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- Effects of Specific Types of Surface Roughness on Boundary-Layer Transition
- Report presenting tests of two typical low-drag airfoils of 90-inch chord to determine the effects of surface projections, grooves, and sanding scratches on boundary-layer transition. Data were obtained for projections of various sizes and chordwise locations on both low-drag airfoils.
- Experimental Investigation of a New Type of Low-Drag Wing-Nacelle Combination
- Report discusses the results of an experimental investigation of two low-drag wing-nacelle units suitable for use with pusher propellers. The benefits of adding a nacelle to the wing are detailed.
- Flight Investigation at High Speeds of Profile Drag of Wing of a P-47d Airplane Having Production Surfaces Covered With Camouflage Paint
- Report presenting a flight investigation made at high speeds to determine the profile drag of a P-47D airplane wing with production surfaces covered with camouflage paint. The results indicated that a minimum profile-drag coefficient of 0.0097 was attained for lift coefficients from 0.16 to 0.25 at Mach numbers less than 0.67.
- Flight Investigation of Boundary-Layer and Profile-Drag Characteristics of Smooth Wing Sections of a P-47D Airplane
- Report presenting a flight investigation made of boundary-layer and profile-drag characteristics of smooth wing sections of a P-47D airplane. Measurements were made at three stations on the wing: boundary-layer measurements, pressure-distribution measurements, and wake surveys. The results indicated that a minimum profile-drag coefficient of 0.0062 for the smooth section at 63 percent semispan was obtained.
- Flight Investigation of Boundary-Layer Control by Suction Slots on an NACA 35-215 Low-Drag Airfoil at High Reynolds Numbers
- Report presenting an investigation of the effectiveness of suction slots as a means of extending the laminar boundary layer in flight at high Reynolds numbers on an NACA 35-215 airfoil. The results showed that, with a slot spacing of about 5 percent of the chord, the laminar boundary layer could be maintained to or slightly beyond 45 percent of the chord.
- Tests of a Heated Low-Drag Airfoil
- Report discusses the results of an experimental investigation into the NACA 65,2-016 heated wing. Information about the effect of heating on the drag coefficients, Reynolds numbers, and stability of the laminar boundary layer.
- Flight Investigation of Boundary-Layer Transition and Profile Drag of an Experimental Low-Drag Wing Installed on a Figher-Type Airplane
- Report presenting a boundary-layer-transition and profile-drag investigation conducted on an experimental low-drag wing installed on a P-47 airplane designated the XP-47F. Measurements were made at a section outside the propeller slipstream with smooth and with standard camouflage surfaces and on the upper surface of a section in the propeller slipstream with the surface smoothed. Results regarding the right wing section outside the slipstream and left wing section in the propeller slipstream are provided.
- A Profile-Drag Investigation in Flight on an Experimental Fighter-Type Airplane the North American XP-51
- Report discussing the results of an investigation of the North American XP-51 and its low-drag airfoils. Several surface conditions were tested and the profile-drag coefficients were determined. The surface that was smoothened and faired by filling and sanding had the lowest profile-drag coefficient.
- Investigation of the Behavior of Parallel Two-Dimensional Air Jets
- Report presenting an investigation made of the flow downstream from a two-dimensional grid, formed of parallel rods. The two-dimensional character of the flow was insured by end plates normal to the rods and covering the entire flow field. The nature of the flow was determined primarily by means of total-head measurements.
- Preliminary Low-Drag-Airfoil and Flap Data from Tests at Large Reynolds Numbers and Low Turbulence
- Report presenting data on basic thickness and mean-line forms and airfoil test data giving standard airfoil characteristics in tabular and chart form.
- A study of the application of data on various types of flap to the design of fighter brakes
- Report presenting an approximate method of applying the available data on various types of flaps in the design of fighter brakes together with several examples of its use. The computed effects of flap type, size, location, and deflection as well as the effects of altitude and initial velocities on braking characteristics are also shown in some examples using the method to determine various flap arrangements.
- Effect of a Trailing-Edge Extension on the Characteristics of a Propeller Section
- Report presenting a convenient technical method to evaluate changes in the airfoil characteristics resulting from an extension of the chord at the trailing edge of a propeller blade section. The method determines the change in the angle of zero lift, the ideal angle of attack, and the difference in these angles as a function of the angle and length of the trailing-edge extension.
- Variation of peak pitching-moment coefficients for six airfoils as affected by compressibility
- Report presenting pressure distribution tests of six NACA 16-series propeller sections with 1-foot chords in the 8-foot high-speed tunnel to determine the compressibility effects on peak section pitching-moment coefficients. Data is presented as curves of peak section pitching-moment coefficient against Mach number, thickness ratio, and camber. The peak pitching-moment coefficients were found to occur in the regions of positive and negative stall.
- Wind-tunnel investigation of control-surface characteristics 17: beveled-trailing-edge flaps of 0.20, 0.30, and 0.40 airfoil chord on an NACA 0009 airfoil
- Report presenting force tests in two-dimensional flow in the 4- by 6-foot vertical tunnel to determine the aerodynamic characteristics of an NACA 0009 airfoil with flaps having chord at 3 locations of the airfoil chord and three degrees of the beveled trailing edges. The results indicated that, with a smooth leading edge, the increased trailing-edge angle on the flaps with sealed gaps decreased the slope of the control-fixed lift curve and the lift effectiveness.
- Effects of Compressibility on the Maximum Lift Characteristics and Spanwise Load Distribution of a 12-Foot-Span Fighter-Type Wing of NACA 230-Series Airfoil Sections
- Lift characteristics and pressure distribution for a NACA 230 wing were investigated for an angle of attack range of from -10 to +24 degrees and Mach range of from 0.2 to 0.7. Maximum lift coefficient increased up to a Mach number of 0.3, decreased rapidly to a Mach number of 0.55, and then decreased moderately. At high speeds, maximum lift coefficient was reached at from 10 to 12 degrees beyond the stalling angle. In high-speed stalls, resultant load underwent a moderate shift outward.
- Wind-Tunnel Investigation of Control-Surface Characteristics 15: Various Contour Modifications of a 0.30-Airfoil-Chord Plain Flap on an NACA 66(215)-014 Airfoil
- Report presenting force-test measurements in two-dimensional flow made in the 4- by 6-foot vertical tunnel to determine the aerodynamic characteristics of an NACA 66(215)-014 airfoil equipped with true-contour, straight-contour, and beveled-trailing-edge flaps with chords 30 percent of the airfoil chord. The results are presented in the form of aerodynamic section characteristics for several flap deflections and for a sealed and unsealed gap at the flap nose.
- Wind-Tunnel Investigation of an NACA 23021 Airfoil With Two Sizes of Balanced Split Flaps
- Report presenting an investigation in the 7- by 10-foot wind tunnel of a large-chord NACA 23021 airfoil with a 15-percent-chord and a 25-percent-chord balanced split flap of Clark Y profile, to determine the aerodynamic section characteristics of the airfoil-flap combinations as affected by the size, nose location, and deflection of the flaps.
- Preliminary Report on the Characteristics of the N.A.C.A. 4400R Series Airfoils
- Report presenting tests made in the variable-density wind tunnel of airfoils of the NACA 4400 series modified by reflex at the trailing edge designed to reduce the pitching moment to the value of -0.03. The modified airfoils are designated the NACA 4400R series.
- Characteristics of Naca 4400R Series Rectangular and Tapered Airfoils, Including the Effect of Split Flaps
- "At the request of the Bureau of Aeronautics, Navy Department, tests were made in the variable-density wind tunnel of a tapered wing of 3-10-18 plan form and based on the NACA 4400R series sections. The wing was also tested with 0.2 chord split flaps, deflected 60 degrees, in the center of the wing and having flat span to wing span ratios of 0.3, 0.5, 0.7, and 1.0, respectively" (p. 1).
- Wind-tunnel investigation of perforated split flaps for use as dive brakes on a rectangular NACA 23012 airfoil
- Report presenting an investigation of the aerodynamic characteristics of a rectangular NACA 23012 airfoil with single and double perforated split flaps in the NACA 7- by 10-foot wind tunnel. A large range of flap spans and deflections and a large range of spanwise and chordwise locations of the flaps were investigated. Results regarding the double split flaps, single split flaps, diving speed, and aileron control are provided.
- Experimental verification of a simplified vee-tail theory and analysis of available data on complete models with vee tails
- Report presenting an analysis of available data on vee-tail surfaces. The analysis indicated that a vee tail designed to provide values of stability and control parameters equal to those provided by a conventional tail would probably provide no reduction in area unless the conventional vertical tail is in a bad canopy wake or unless the vee tail has a higher effective aspect ratio than the conventional vertical and horizontal tails.
- Determination of the Effect of Horizontal-Tail Flexibility on Longitudinal Control Characteristics
- Report presenting an iteration method for determining the longitudinal control characteristics of a flexible horizontal tail. The method permits factors such as the actual spanwise variation of elasticity and the aerodynamic induction effects due to three-dimensional flow to be accounted for to any degree of accuracy needed. An analysis is also included of the effects of horizontal-tail flexibility on the tail effectiveness, the hinge-moment characteristics, and the control-force gradients in a dive recovery for two modern fighter airplanes.
- Analysis of Available Data on Control Surfaces Having Plain-Overhang and Frise Balances
- From Introduction: "The present paper deals with control surfaces having plain-overhang and Frise balances."
- Effect of Compressibility on Pressure Distribution Over an Airfoil With a Slotted Frise Aileron
- Pressure distribution measurements were made over an airfoil with slotted Frise aileron up to 0.76 Mach at various angles of attack and aileron defections. Section characteristics were determined from these pressure data. Results indicated loss of aileron rolling power for deflections ranging from -12 Degrees to -19 Degrees.
- Aerodynamic Characteristics of a Slot-Lip Aileron and Slotted Flap for Dive Brakes
- From Introduction: "As a part of this investigation, a study is being made of test results obtained during the development of devices designed primarily for other purposes, such as high lift or lateral control, but which may also be used for dive control. These results have been reanalyzed and are herein presented in a form that should make them convenient for design purposes."
- Wind-tunnel tests of a blunt-nose aileron with beveled trailing edge on an NACA 66(215)-216 airfoil with several modifications of aileron nose and adjacent airfoil contour
- Report presenting an investigation of ailerons with a beveled trialing edge and a blunt-nose overhang of 35 percent aileron chord on an NACA 66(215)-26 airfoil in two-dimensional flow. Five configurations were tested with various modifications of the aileron nose and adjacent airfoil contour to determine the effect of modifications on lift and aileron hinge-moment characteristics.
- Analysis of available data on the effectiveness of ailerons without exposed overhang balance
- From Introduction: "As a part of the general lateral-control investigation by the NACA, the large amount of two- and three-dimensional data on the rolling effectiveness of ailerons without exposed overhang balance is collected and analyzed in the present paper."
- Wind-tunnel tests of ailerons at various speeds 2: ailerons of 0.20 airfoil chord and true contour with 0.60 aileron-chord sealed internal balance on the NACA 66,2-216 airfoil
- Report presenting hinge-moment, lift, pressure difference across the balance, and pressure-distribution measurements in the two-dimensional test section of the stability tunnel on a 0.60 aileron-chord sealed internal-balance aileron on a specified NACA airfoil. The primary test objective was to determine the effect of speed on the action of the aileron.
- Wind-Tunnel Tests of Ailerons at Various Speeds 3: Ailerons of 0.20 Airfoil Chord and True Contour With 0.35-Aileron-Chord Frise Balance on the NACA 23012 Airfoil
- Report presenting hinge moment, lift, and pressure-distribution measurements made on a Frise aileron on an NACA 23012 airfoil in the two-dimensional test section of the stability tunnel. Speeds up to 360 miles per hour corresponding to a Mach number of about 0.470 were used.
- Wind Tunnel Tests of Ailerons at Various Speeds 4: Ailerons of 0.20 Airfoil Chord and True Contour With 0.35 Aileron-Chord Extreme Blunt-Nose Balance on the NACA 23012 Airfoil
- Report presenting tests made on an NACA 23012 airfoil fitted with a 20-percent-chord, true-contour aileron with 35-percent-chord, extreme blunt-nose balance. The primary purpose of the investigation was to determine the variation of the aerodynamic characteristics of this type of aileron with airspeed; the effect of variations of gap width and balance-nose radii was also investigated. Results regarding hinge moments, lift, and pitching-moment coefficients are provided.
- Wind Tunnel Tests of Ailerons at Various Speeds 1: Ailerons of 0.20 Airfoil Chord and True Contour With 0.35 Aileron-Chord Extreme Blunt Nose Balance on the NACA 66,2-216 Airfoil
- "Hinge-moment, lift, and pressure-distribution measurements were made in the two-dimensional test section of the NACA stability tunnel on a blunt-nose balance-type aileron on an NACA 66,2-216 airfoil at speeds up to 360 miles per hour corresponding to a Mach number of 0.475. The tests were made primarily to determine the effect of speed on the action of this type of aileron. The balance-nose radii of the aileron were varied from 0 to 0.02 of the airfoil chord and the gap width was varied from 0.0005 to 0.0107 of the airfoil chord. Tests were also made with the gap sealed" (p. 1).
- Collection of Balanced-Aileron Test Data
- "Test data of balanced ailerons have been collected from NACA and British sources. These data, which are presented in the form of charts, are grouped as A - ailerons with Frise balances, B - ailerons with blunt-nose balances, C - ailerons with internal balances, D - ailerons with contour modifications, and E - ailerons with tabs. Results of flight tests and of wind-tunnel tests in both two- and three-dimensional flow are presented but no correlation nor resume of the data has been included" (p. 1).
- Wind-tunnel investigation of a plain aileron with thickened and beveled trailing edges on a tapered low-drag wing
- Report presenting an investigation in the 7- by 10-foot tunnel of various modifications of the trailing-edge portion of a 0.20-chord plain aileron on a partial-span model of a tapered low-drag wing. The modifications tested included various amounts of symmetrical and unsymmetrical thickening and beveling of the aileron trailing edge. Results regarding coefficients and corrections, characteristics with ailerons neutral, characteristics with ailerons deflected, aileron trim characteristics, and estimated aileron-control characteristics are provided.
- Flight Investigation of Boundary-Layer Transition and Profile Drag of an Experimental Low-Drag Wing Installed on a Fighter-Type Airplane
- Report presenting a boundary-layer transition and profile-drag investigation on an experimental low-drag wing installed on a P-47 airplane designated the XP-47F and supplied by the Army Air Forces. Measurements were made at a section outside the propeller slipstream with smooth and with standard camouflage surfaces and on the upper surface of a section in the propeller slipstream with the surface smoothed.
- Flight Tests of Dive-Recovery Flaps on an XP-51 Airplane
- Report presenting a flight investigation made to determine the effectiveness of dive-recovery flaps installed on the XP-51 airplane as a safety device for recovery from contemplated terminal-velocity dives. The flap installation is described and results are presented of measurements obtained during stick-free pull-ups and pull-outs made by deflecting the dive-recovery flaps to two selected values of flap angle .
- Preliminary Tests in the NACA Tank to Investigate the Fundamental Characteristics of Hydrofoils
- A preliminary investigation made to study the hydrodynamic properties and general behavior of simple hydrofoils. Six plain, rectangular hydrofoils were tested in a tank at various speeds, angles of attack, and depths below the water surface. The results are presented as curves of the lift and drag coefficients plotted against speed for various angles of attack and depths for which the hydrofoils were tested.
- Estimation of Pressures on Cockpit Canopies, Gun Turrets, Blisters, and Similar Protuberances
- Report presenting methods for estimating pressure distributions over protuberances such as cockpit canopies, gun turrets, blisters, scoops, and sighting domes. The methods are applied to the estimation of the pressure distributions over spherical segment and faired gun turrets and over the protuberances on the Brewster SB2A-1 airplane. The effects of compressibility, interference, and flow separation are discussed.
- Flight Investigation of Wing-Gun Fairings on a Fighter Type Airplane
- Description is given of flight tests conducted on gun fairings, designed to correct the detrimental effects of the projecting and submerged wing guns on an F4F-3 fighter. It was found that the installation of unfaired guns on a clean wing resulted in a premature stall that increased the stalling speed in the carrier-approach and landing conditions of flight by suitably fairing the guns, it was possible to reduce the stalling speeds to values approaching very nearly the clean-wing values.
- An Investigation of Hydrofoils in the NACA Tank 1: Effect of Dihedral and Depth of Submersion
- Tests were conducted on hydrofoil assemblies approximating an arrangement for use under seaplanes or surface boats. A series of hydrofoils, each supported by two struts, was towed at various depths ranging from partial submersions to a depth of 5-chord lengths. At depths greater than 4 or 5 chords, the influence of the surface of the water is small; hydrofoils operating at low speed will have characteristics similar to those of airfoils of the same section.
- Wind-Tunnel Investigation of a High-Critical-Speed Fuselage Scoop Including the Effects of Boundary Layer
- Report presenting a large air scoop designed for high critical speed, which has been tested in the 8-foot high-speed tunnel on the fuselage of a scale fighter-type airplane. The effects of boundary layer on scoop characteristics were found to be important at all inlet-velocity ratios. Results regarding the boundary-layer surveys, characteristics of original scoop installation, and characteristics of scoop with boundary-layer passage are provided.
- High-speed drag tests of several fuselage shapes in combination with a wing
- Drag testing was conducted in the high-speed wind tunnel of 23 conditions combining six streamline shapes and three conventional cowling-fuselage bodies. All of the models were tested in combination with a wing in order to include wing-fuselage interference effects. The critical speeds of combinations tested were, in general, determined by the wing-fuselage juncture.
- Wind Tunnel Tests of a Submerged-Engine Fuselage Design
- Report presenting tests conducted in the 8-foot high-speed wind tunnel of a scale model pursuit-type fuselage with practicable internal duct arrangement designed to meet all of the air requirements of a 1000-horsepower radial engine submerged at the maximum section. The results showed that the required internal flow can be obtained with negligible ducting losses provided that basic principles are observed in designing the air passages.
- High-Speed Wind-Tunnel Tests of Gun Openings in the Nose of the Fuselage of a 1/4-Scale Model
- "In connection with recent tests of a 1/4-scale model pursuit airplane in the NACA 8-foot high-speed tunnel, gun openings having low drag were developed for installation in the nose of the fuselage. The increase in the fuselage-drag coefficient for the final form of openings was 0.0132 at a Mach number of 0.69 and at an angle of attack of 0 degrees. The corresponding drag coefficient based on the wing area was about 0.0005. The critical speed of the airplane was not affected by the gun openings" (p. 1).
- A flight investigation of NACA aileron modifications for the improvement of the lateral control characteristics of a high-speed fighter airplane
- Report presenting a flight investigation to improve the lateral control of a high-speed fighter airplane. Testing occurred with the original ailerons and a set of modified ailerons, which consisted of an increased balance chord and increased nose radius. The modified ailerons appear to offer a solution to the problem of aileron overbalance and oscillation in high-speed dives.
- Comparison of fixed-stabilizer, adjustable- stabilizer and all-movable horizontal tails
- Report presenting an analysis to compare longitudinal stability and control characteristics obtained with a conventional fixed-stabilizer, an adjustable-stabilizer, and an all-movable horizontal tail. The tail-area requirements, control forces required in the critical landing condition, static margin, control-force gradients in a dive recovery, and elevator-free stability are investigated.
- Effect of leakage past aileron nose on aerodynamic characteristics of plain and internally balanced ailerons on NACA 66(215)-216, a = 1.0 airfoil
- Report presenting an investigation in two-dimensional flow to determine the effect of leakage past the aileron nose on the aerodynamic characteristics of ailerons. The effects of amount and type of leakage, aileron contour, and Mach and Reynolds number are investigated.
- Wind-Tunnel Investigation of Control-Surface Characteristics: [Part] 18 - A Linked Overhang Aerodynamic Balance
- Report presenting wind-tunnel testing in two-dimensional flow to investigate the aerodynamic characteristics of a flap balanced by a large overhang linked to deflect more slowly than the flap. Three lengths of blunt-nose overhang were tested linked to a 0.30-airfoil-chord straight-contour flap on an NACA 66-009 airfoil. Results regarding lift, hinge moment, drag, pitching moment, and practical considerations are provided.
- Wind-tunnel investigation of control-surface characteristics 19: a double flap with an overhang and an internal aerodynamic balance
- Report presenting wind-tunnel tests in two-dimensional flow to investigate the aerodynamic characteristics of a double flap with an internal and overhang balance. Three sizes of each type of balance were tested with three relative rates of deflection of the two flaps. Results regarding lift, hinge moment, drag, and pitching moment are provided.
- Wind-Tunnel Investigation of Shielded Horn Balances and Tabs on a 0.7-Scale Model of XF6F Vertical Tail Surface
- Results of subject tests indicate the difficulty of obtaining closely balanced rudder surfaces for most tail assemblies with shielded horns and maintaining a near zero rate-of-change of hinge-moment coefficient without an additional balancing device. A comparison is made between shielded and unshielded horn test results. Pressure distribution and tuft tests of flow over different shaped horns showed higher critical speed for medium-taper nosed horn. The trim tab nose shape had little effect on tab test results.
- Wind-tunnel investigation of control-surface characteristics 13: various flap overhangs used with a 30-percent-chord flap in an NACA 66-009 airfoil
- Report presenting force tests in two-dimensional flow made on an NACA 66-009 airfoil with a flap having a chord 30 percent of the airfoil chord and a tab having a chord 20 percent of the flap chord. A plain flap and flaps having overhangs of 35 and 50 percent of the flap chord were tested with two gap variations: sealed and unsealed. Results regarding lift, flap hinge moments, pitching moments, drag, and tab characteristics are provided.