National Advisory Committee for Aeronautics (NACA) - 31 Matching Results

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A method for predicting the stability in roll of automatically controlled aircraft based on the experimental determination of the characteristics of an automatic pilot

Description: Report presenting a method for predicting the stability of automatically controlled aircraft by comparing the calculated frequency-response curves for the aircraft and experimentally determined frequency-response curves for the automatic pilot. The method is applicable only to stabilization in roll. It can be used to establish the specifications of performance required for the automatic control device for pilotless aircraft designed as missiles.
Date: January 17, 1947
Creator: Jones, Robert T. & Sternfield, Leonard
Partner: UNT Libraries Government Documents Department

Longitudinal stability and control characteristics of an airplane model having a 42.8 degree sweptback circular-arc wing with aspect ratio 4.00, taper ratio 0.50, and sweptback tail surfaces

Description: Report presenting testing of an airplane model with a 42.8 degree sweptback wing with an aspect ratio of 4.00, taper ratio of 0.50, and a 42.8 degree sweptback horizontal tail, and a 40.3 degree sweptback vertical tail to determine its low-speed longitudinal stability and control characteristics. Other variables investigated include the vertical-wing location, fuselage size, horizontal-tail location, and stall-control vanes on the wing.
Date: October 17, 1947
Creator: Weil, Joseph; Comisarow, Paul & Goodson, Kenneth W.
Partner: UNT Libraries Government Documents Department

The effect of rear chine strips on the take-off characteristics of a high-speed airplane fitted with NACA hydro-skis

Description: From Summary: "Results are presented from tank take-off tests of a dynamic model of a hypothetical high-speed airplane fitted with NACA hydro-skis and having the transverse curvature of the lower rear portion of the fuselage broken by small longitudinal chine strips. For the configuration tested, both trim and resistance were considerably reduced by the addition of the strips from the speed at which the ski emerged to the speed at which the rear of the fuselage came clear of the water. The results indicate that fuselage shape has a large effect on the take-off characteristics for a hydro-ski configuration in which the rear of the fuselage acts as a planing surface."
Date: March 17, 1949
Creator: Ramsen, John A.
Partner: UNT Libraries Government Documents Department

Control during starting of gas-turbine engines

Description: Report presenting an investigation of the variables pertinent to the control of gas temperatures of gas-turbine engines during starting conducted by obtaining time records of the variables involved during actual starting conditions. Poor control of gas temperatures during starting was found to be caused by an accumulation of fuel in the engine before ignition and excessive fuel-flow rates at the time of ignition.
Date: June 17, 1948
Creator: Koenig, Robert J. & Dandois, Marcel
Partner: UNT Libraries Government Documents Department

Investigation of shock diffusers at Mach number 1.85 2: projecting double-shock cones

Description: Report presenting an investigation in the 18- by 18-inch supersonic tunnel to determine the total-pressure recovery obtainable at Mach number 1.85 with a shock diffuser with projective cones designed to produce two oblique shocks ahead of the diffuser inlet. The variation of total-pressure recovery with tip projection was investigated for four cones with different included angles. A maximum total-pressure recovery of 94.5 percent was attained with the best configuration at an angle of 0 degrees.
Date: June 17, 1947
Creator: Moeckel, W. E.; Connors, J. F. & Schroeder, A. H.
Partner: UNT Libraries Government Documents Department

Lateral stability and control characteristics of an airplane model having 42.8 degree sweptback circular-arc wing with aspect ratio 4.00, taper ratio 0.50, and sweptback tail surfaces

Description: Report presenting testing in the 300 mph 7- by 10-foot tunnel of an airplane model with a 42.8 degree sweptback wing with an aspect ratio 4.00, taper ratio 0.50, a 42.8 degree sweptback horizontal tail, and a 40.3 degree sweptback vertical tail to determine the low-speed lateral stability and control characteristics. Some changes made to improve the aerodynamic characteristics included lowering the wing, incorporating a smaller-fineness-ratio fuselage, and increasing the vertical tail size. Results regarding various configurations, including the semihigh wing with large fuselage, low wing with large fuselage, low wing with small fuselage and small vertical tail, and low wing with small fuselage and large vertical tail are provided.
Date: October 17, 1947
Creator: Goodson, Kenneth W. & Comisarow, Paul
Partner: UNT Libraries Government Documents Department

A method for predicting the stability in roll of automatically controlled aircraft based on the experimental determination of the characteristics of an automatic pilot

Description: Report presenting a method for predicting the stability of automatically controlled aircraft by a comparison of calculated frequency-response curves for the aircraft and experimentally determined frequency-response curves for the automatic pilot. The method is expected to be useful to establish the specifications of the performance required of the automatic control device for pilotless aircraft designed as missiles.
Date: January 17, 1947
Creator: Jones, Robert T. & Sternfield, Leonard
Partner: UNT Libraries Government Documents Department

Preliminary Wind-Tunnel Tests of Triangular and Rectangular Wings in Steady Roll at Mach Numbers of 1.62 and 1.92

Description: Report presenting the damping-in-roll coefficients for a series of thin triangular plan-form wings and two rectangular wings in the 9-inch supersonic wind tunnel. The damping in roll of the rectangular wings was very close to what was predicted by linear theory, but the triangular wings gave results approximately 10 percent below that predicted when the wing leading edges were well ahead of or behind the Mach cone.
Date: February 17, 1949
Creator: Brown, Clinton E. & Heinke, Harry S., Jr.
Partner: UNT Libraries Government Documents Department

Use of source distributions for evaluating theoretical aerodynamics of thin finite wings at supersonic speeds

Description: From Summary: "A series of publications on the source-distribution methods for evaluating the aerodynamics of thin wings at supersonic speeds is summarized, extended, and unified. Included in the first part are the deviations of: (a) the linearized partial-differential equation for unsteady flow at a substantially constant Mach number. b) The source-distribution solution for the perturbation-velocity potential that satisfies the boundary conditions of tangential flow at the surface and in the plane of the wing; and (c) the integral equation for determining the strength and the location of sources to describe the interaction effects (as represented by upwash) of the bottom and top wing surfaces through the region between the finite wing boundary and the foremost Mach wave. The second part deals with steady-state thin-wing problems. The third part of the report approximates the integral equation for unsteady upwash and includes a solution of approximate equation. Expressions are then derived to evaluate the load distributions for time-dependent finite-wing motions."
Date: June 17, 1949
Creator: Evvard, John C.
Partner: UNT Libraries Government Documents Department

Free-Spinning-Tunnel Investigation of a 1/20-Scale Model of the McDonnell XF2H-1 Airplane

Description: A spin-recovery investigation has been conducted in the Langley 20-foot free-spinning tunnel on a 20-scale model modified to represent the McDonnell XF2H-1 airplane. The project included tests both with tip tanks installed and with the tanks removed. The results indicated that the recovery characteristics of the airplane would be satisfactory for all loadings by normal recovery technique (full reversal of the rudder, followed 1/2 turn later by movement of the elevator down). The rudder pedal and the elevator stick forces likely to be encountered in a spin should be within the capabilities of the pilot.
Date: June 17, 1949
Creator: Berman, Theodore
Partner: UNT Libraries Government Documents Department

Stability and Control Characteristics of a 1/10-Scale Model of the McDonnell XP-85 Airplane While Attached to the Trapeze

Description: At the request of the Air Materiel Command, Army Air Forces, an investigation of the low-speed, power-off, stability and control characteristics of the McDonnell XP-85 airplane has been conducted in the Langley free-flight tunnel. The results of the portion of the investigation consisting of tests of a 1/10-scale model to study the stability of the XP-85 when attached to the trapeze and during retraction into the B-36 bomb bay are presented herein. In the power-off condition the stability was satisfactory with all oscillations well damped and the nose-restraining collar could be placed in position without difficulty. In a simulated power-on condition the model had a constant-amplitude rolling and sidewise motion and when the collar was layered, a violent motion resulted if the collar struck the model but failed to hold it in the proper manner. Folding of the wings and retraction into the bomb bay offered no problem once the airplane was properly held by the collar. It is recommended that the power be cut immediately after hooking on and that a restricting mechanism be incorporated in the center of the trapeze to eliminate the sidewise motion. It also appears desirable to have the retracting procedure controlled by the XP-85 pilot or an observer in the mother ship to insure that the parasite is in proper position after hooking up before bringing the collar down.
Date: November 17, 1947
Creator: Johnson, Joseph L.
Partner: UNT Libraries Government Documents Department

Free-Spinning-Tunnel Tests of a 1/16-Scale Model of the Chance Vought XF5U-1 Airplane, TED No. NACA 2349

Description: Spin tests of a 1/16-scale model of the Chance Vought XF5U-1 airplane have been performed in the Langley 20-foot free-spinning tunnel. The effect of control position and movement upon the erect and inverted spin and recovery characteristics ae well as the effects of propellers, of stability flaps, and of various revisions to the design configuration have been determined for the normal fighter loading. The investigation also included spin recovery parachute, tumbling, and pilot-escape tests. For the original design configuration, with or without windmilling propellers, the recovery characteristics of the model were considered unsatisfactory. Increasing the maximum upward deflection of the ailavators from 45 deg to 65 deg resulted in greatly improved recovery characteristics. Dimensional revisions to the original airplane configuration, which satisfactorily improved the general spin and recovery characteristics of the model, consisted of: (1) a supplementary vertical tail 34 inches by 59 inches (full-scale) attached to a boom 80 inches aft of the trailing edge of the airplane in the plane of symmetry, (2) a large semispan undersurface spoiler placed along the airplane quarter-chord line and opened on the outboard side in a spin, or (3) two additional vertical tails 64 inches by 52 inches (full-scale) located at the tips of the ailavators. A satisfactory parachute arrangement for emergency spin recovery from demonstration spins was found to be an arrangement consisting of a 13.3-foot parachute attached by a 30-foot towline to the arresting gear mast on the airplane and opened simultaneously with an 8-foot parachute on the outboard end of the wing attached by a 3-foot towline. Tests indicated that pilot escape from a spin would be extremely hazardous unless the pilot is mechanically ejected from the cockpit. Model tumbling tests indicated that the airplane would not tumble.
Date: October 17, 1947
Creator: White, Richard P.
Partner: UNT Libraries Government Documents Department

Investigation of the Stability and Control Characteristics of a 1/20-Scale Model of the Consolidated Vultee XB-53 Airplane in the Langley Free-Flight Tunnel

Description: An investigation of the low-speed, power-off stability and control characteristics of a 1/20-scale model of the Consolidated Vultee XB-53 airplane has been conducted in the Langley free-flight tunnel. In the investigation it was found that with flaps neutral satisfactory flight behavior at low speeds was obtainable with an increase in height of the vertical tail and with the inboard slats opened. In the flap-down slat-open condition the longitudinal stability was satisfactory, but it was impossible to obtain satisfactory lateral-flight characteristics even with the increase in height of the vertical tail because of the negative effective dihedral, low directional stability, and large-adverse yawing moments of the ailerons.
Date: November 17, 1947
Creator: Bennett, Charles V.
Partner: UNT Libraries Government Documents Department

Free-Spinning-Tunnel Tests of a 1/24-Scale Model of the North American XP-86 Airplane

Description: A spin investigation has been conducted in the Langley 20-foot free-spinning tunnel on a 1/24-scale model of the North American XP-86 airplane. The effects of control settings and movements upon the erect and inverted spin and recovery characteristics of the model were determined for the design gross weight loading. The long-range loading was also investigated and the effects of extending slats and dive flaps were determined. In addition, the investigation included the determination of the size of spin-recovery parachute required for emergency recovery from demonstration spins, the rudder force required to move the rudder for recovery, and the best method for the pilot to escape if it should become necessary to do so during a spin. The results of the investigation indicated that the XP-86 airplane will probably recover satisfactorily from erect and inverted spins for all possible loadings. It was found that fully extending both slats would be beneficial but that extending the dive brakes would cause unsatisfactory recoveries. It was determined that a 10.0-foot-diameter tail parachute with a drag coefficient of 0.7 and with a towline 30.0 feet long attached below the jet exit or a 6.0-foot-diameter wingtip parachute opened on the outer wing tip with a towline 6.0 feet long would insure recoveries from any spins obtainable. The rudder-pedal force necessary to move the rudder for satisfactory recovery was found to be within the physical capabilities of the pilot.
Date: May 17, 1948
Creator: Berman, Theodore
Partner: UNT Libraries Government Documents Department

Performance of Compressor XJ-41-V Turbojet Engine 1 - Preliminary Investigation at Equivalent Compressor Speed of 8000 RPM

Description: From Summary: "At the request of the Air Material Command, Arm Air Forces, an investigation was conducted at the NACA Cleveland laboratory to determine the performance characteristics of the XJ-41-V turbojet-engine compressor. The complete compressor was mounted on a collecting chamber having an annular air-flow passage simulating the burner annulus of the engine and was driven by an electric motor. The compressor was extensively instrumented to determine the overall performance of the compressor, the characteristic performance of each of the compressor components, the state of the air stream in the simulated burner annulus, and the operation of the compressor bearings."
Date: January 17, 1947
Creator: Ginsburg, Ambrose & Creagh, John W. R.
Partner: UNT Libraries Government Documents Department

An Analytical Investigation of the Heat Losses from a U.S. Navy K-Type Airship

Description: From Summary: "The heat losses from the envelope surface of a U.S. Navy K-type airship are evaluated to determine if the use of heat is a feasible means of preventing ice and snow accumulations on lighter-than-air craft during flight and when moored uncovered. Consideration is given to heat losses in clear air (no liquid water present in the atmosphere) and in probable conditions of icing and snow. The results of the analysis indicate that the amount of heat required in flight to raise the surface temperature of the entire envelope to the extent considered adequate for ice protection, based on experience with tests of heavier-than-air craft, is very large."
Date: February 17, 1947
Creator: Hillendahl, Wesley H. & George, Ralph E.
Partner: UNT Libraries Government Documents Department

Hydrodynamic impact of a system with a single elastic mode I : theory and generalized solution with an application to an elastic airframe

Description: Solutions of impact of a rigid prismatic float connected by a massless spring to a rigid upper mass are presented. The solutions are based on hydrodynamic theory which has been experimentally confirmed for a rigid structure. Equations are given for defining the spring constant and the ratio of the sprung mass to the lower mass so that the two-mass system provides representation of the fundamental mode of an airplane wing. The forces calculated are more accurate than the forces which would be predicted for a rigid airframe since the effect of the fundamental mode on the hydrodynamic force is taken into account. In a comparison of the theoretical data with data for a severe flight-test landing impact, the effect of the fundamental mode on the hydrodynamic force is considered and response data are compared with experimental data.
Date: March 17, 1947
Creator: Mayo, Wilbur L.
Partner: UNT Libraries Government Documents Department

Tank Tests of 1/5.5-Scale Forward Dynamic Model of the Columbia XJL-1 Amphibian - Langley Tank Model 208, TED No. NACA 2336

Description: Tests of a powered dynamic model of the Columbia XJL-1 amphibian were made in Langley tank no.1 to determine the hydrodynamic stability and spray characteristics of the basic hull and to investigate the effects of modifications on these characteristics. Modifications to the forebody chime flare, the step, and the afterbody, and an increase in the angle of incidence of the wing were included in the test program. The seaworthiness and spray characteristics were studied from simulated taxi runs in smooth and rough water. The trim limits of stability, the range of stable positions of the enter of gravity for take-off, and the landing stability were determined in smooth water. The aerodynamic lift, pitching moment, and thrust were determined at speeds up to take-off speed.
Date: February 17, 1947
Creator: Havens, Robert F.
Partner: UNT Libraries Government Documents Department

NACA Investigation of a Jet-Propulsion System Applicable to Flight

Description: "Following a brief history of the NACA investigation of jet propulsion, a discussion is given of the general investigation and analysis leading to the construction of the jet-propulsion ground-test mock-up. The results of burning experiments and of test measurements designed to allow quantitative flight performance predictions of the system are presented and correlated with calculations. These calculations are then used to determine the performance of the system on the ground and in the air at various speeds and altitudes under various burning conditions. The application of the system to an experimental airplane is described and some performance predictions for this airplane are made" (p. 1).
Date: September 17, 1943
Creator: Ellis, Macon C., Jr. & Brown, Clinton E.
Partner: UNT Libraries Government Documents Department

Calibration Tests of a German Log Rodmeter

Description: A German log rodmeter of the pitot static type was calibrated in Langley tank no. 1 at speeds up to 34 knots and angles of yaw from 0 deg to plus or minus 10 3/4 degrees. The dynamic head approximated the theoretical head at 0 degrees yaw but decreased as the yaw was increased. The static head was negative and in general became more negative with increasing speed and yaw. Cavitation occurred at speeds above 31 knots at 0 deg yaw and 21 knots at 10 3/4 deg yaw.
Date: March 17, 1949
Creator: Mottard, Elmo J. & Stillman, Everette R.
Partner: UNT Libraries Government Documents Department