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An instrument for estimating tautness of doped fabrics on aircraft

Description: Technical note presenting the design and use of a spring-loaded tautness meter that can be used in both horizontal and vertical positions to compare the tautness of various panels. Results of tests made on the fabric coverings of various airplanes are reported and discussed.
Date: September 1939
Creator: Kline, Gordon M. & Schiefer, Herbert F.
Partner: UNT Libraries Government Documents Department
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Resume of Air-Load Data on Slats and Flaps

Description: "A resume of the generally available test data regarding air loads on slats and flaps is presented and data attained up to the fall of 1938 are included. The data are given in the form of N.A.C.A. standard coefficients of air forces and moments on the lift-increasing device and, when available, the aerodynamic characteristics of the combined wing and high-lift device are included. Slats of the Handley Page type, fixed auxiliary airfoils, and flaps of several different types are covered" (p. 1).
Date: March 1939
Creator: Wenzinger, Carl J. & Rogallo, Francis M.
Partner: UNT Libraries Government Documents Department
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Some fundamental considerations in regard to the use of power in landing an airplane

Description: From Summary: "This note is concerned with the effect of power on landing speed and apparent maximum lift coefficient. It is shown that when secondary effects are neglected, the maximum available increase in lift due to power is equal to the thrust being developed. If the increase in lift due to power is expressed in coefficient form, very high values may be shown under conditions which, on analysis, are found to be wholly impracticable in flight."
Date: March 1939
Creator: Diehl, Walter S.
Partner: UNT Libraries Government Documents Department
open access

Adhesion of Ice in Its Relation to the De-Icing of Airplanes

Description: From Summary: "The various possible means of preventing ice adhesion on airplane surfaces are critically reviewed. Results are presented of tests of the adhesives forces between ice and various solid and liquid forces. It is concluded that the de-icing of airplane wings by heat from engine exhaust shows sufficient promise to warrant full-scale tests. For propellers, at least, and possibly for certain small areas such as windshields, radio masts, etc. the use of de-icing or adhesion-preventing l… more
Date: August 1939
Creator: Rothrick, A. M. & Selden, R. F.
Partner: UNT Libraries Government Documents Department
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Comparison of Profile-Drag and Boundary-Layer Measurements Obtained in Flight and in the Full-Scale Wind Tunnel

Description: "The effect of the existing turbulence in the full scale tunnel was determined from measurements of the profile drag of an N-22 section by the momentum method under corresponding conditions in flight and the tunnel. The transition-point location on the upper surface of the air-foil was also determined from velocity surveys in the boundary layer. The measurements were made at section lift coefficients from 0.480 to 0.635 with a range of Reynolds Numbers from 4,600,000 to 3,900,000. The results s… more
Date: March 1939
Creator: Goett, Harry J. & Bicknell, Joseph
Partner: UNT Libraries Government Documents Department
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Tandem Air Propellers

Description: "Tests of 2-blade, adjustable-pitch, counter rotating tandem model propellers, adjusted to absorb equal power at maximum efficiency, were made at Stanford University. The characteristics, for 15 degrees, 25 degrees, 35 degrees, and 45 degrees pitch settings at 0.75 R of the forward propeller and for 8-1/2 percent, 15 percent, and 30 percent diameter spacings, were compared with those of 2-blade and 4-blade propellers of the same blade form" (p. 1).
Date: February 1939
Creator: Lesley, E. P.
Partner: UNT Libraries Government Documents Department
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Local Instability of Centrally Loaded Columns of Channel Section and Z-Section

Description: "Charts are presented for the coefficients in formulas for the critical compressive stress at which cross-sectional distortion begins in a thin-wall member with either a channel section or a Z-section with identical flanges. The energy method of Timoshenko was used in the theoretical calculations required for the construction of the charts. The deflection equations were carefully selected to give good accuracy. The calculation of the critical compressive stress at stresses beyond the elastic ra… more
Date: August 1939
Creator: Lundquist, Eugene E.
Partner: UNT Libraries Government Documents Department
open access

Torsional stability of aluminum alloy seamless tubing

Description: Torsion tests were made on 51ST aluminum-alloy seamless tubes having diameter-to-thickness ratios of from 77 to 139 and length-to-diameter ratios of from 1 to 60. The torsional strengths developed in the tubes which failed elastically (all tubes having lengths greater than 2 to 6 times the diameter) were in most cases within 10 percent of the value indicated by the theories of Donnel, Timoshenko, and Sturm, assuming a condition of simply supported ends.
Date: March 1939
Creator: Moore, R. L. & Paul, D. A.
Partner: UNT Libraries Government Documents Department
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The Frequency of Torsional Vibration of a Tapered Beam

Description: "A solution for the equation of torsional vibration of tapered beams has been found in terms of Bessel functions for beams satisfying the following conditions: (a) the cross sections along the span are similar in shape; and (b) the torsional stiffness of a section can be expressed as a power of a linear function of distance along the span. The method of applying the analysis to actual cases has been described. Charts are given from which numerical values can be immediately obtained for most cas… more
Date: March 1939
Creator: Coleman, Robert P.
Partner: UNT Libraries Government Documents Department
open access

Propeller Tests to Determine the Effect of Number of Blades at Two Typical Solidities

Description: "Propellers with equal total blade area, but with different numbers, were tested at Stanford University. The tests show generally that, for equal total blade area, propellers with the larger number of blades absorb the greater power and, provided hubs have equal drag, develop the higher efficiency. It is shown that the differences found are in agreement, qualitatively, with what might be predicted from simple blade-element theory" (p. 1).
Date: April 1939
Creator: Lesley, E. P.
Partner: UNT Libraries Government Documents Department
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Tests of an N.A.C.A. 23012 Airfoil with a slotted deflector flap

Description: Section aerodynamic characteristics of a large-chord N.A.C.A. 23012 airfoil with a slotted deflector flap were obtained in the N.A.C.A. 7- by 10-foot wind tunnel. The characteristics of an N.A.C.A. slotted flap and of a simple split flap are included for comparison. The slotted deflector flap was found to have a somewhat lower maximum lift coefficient and somewhat higher drag at high lift coefficients than the N.A.C.A. slotted flap. The high drag of the open slot with the deflector flap neutral… more
Date: April 1939
Creator: House, R. O.
Partner: UNT Libraries Government Documents Department
open access

Physical Properties of Synthetic Resin Materials

Description: "A study was made to determine the physical properties of synthetic resins having paper, canvas, and linen reinforcements, and of laminated wood impregnated with a resin varnish. The results show that commercial resins have moduli of elasticity that are too low for structural considerations. Nevertheless, there do exist plastics that have favorable mechanical properties and, with further development, it should be possible to produce resin products that compare favorably with the light-metal all… more
Date: March 1939
Creator: Fishbein, Meyer
Partner: UNT Libraries Government Documents Department
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The Effects of Surface Waviness and of Rib Stitching on Wing Drag

Description: "Surface waviness and rib stitching have been investigated as part of a series of tests to determine the effects on wing drag of common surface irregularities. The tests were made in the N.A.C.A. 8-foot high-speed wind tunnel at Reynolds Numbers up to 17,000,000. The results of the tests showed that the waviness common to airplane wings will cause no serious increase in drag unless the waviness exists on the forward part of the wing, where it may cause premature transition or premature compress… more
Date: August 1939
Creator: Hood, Manley J.
Partner: UNT Libraries Government Documents Department
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The Effects of Some Surface Irregularities on Wing Drag

Description: "The N.A.C.A. has conducted tests to provide more complete data than were previously available for estimating the effects of common surface irregularities on wing drag. The irregularities investigated included: brazier-head and countersunk rivets, spot welds, several types of sheet-metal joints, and surface roughness. Tests were also conducted to determine the over-all effect of manufacturing irregularities incidental to riveted aluminum alloy and to spot-welded stainless-steel construction" (p… more
Date: March 1939
Creator: Hood, Manley J.
Partner: UNT Libraries Government Documents Department
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Tank Tests to Determine the Effects of the Chine Flare of a Flying-Boat Hull N.A.C.A. Model Series 62 and 69

Description: Note presenting testing of twenty-two models of flying-boat hulls for the purpose of determining the effects on water resistance and spray of 13 variations in the transverse section of the bottom of the forebody and of three variations in the form of the afterbody. Generally, the effect of chine flare on the resistance was small, although the resistance of force with chine flare was generally less than the resistance of the form without chine flare.
Date: August 1939
Creator: Bell, Joe W. & Olson, Roland E.
Partner: UNT Libraries Government Documents Department
open access

A simplified method for the calculation of airfoil pressure distribution

Description: From Summary: "A method is presented for the rapid calculation of the pressure distribution over an airfoil section when the normal-force distribution and the pressure distribution over the "base profile" (i.e., the profile of the same airfoil were the camber line straight and the resulting airfoil at zero angle of attack) are known. This note is intended as a supplement to N.A.C.A. Report Nos. 631 and 634 wherein methods are presented for the calculation of the normal-force distribution over p… more
Date: May 1939
Creator: Allen, H. Julian
Partner: UNT Libraries Government Documents Department
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A semi-graphical method for analyzing strains measured on three or four gage lines intersecting at 45 degrees

Description: Report presenting a method for analyzing strains measured on three or four gage lines intersecting at 45 degrees, which helps determine the state of stress at a point on a plane. An equation for adjustment factor and a master curve is provided, which can be memorized and easily used in the future.
Date: May 1939
Creator: Hill, H. N.
Partner: UNT Libraries Government Documents Department
open access

A Comparison of Ignition Characteristics of Diesel Fuels as Determined in Engines and in a Constant-Volume Bomb

Description: Ignition-lag data have been obtained for seven fuels injected into heated, compressed air under conditions simulating those in a compression-ignition engine. The results of the bomb tests have been compared with similar engine data, and the differences between the two sets of results are explained in terms of the response of each fuel to variations in air density and temperature.
Date: June 1939
Creator: Selden, Robert F.
Partner: UNT Libraries Government Documents Department
open access

A preliminary study of the prevention of ice on aircraft by the use of engine-exhaust heat

Description: "An investigation was made in the N.A.C.A. ice tunnel at air temperatures from 20 degrees to 28 degrees Fahrenheit and at a velocity of 80 miles per hour to determine whether ice formations on a model wing could be prevented by the use of the heat from the engine-exhaust gas. Various spanwise duct systems were tested in a 6-foot-chord N.A.C.A. 23012 wing model. The formation of ice over the entire wing chord was prevented by the direct heating of the forward 10 percent of the wing by hot air, w… more
Date: June 1939
Creator: Rodert, Lewis A.
Partner: UNT Libraries Government Documents Department
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Wind-tunnel investigation of an N.A.C.A. 23012 airfoil with two arrangements of a wide-chord slotted flap

Description: "An investigation has been made in the N.A.C.A. 7- by 10-foot wind tunnel of a large-chord N.A.C.A. 23012 airfoil with several arrangements of a 40-percent-chord slotted flap to determine the section aerodynamic characteristics of the airfoil as affected by slot shape, flap location, and flap deflection. The flap positions for maximum lift, the polar for arrangements considered favorable for take-off and climb, and the complete section aerodynamic characteristics for selected optimum arrangemen… more
Date: June 1939
Creator: Harris, Thomas A.
Partner: UNT Libraries Government Documents Department
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Experimental study of deformation and of effective width in axially loaded sheet-stringer panels

Description: From Summary: "The deformation of two sheet-stringer panels subjected to end compression under carefully controlled end conditions was measured at a number of points and at a number of loads, most of which were above the load at which the sheet had begun to buckle. The two panels were identical except for the sheet, which was 0.70-inch 24st alclad for specimen 1 and 0.025-inch 24st aluminum alloy for specimen 6. A technique was developed for attaching Tuckerman optical strain gauges to the shee… more
Date: February 1939
Creator: Ramberg, Walter; McPherson, Albert E. & Levy, Sam
Partner: UNT Libraries Government Documents Department
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Circulation Measurements About the Tip of an Airfoil During Flight Through a Gust

Description: "Measurements were made of the circulation about the rectangular tip of a short-span airfoil passing through an artificial gust of known velocity gradient. A Clark Y airfoil of 30-centimeter chord was mounted on a whirling arm and moved at a velocity of 29 meters per second over a vertical gust with a velocity of nearly 7 meters per second. Flow angles were measured with a hot-wire apparatus" (p. 1).
Date: February 1939
Creator: Kuethe, Arnold M.
Partner: UNT Libraries Government Documents Department
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Hydrodynamic and aerodynamic tests of a family of models of seaplane floats with varying angles of dead rise: N.A.C.A. Models 57-A, 57-B, and 57-C

Description: Three models of V-bottom floats for twin-float seaplanes (N.A.C.A. models 57-A, 57-B, and 57-C) having angles of dead rise of 20 degrees, 25 degrees, and thirty degrees, respectively, were tested in the N.A.C.A. tank and in the N.A.C.A. 7- by 10-foot wind tunnel. Within the range investigated, the effect of angle of dead rise on water resistance was found to be negligible at speeds up to and including the hump speed, and water resistance was found to increase with angle of dead rise at planing … more
Date: July 1939
Creator: Parkinson, John B.; Olson, Roland E. & House, Rufus O.
Partner: UNT Libraries Government Documents Department
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