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Effect of distributed granular-type roughness on boundary-layer transition at supersonic speeds with and without surface cooling

Description: Report presenting an investigation to determine the effect of a distributed granular-type roughness on boundary-layer transition at several temperatures. The roughness was not found to introduce any disturbances of significant magnitude to influence transition. Surface cooling did not increase the value of the critical roughness Reynolds number for a distributed granular-type roughness either.
Date: March 10, 1958
Creator: Braslow, Albert L.
Partner: UNT Libraries Government Documents Department

Investigation of effects of various camouflage paints and painting procedures on the drag characteristics of an NACA 65(sub 421)-420, a = 1.0 airfoil section

Description: Report presenting an investigation of the effects of various camouflage paints and painting procedures on the drag characteristics of a low-drag airfoil in the two-dimensional low-turbulence pressure tunnel. While applying paint has generally been found to decrease smoothness and increase drag, the care taken in preparation and application of the paint seems to be the dominant influence on the drag. Testing occurred with several different types of paints and several different painting methods.
Date: July 1944
Creator: Braslow, Albert L.
Partner: UNT Libraries Government Documents Department

Investigation of surface irregularities on an NACA 63(420)-416, a=1.0 airfoil section for the Glenn L. Martin Company design 195

Description: Report presenting the results of an investigation made in the two-dimensional low-turbulence pressure tunnel of surface irregularities on a low-drag airfoil section. The primary objective was to determine the effects of riveted and piano-hinge-type skin joints and of an aileron slot of the drag characteristics. Any type of surface irregularities at the front spar were found to cause substantial increase in drag.
Date: October 1943
Creator: Braslow, Albert L.
Partner: UNT Libraries Government Documents Department

Two-dimensional wind-tunnel investigation of sealed 0.22-airfoil-chord internally balanced ailerons of different contour on an NACA 65(112)- 213 airfoil

Description: Report presenting a two-dimensional wind-tunnel investigation made of two interchangeable sealed 0.22-airfoil-chord internally balanced ailerons on an NACA 65(sub 112)-213 airfoil. One aileron tested was of true airfoil contour and the other was modified by partly eliminating the cusp near the trialing edge. Results regarding aileron effectiveness, aileron hinge moments, lift, drag, and airfoil pressure distribution and critical Mach number are provided.
Date: July 1946
Creator: Braslow, Albert L.
Partner: UNT Libraries Government Documents Department

Wind-tunnel investigation of aileron effectiveness of 0.20-airfoil-chord plain ailerons of true airfoil contour on NACA 65(sub 2)-415, 65(sub 3)-418 and 65(sub 4)-421 airfoil sections

Description: Report presenting an investigation in the two-dimensional low-turbulence pressure tunnel to determine the aileron effectiveness of 0.20-airfoil-chord plain ailerons of true airfoil contour on three different airfoil sections. The aileron effectiveness parameter decreased very slightly with an increase in airfoil thickness. Results regarding the plain-airfoil section characteristics, aileron effectiveness, lift characteristics, and effects of airfoil thickness are provided.
Date: August 1944
Creator: Braslow, Albert L.
Partner: UNT Libraries Government Documents Department

Two dimensional wind-tunnel investigation of low drag vertical-tail,horizontal-tail, and wing sections equipped with sealed internally balanced control surfaces

Description: Report presenting a two-dimensional wind-tunnel investigation of three low-drag airfoil sections equipped with sealed internally balanced control surfaces designed for use as vertical-tail, horizontal-tail, and wing sections. Testing included determination of control-surface effectiveness and hinge moments and airfoil section drag characteristics. Results regarding vertical-tail section, horizontal-tail section, wing section, and effect of sudden movement of transition on airplane control-surface characteristics are provided.
Date: April 1946
Creator: Braslow, Albert L.
Partner: UNT Libraries Government Documents Department

Two-dimensional wind-tunnel investigation of a 10.7-percent-thick symmetrical tail section with a 0.40 airfoil-chord control surface and a 0.20 control-surface-chord tab

Description: Report presenting an investigation of a 10.7-percent-thick symmetrical tail section equipped with a flat-side airfoil-chord flap with a flap-chord overhang and a plain flap-chord tab. Airfoil lift, drag, pitching-moment, and flap and tab hinge-moment characteristics were determined at various flap and tab deflections.
Date: June 1947
Creator: Braslow, Albert L.
Partner: UNT Libraries Government Documents Department

Investigation of Effects of Various Camouflage Paints and Painting Procedures on the Drag Characteristics of an NACA 65(Sub 421)-420, a = 1.0 Airfoil Section

Description: Bulletin presenting an investigation of the effects of various camouflage paints and painting procedures on the drag characteristics of a 60-inch-chord low-drag airfoil in the NACA two-dimensional low-turbulence pressure tunnel.
Date: July 1944
Creator: Braslow, Albert L.
Partner: UNT Libraries Government Documents Department

Further experimental studies of area suction for the control of the laminar boundary layer on a porous bronze NACA 64A010 airfoil

Description: Report presenting a low-turbulence wind-tunnel investigation of an NACA 64A010 airfoil with a porous surface to determine the reduction in section total-drag coefficient that can be obtained at large Reynolds numbers by using area suction. While previous testing has been reported on, the focus of this paper is primarily the results of additional tests of the same airfoil model equipped with a porous skin of lower porosity.
Date: May 1950
Creator: Braslow, Albert L. & Visconti, Fioravante
Partner: UNT Libraries Government Documents Department

Two-dimensional wind-tunnel investigation of two NACA 7-series type airfoils equipped with a slot-lip aileron, trailing-edge frise aileron, and a double slotted flap

Description: Report presenting a wind-tunnel investigation of two NACA 7-series type airfoils, one with 17.7-percent chord thickness and one with 15.4-percent chord thickness, each quipped with a 30-percent-airfoil-chord double slotted flap, a slot-lip aileron, and a trailing-edge Frise aileron with two amounts of overhang balance. Measurements of airfoil lift and drag, Frise aileron hinge moment, and slot-lip aileron hinge moment were obtained through a large range of deflection of flap, Frise aileron, and slot-lip aileron and section angle of attack. Satisfactory lateral control can be obtained by using this combination of airfoils, flaps, and ailerons.
Date: March 28, 1949
Creator: Braslow, Albert L. & Visconti, Fioravante
Partner: UNT Libraries Government Documents Department

Comparison of the Drag of a Fin-Stabilized Body of Revolution and of a Complete Airplane Configuration as Obtained at Transonic Speeds in a Slotted Wind Tunnel and in Free Flight

Description: From Summary: "A comparison of the zero-lift drag coefficients at Mach numbers from 0.81 to 1.41 of a fin-stabilized parabolic body of revolution as measured in the Langley transonic blowdown tunnel has been made with measurements obtained in free-flight on a larger but geometrically similar model. The absolute values of drag coefficient obtained in the slotted wind tunnel were equivalent to the free-flight drag-coefficient values up to a Mach number of 1.4 when adjustments were made for the effect on viscous drag of differences in Reynolds number between the two test conditions. Excellent agreement was obtained between the two tests for the pressure-drag variation with Mach number, regardless of whether the scale effect on skin friction was considered."
Date: August 1955
Creator: Howell, Robert R. & Braslow, Albert L.
Partner: UNT Libraries Government Documents Department

Ordinates and theoretical pressure-distribution data for NACA 6- and 6A-series airfoil sections with thicknesses from 2 to 21 and from 2 to 15 percent chord, respectively

Description: Basic thickness forms for six different airfoil sections are tabulated for four different thicknesses of chord. Theoretical values of pressure and velocity ratios required to obtain theoretical airfoil pressure distributions are also provided.
Date: September 1958
Creator: Patterson, Elizabeth W. & Braslow, Albert L.
Partner: UNT Libraries Government Documents Department

Simplified method for determination of critical height of distributed roughness particles for boundary-layer transition at Mach numbers from 0 to 5

Description: Report presenting a simplified method that has been devised for the determination of the critical height of three-dimensional roughness particles required to promote premature transition of a laminar boundary layer on models of airplanes or airplane components. Results regarding the calculation of critical roughness height, minimization of roughness drag, limitations, and simplifying considerations are provided.
Date: September 1958
Creator: Braslow, Albert L. & Knox, Eugene C.
Partner: UNT Libraries Government Documents Department

Experimental study of the effects of scale on the absolute values of zero-lift drag of aircraft configurations at transonic speeds

Description: Report presenting an investigation at a range of Mach numbers from 0.7 to 1.4 to determine the effect of scale on the zero-lift drag of a fin-stabilized body of revolution and a fighter-type airplane configuration. Results obtained at low values of Reynolds number were compared with larger scale data obtained on geometrically similar models in free flight. Results regarding fin-stabilized body and airplane model are provided.
Date: February 8, 1957
Creator: Howell, Robert R. & Braslow, Albert L.
Partner: UNT Libraries Government Documents Department

Experimental study of the effects of finite surface disturbances and angle of attack on the laminar boundary layer of an NACA 64A010 airfoil with area suction

Description: From Summary: "A Langley low-turbulence wind-tunnel investigation of a porous NACA 64A010 airfoil section has been made to determine the effectiveness of area suction in maintaining full-chord laminar flow behind finite disturbances and at angles of attacks other than 0 degrees. Aero suction resulted in only a small increase in the size of a finite disturbance required to cause premature boundary-layer transition as compared with that for the airfoil without suction. Combined wake and suction drags lower than the drag of the plain airfoil were obtained through a range of low lift coefficient by the use of area suction."
Date: October 1952
Creator: Schwartzberg, Milton A. & Braslow, Albert L.
Partner: UNT Libraries Government Documents Department

Investigation of boundary-layer Reynolds number for transition on an NACA 65(215)-114 airfoil in the Langley two-dimensional low-turbulence pressure tunnel

Description: A low-turbulence investigation was made of an aerodynamically smooth NACA airfoil with faired surfaces back to 37 percent chord to determine the magnitude of boundary-layer Reynolds number at various points of transition in flow along different airfoil surfaces. Values of the section drag coefficient were also obtained by means of the wake-survey method.
Date: October 1948
Creator: Braslow, Albert L. & Visconti, Fioravante
Partner: UNT Libraries Government Documents Department

Simplified Method for Determination of Critical Height of Distributed Roughness Particles for Boundary-Layer Transition at Mach Numbers From 0 to 5

Description: Note presenting a simplified method for determination of the critical height of three-dimensional roughness particles required to promote premature transition of a laminar boundary layer on models of airplanes or airplane components in a wind tunnel with zero heat transfer. The method has been applied to various types of configurations in several wind-tunnel investigations.
Date: September 1958
Creator: Braslow, Albert L. & Knox, Eugene C.
Partner: UNT Libraries Government Documents Department

Further Experimental Studies of Area Suction for the Control of the Laminar Boundary Layer on a Porous Bronze NACA 64A010 Airfoil

Description: Note presenting a low-turbulence wind-tunnel investigation of an NACA 64A010 airfoil with a porous surface to determine the reduction in section total-drag coefficient that might be obtained at large Reynolds numbers by the use of area suction. This report primarily deals with additional tests of the same airfoil model equipped with a porous skin of lower porosity.
Date: May 1950
Creator: Braslow, Albert L. & Visconti, Fioravante
Partner: UNT Libraries Government Documents Department

Investigation of Boundary-Layer Reynolds Number for Transition on an NACA 65 (Sub 215)-114 Airfoil in the Langley Two-Dimensional Low-Turbulence Pressure Tunnel

Description: Note presenting a low-turbulence wind-tunnel investigation made of an aerodynamically smooth NACA 65(sub 215)-114 airfoil with faired surfaces back to 37 percent chord to determine the magnitude of the boundary-layer Reynolds number at various positions of transition from laminar to turbulent flow along both airfoil surfaces. In addition to boundary-layer measurements, values of the section drag coefficient were obtained by means of the wake-survey method.
Date: October 1948
Creator: Braslow, Albert L. & Visconti, Fioravante
Partner: UNT Libraries Government Documents Department

Experimental Study of the Effects of Finite Surface Disturbances and Angle of Attack on the Laminar Boundary Layer of an NACA 64A010 Airfoil With Area Suction

Description: Note presenting a low-turbulence wind-tunnel investigation of an NACA 64A010 airfoil section with continuous suction through its porous surfaces to determine its ability to maintain extensive laminar flow behind finite surface disturbances and at angles of attack other than 0 degrees. Generally, application of area suction permitted only a small increase in the size of a finite disturbance required to cause premature boundary-layer transition as compared with the nonsuction airfoil.
Date: October 1952
Creator: Schwartzberg, Milton A. & Braslow, Albert L.
Partner: UNT Libraries Government Documents Department

Studies of the use of Freon-12 as a wind tunnel testing medium

Description: Report presenting a comparison of studies relating to the use of Freon-12 as a substitute medium for air in aerodynamic testing and methods for predicting the aerodynamic characteristics of bodies in air. The Freon charging and recovery system for the Langley low-turbulence pressure tunnel is described.
Date: August 1953
Creator: von Doenhoff, Albert E.; Braslow, Albert L. & Schwartzberg, Milton A.
Partner: UNT Libraries Government Documents Department

Two-dimensional wind-tunnel investigation of 0.20-airfoil-chord plain ailerons of different contour on an NACA 65(sub 1)-210 airfoil section

Description: Report presenting an investigation of three interchangeable sealed-gap 0.20-airfoil-chord plain ailerons of different contour on the NACA 65(sub 1)-210 airfoil section. The three aileron contours tested were the true airfoil contour, straight sides, and a beveled trailing edge. Results regarding the aileron effectiveness, aileron hinge moments, lift, pitching moment, and drag are provided.
Date: December 1945
Creator: Underwood, William J.; Braslow, Albert L. & Cahill, Jones F.
Partner: UNT Libraries Government Documents Department

Two-dimensional wind-tunnel investigation of an approximately 14-percent-thick NACA 66-series-type airfoil section with a double slotted flap

Description: Report presenting a two-dimensional wind tunnel investigation for the purpose of developing a suitable double slotted flap on a 14-percent-thick modified NACA 66-series-type airfoil section. Section aerodynamic characteristics of the airfoil with various double-slotted-flap arrangements are presented. Results regarding the airfoil with the flap retracted and flap deflected are provided.
Date: August 1946
Creator: Braslow, Albert L. & Loftin, Laurence K., Jr.
Partner: UNT Libraries Government Documents Department

Preliminary wind-tunnel investigation of the effect of area suction on the laminar boundary layer over an NACA 64A010 airfoil

Description: Report presenting an investigation in the two-dimensional low-turbulence tunnel on an NACA 64A010 airfoil with permeable surfaces to obtain an indication of the stabilizing effect of area suction on the laminar boundary layer. The surface of the airfoil that was tested had a lot of waves and irregularities, but the theoretically predicted stabilizing effect of area suction on a smooth flat plate was still observed.
Date: April 26, 1948
Creator: Braslow, Albert L.; Visconti, Fioravante & Burrows, Dale L.
Partner: UNT Libraries Government Documents Department