UNT Libraries Government Documents Department

Investigation of an on-off inlet shock-position control on a 16-inch ram-jet engine

Description: Report presenting an investigation of a shock-positioning control on a 16-inch ramjet engine at a range of Mach numbers and angles of attack in a supersonic wind tunnel. The static-pressure rise across the inlet normal shock was utilized in setting the diffuser at its critical condition. Results regarding the sensing pressures, engine performance, control set engine operation, pressure data, operation of the control during Mach number change, and other applications of control are provided.
Date: November 29, 1954
Creator: Wilcox, Fred A.; Perchonok, Eugene & Hearth, Donald P.
Partner: UNT Libraries Government Documents Department

Rocket-model investigation to determine the hinge-moment and normal-force properties of a full-span, constant-chord, partially balanced trailing-edge control on a 60 degree clipped delta wing between Mach numbers of 0.50 and 1.26

Description: Report presenting a free-flight investigation of a rocket-powered research model to determine the hinge-moment and normal-force characteristics of a trailing-edge control on a delta wing between Mach numbers of 0.50 and 1.26. The hinge-line location of 40 percent control chord satisfactorily reduced the high hinge moments associated with plain flap-type controls. Results regarding hinge moments and normal force are provided.
Date: October 30, 1953
Creator: Martz, C. William & Goslee, John W.
Partner: UNT Libraries Government Documents Department

Transonic lateral and longitudinal aerodynamic characteristics of a lateral-control system employing rotatable airfoils mounted vertically at the wing tips of an unswept wing-fuselage-tail combination

Description: Report presenting the aerodynamic characteristics of a new type of lateral control through a range of Mach numbers. The control consisted of airfoils mounted vertically at the tips of the wing and could be rotated to induce rolling moments or lift on the wing surface. Results regarding lateral-control characteristics and lift-control characteristics are provided.
Date: January 7, 1958
Creator: Axelson, John A.
Partner: UNT Libraries Government Documents Department

Effects of a detached tab on the hinge-moment and effectiveness characteristics of an unswept trailing-edge control on a 60 degree delta wing at Mach numbers from 0.75 to 1.96

Description: Report presenting an experimental investigation in the blowdown tunnel to determine the balancing effects of a detached tab on a constant-chord trailing-edge control mounted on a 60 degree delta wing for a range of Mach numbers. Control hinge moments, rolling moments, and lift effectiveness of the semispan wing-body combination are provided.
Date: April 14, 1955
Creator: Morris, Odell A. & Westrick, Gertrude C.
Partner: UNT Libraries Government Documents Department

Flight investigation of the effect of control centering springs on the apparent spiral stability of a personal-owner airplane

Description: Report presents the results of a flight investigation conducted on a typical high-wing personal-owner airplane to determine the effect of control centering springs on apparent spiral stability. Apparent spiral stability is the term used to describe the spiraling tendencies of an airplane in uncontrolled flight as affected both by the true spiral stability of the perfectly trimmed airplane and by out-of-trim control settings. Centering springs were used in both the aileron and rudder control systems to provide both a positive centering action and a means of trimming the airplane.
Date: March 22, 1951
Creator: Campbell, John P.; Hunter, Paul A.; Hewes, Donald E. & Whitten, James B.
Partner: UNT Libraries Government Documents Department