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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

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

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

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

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

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

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

How Insects Affect the Cotton Plant and Means of Combating Them

Description: "The cotton plant is unusually attractive to insects and probably no other cultivated crop has as large a list of insect enemies. Among these are some of the most destructive pests in the history of agriculture. Many cotton pests come to the cotton from other crops or from weeds around the fields. Weeds should not be allowed to grow. Rotation of crops is of assistance in controlling cotton pests. Poisons seldom are needed, except in poisoned baits in the spring and against red spiders, grasshoppers, and 'worms' when they threaten the crop. Thorough fall plowing, winter cover crops, early spring preparation, and repeated cultivation during the season are important measures of insect control. The cotton plants should be turned under in the fall. This bulletin describes the work of many insects and gives suggestions for their control." -- p. 2. Among the insects discussed are ants, cutworms, may beetles, aphids, grassworms, grasshoppers, bollworms, wireworms, and crickets.
Date: 1917
Creator: Pierce, W. Dwight (William Dwight), 1881-1967
Partner: UNT Libraries Government Documents Department

The Rough-Headed Corn Stalk-Beetle in the Southern States and Its Control

Description: "Within recent years an increasing number of reports of serious damage to the corn crop by a robust black beetle have been received from most of the Southern States. A noteworthy outbreak occurred during the early summer of 1914 in the tidewater section of Virginia. As very little was known regarding the natural history of this pest, this bulletin has been designed to supply this information. By following the control measures recommended herein it is hoped that the ravages of this pest may be largely overcome in the future." -- p. 3
Date: 1917
Creator: Phillips, W. J. (William Jeter), 1879-1972
Partner: UNT Libraries Government Documents Department

Grasshoppers and Their Control

Description: "Grasshoppers in a single year have destroyed crops valued at over a hundred million dollars. The best way to prevent losses is the use of poisoned bait supplemented by tillage and seeding methods which restrict egg laying and imprison the young grasshoppers in the ground after they hatch. Bait is most effective while grasshoppers are still on their hatching grounds or massed along field margins. It should be put out when grasshoppers are doing their first feeding of the day. This usually occurs between 6 and 10 a.m. at temperatures of 70° to 80°F. Bait should not be spread unless grasshoppers are actively feeding. In mixing and distributing the poisoned bait care should be taken to prevent injury to persons and farm animals. Seeding grain only on plowed or summer-fallowed ground and plowing infested stubble before the eggs hatch greatly reduces the quantity of bait needed for control and decreases the liability of crop injury. Cooperation in the use of control methods by all the farmers in a community is necessary for best results." -- p. i
Date: 1939
Creator: Parker, J. R.
Partner: UNT Libraries Government Documents Department

Cutworms in the Garden.

Description: A guide to identifying cutworm interference and controlling cutworms in the garden. Provides information on obtaining and handling arsenic poison.
Date: March 1927
Creator: White, W. H. (William Henry), 1892-1951
Partner: UNT Libraries Government Documents Department