The Knock-Limited Performance of S Reference Fuel Plus 2 Milliliters of Triethylthallium Per Gallon (open access)

The Knock-Limited Performance of S Reference Fuel Plus 2 Milliliters of Triethylthallium Per Gallon

Report discusses the results of testing of thallium as an antiknock agent in an internal-combustion engine. From Introduction: "On a weight basis, the thallium vapors were found to have several times the antiknock value of tetraethyl lead, which was added to the fuel. The amount of thallium vapor necessary to raise the antiknock properties of a gasoline up to exact equivalence with a benzol-gasoline mixture was determined in these engine tests."
Date: November 1945
Creator: Meyer, Carl L.
System: The UNT Digital Library
Ditching Tests With 1/10-Size Model of the Army a-20a Airplane 1: Calm-Water Tests in NACA Tank No.2 (open access)

Ditching Tests With 1/10-Size Model of the Army a-20a Airplane 1: Calm-Water Tests in NACA Tank No.2

Report presenting tests to determine the behavior of landplanes when they are forced to land on the water. The report is incomplete.
Date: November 1943
Creator: Dawson, John R. & Jarvis, George A.
System: The UNT Digital Library
On the Flow of a Compressible Fluid by the Hodography Method 2: Fundamental Set of Particular Flow Solutions of the Chaplygin Differential Equation (open access)

On the Flow of a Compressible Fluid by the Hodography Method 2: Fundamental Set of Particular Flow Solutions of the Chaplygin Differential Equation

Report presenting the utilization of the differential equation of Chaplygin's jet problem to give a systematic development of particular solutions of the hodograph flow equations, which extends the treatment of Chaplygin into the supersonic range and completes the set of particular solutions. The solutions serve to place on a reasonable basis the use of velocity correction formulas for the comparison of incompressible and compressible flows.
Date: November 1944
Creator: Kaplan, Carl
System: The UNT Digital Library
The effect of exhaust-stack shape on the design and performance of the individual cylinder exhaust-gas jet-propulsion system (open access)

The effect of exhaust-stack shape on the design and performance of the individual cylinder exhaust-gas jet-propulsion system

Report presenting tests on a single-cylinder, air-cooled engine to determine the effect of several different exhaust-stack shapes on the design and performance of the individual cylinder exhaust-gas jet-propulsion systems. Results regarding the effect of nozzle area and stack shape on exhaust-gas jet thrust, effect of nozzle area and stack shape on overall performance for the S-shape, the 90 degree bend, and the 180 degree bend, the effect on the shape on engine power and volumetric efficiency, and the effect of a branched stack on engine power are provided.
Date: November 1942
Creator: Turner, L. Richard & Humble, Leroy V.
System: The UNT Digital Library
The problem of longitudinal stability and control at high speeds (open access)

The problem of longitudinal stability and control at high speeds

Report discussing the difficulty in pulling of high-speed dives, which is primarily due to the effect of compressibility on the lift of the wing. Some of the means described for providing increased longitudinal control include auxiliary flaps and a controllable stabilizer.
Date: November 1943
Creator: Hood, Manley J. & Allen, H. Julian
System: The UNT Digital Library
The Flow of a Compressible Fluid Past a Curved Surface (open access)

The Flow of a Compressible Fluid Past a Curved Surface

Report presenting an iteration method employed to obtain the flow of a compressible fluid past a curved surface. For small Mach numbers and thin shapes, the results obtained by the iteration process agree with those obtained by the Poggi method.
Date: November 1943
Creator: Kaplan, Carl
System: The UNT Digital Library
Secondary Stresses in Open Box Beams Subjected to Torsion (open access)

Secondary Stresses in Open Box Beams Subjected to Torsion

In open box beams subjected to torsion, secondary stresses arise owing to lateral bending of the spar caps. The present paper outlines a simple method for estimating the magnitude of these stresses and gives the results of tests of an open box beam in the neighborhood of a discontinuity where the cover changed from the top to the bottom of the box.
Date: November 1944
Creator: Kuhn, Paul; Batdorf, S. B. & Brilmyer, Harold G.
System: The UNT Digital Library
Flight Investigation at High Mach Numbers of Several Methods of Measuring Static Pressure on an Airplane Wing (open access)

Flight Investigation at High Mach Numbers of Several Methods of Measuring Static Pressure on an Airplane Wing

Report discusses an investigation into static pressures in subsonic and supersonic flow over an airplane wing as measured by static-pressure tubes, a static-pressure belt, and orifices flush with the wing surface. The results obtained from the three types of measuring devices and a comparison to theoretical calculations are presented.
Date: November 1944
Creator: Zalovcik, John A. & Daum, Fred L.
System: The UNT Digital Library
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 (open access)

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.
Date: November 1945
Creator: Pearson, E. O., Jr.; Evans, A. J. & West, F. E., Jr.
System: The UNT Digital Library
Wind-Tunnel Investigation of Perforated Split Flaps for Use as Dive Brakes on a Tapered NACA 23012 Airfoil (open access)

Wind-Tunnel Investigation of Perforated Split Flaps for Use as Dive Brakes on a Tapered NACA 23012 Airfoil

Aerodynamic characteristics of a tapered NACA 23012 airfoil with single and double perforated split flaps have been determined in the NACA 7- by 10-foot wind tunnel. Dynamic pressure surveys were made behind the airfoil at the approximate location of the tail in order to determine the extent and location of the wake for several of the flap arrangements. In addition, computations have been made of an application of perforated double split flaps for use as fighter brakes. The results indicated that single or double perforated split flaps may be used to obtain satisfactory dive control without undue buffeting effects and that single or double perforated split flaps may also be used as fighter brakes. The perforated split flaps had approximately the same effects on the aerodynamic and wake characteristics of the tapered airfoil as on a comparable rectangular airfoil.
Date: November 1941
Creator: Purser, Paul E. & Turner, Thomas R.
System: The UNT Digital Library
Wind-Tunnel Development of a Plug-Type Spoiler-Slot Aileron for a Wing With a Full-Span Slotted Flap and a Discussion of Its Application (open access)

Wind-Tunnel Development of a Plug-Type Spoiler-Slot Aileron for a Wing With a Full-Span Slotted Flap and a Discussion of Its Application

Report presenting an investigation in the NACA 7- by 10-foot wind tunnel of several arrangements of a plug-type, spoiler-slot aileron on an NACA 23012 airfoil with a full-span slotted flap. The results indicated that a plug-type, spoiler-slot aileron probably has negligible drag in the neutral position and will provide satisfactory lateral control for airplanes equipped with full-span slotted flaps.
Date: November 1941
Creator: Rogallo, Francis M. & Swanson, Robert S.
System: The UNT Digital Library
Critical shear stress of an infinitely long flat plate with equal elastic restraints against rotation along the parallel edges (open access)

Critical shear stress of an infinitely long flat plate with equal elastic restraints against rotation along the parallel edges

Report presenting a chart for the values of the coefficient in the formula for the critical shear stress at which buckling may be expected to occur in an infinitely long flat plate with parallel edges. An approximate method for the evaluation of the critical shear stress when the elastic restraints on the two parallel edges are not equal is also presented.
Date: November 1943
Creator: Stowell, Elbridge Z.
System: The UNT Digital Library
Estimates of the Vertical-Tail Loads of a Bell P-63A-1 Airplane (AAF No. 42-68889) in Accelerated Rolling Maneuvers Based on Flight Tests With Two Vertical-Tail Arrangements (open access)

Estimates of the Vertical-Tail Loads of a Bell P-63A-1 Airplane (AAF No. 42-68889) in Accelerated Rolling Maneuvers Based on Flight Tests With Two Vertical-Tail Arrangements

Report discussing the results of using an enlarged vertical tail on a P-63A-1 on directional stability. The tests included measurements of the amount of sideslip at various speeds and normal accelerations. Potential required modifications for increased performance using the larger tail are also described.
Date: November 30, 1944
Creator: Johnson, Harold I.
System: The UNT Digital Library
Adjustment of Stick Force by a Nonlinear Aileron-Stick Linkage (open access)

Adjustment of Stick Force by a Nonlinear Aileron-Stick Linkage

Report presenting an application of the principle of aileron-stick forces and mechanical advantage to an aileron installation in which the stick forces are small over the low-deflection range and excessively large at full deflection.
Date: November 1942
Creator: Lowry, John G.
System: The UNT Digital Library
Wind-Tunnel Tests of a Piston-Type Control Booster on an Airfoil and Aileron Model (open access)

Wind-Tunnel Tests of a Piston-Type Control Booster on an Airfoil and Aileron Model

"Measurements of control moments were made in the NACA stability tunnel to determine the operational characteristics of a piston-type control booster on an aileron. The booster was so constructed and installed that pressures picked up from the air stream below the wing acted on a pair of pistons. The data are presented in the form of curves of pressure coefficients acting on the pistons, hinge-moment coefficients, and booster coefficients plotted against aileron deflection" (p. 1).
Date: November 1943
Creator: Bird, J. D. & Mendelsohn, Robert A.
System: The UNT Digital Library
Tests of a 0.1475c Aileron With a Tab on Low-Drag Section for Curtiss XP-60 Airplane in the Low-Turbulence Tunnel (open access)

Tests of a 0.1475c Aileron With a Tab on Low-Drag Section for Curtiss XP-60 Airplane in the Low-Turbulence Tunnel

"Preliminary two-dimensional tests of the hinge-moment characteristics of a 0.1725c internally balanced aileron on the subject XP-60 wing section indicated that more internal balance would be required if light stick forces were to be obtained at high speeds. The present series of tests were therefore undertaken in order to investigate methods of reducing the slope of the hinge-moment curve while still maintaining the required aileron effectiveness" (p. 1).
Date: November 1941
Creator: von Doenhoff, A. E. & Underwood, W. J.
System: The UNT Digital Library
An Investigation of the Mutual Interference Effects of a Tail-Surface: Stern Propeller Installation on a Model Simulating the Douglas XB-42 Empennage (open access)

An Investigation of the Mutual Interference Effects of a Tail-Surface: Stern Propeller Installation on a Model Simulating the Douglas XB-42 Empennage

Report discussing the mutual interference effects of tail surfaces and a stern propeller on a model of the XB-42.The main focus was to determine the effect of tail surface-propeller spacing upon the periodic tail surface loading coincident with propeller blade passage.
Date: November 9, 1944
Creator: Bartlett, Walter A., Jr. & Marino, Alfred A.
System: The UNT Digital Library
Lift and drag data for 30 pusher-propeller shaft housings on an NACA 65,3-018 airfoil section (open access)

Lift and drag data for 30 pusher-propeller shaft housings on an NACA 65,3-018 airfoil section

Report presenting tests in the two-dimensional low-turbulence pressure tunnel to study the interference effects of various pusher-propeller shaft-housing combinations on a low-drag airfoil. Thirty different combinations were tested, variations being made in shaft size, shape, angle, and fillet.
Date: November 1943
Creator: Abbott, Frank T., Jr.
System: The UNT Digital Library
Effects of Reynolds Number and Leading-Edge Roughness on Lift and Drag Characteristics of the NACA 653-418, a=1.0 Airfoil Section (open access)

Effects of Reynolds Number and Leading-Edge Roughness on Lift and Drag Characteristics of the NACA 653-418, a=1.0 Airfoil Section

Bulletin presenting tests made in the two-dimensional low-turbulence tunnel of an airfoil section with roughness in the form of carborundum grains applied to the leading edge. Marked reductions in maximum lift coefficient were found to be caused by the roughness throughout the test range of Reynolds number.
Date: November 1945
Creator: Quinn, John H., Jr.
System: The UNT Digital Library
Aerodynamic Tests of an NACA 66(215)-116, a=0.6 Airfoil With a 0.25c Slotted Flap for the Fleetwings XA-39 Airplane (open access)

Aerodynamic Tests of an NACA 66(215)-116, a=0.6 Airfoil With a 0.25c Slotted Flap for the Fleetwings XA-39 Airplane

Report presenting testing in the two-dimensional low-turbulence tunnels on a 24-inch-chord model of the NACA 66(215)-116 a = 0.6 airfoil with a 0.25-chord slotted flap. The optimum flap pivot positions were found for three different conditions. The conditions were determined from a consideration of the landing, take-off, and strafing requirements of the airplane.
Date: November 1944
Creator: Cahill, Jones F.
System: The UNT Digital Library
Full-Scale Tunnel Investigation of the Control and Stability of a Twin-Engine Monoplane With Propellers Operating (open access)

Full-Scale Tunnel Investigation of the Control and Stability of a Twin-Engine Monoplane With Propellers Operating

Report presenting extensive force tests covering a wide range of propeller thrust coefficients on a typical twin-engine tractor monoplane model with the horizontal tail surface removed and attached. Measurements were made with flaps retracted and deflected at various angles of attack with different stabilizer and elevator settings. Results regarding the effect of propeller operation on wing-fuselage combination and forces and air flow at tail are provided.
Date: November 1942
Creator: Sweberg, Harold H.
System: The UNT Digital Library
Control-Motion Studies of the PBM-3 Flying Boat in Abrupt Pull-Ups (open access)

Control-Motion Studies of the PBM-3 Flying Boat in Abrupt Pull-Ups

Report presenting a control-motion study in flight that is part of series covering a range of types and sizes of modern airplanes. This particular one involves the PBM-3 flying boat, which is equipped with a control mechanism typical of the cable-type systems in large transport, cargo, or bomber airplanes as well as those employed in flying boats. The elasticity of the elevator control system of the PBM-3 was such to limit the obtainable acceleration to about 3g for center-of-gravity positions in the usual operating range; that is, 26 to 30 percent mean aerodynamic chord, and for the range of airspeeds covered by the tests.
Date: November 1942
Creator: Pearson, Henry A. & Smull, Leland K.
System: The UNT Digital Library
The Theory of Propellers 3: The Slipstream Contraction With Numerical Values for Two-Blade and Four-Blade Propeller (open access)

The Theory of Propellers 3: The Slipstream Contraction With Numerical Values for Two-Blade and Four-Blade Propeller

Report presenting the magnitude of slipstream contraction, which provides information about the conditions of the ultimate wake. Curves and tables are given for the contraction coefficient of two-blade and four-blade propellers for various values of the advance ratio; the contraction coefficient is defined as the contraction in the diameter of the wake helix in terms of the wake diameter at infinity.
Date: November 1944
Creator: Theodorsen, Theodore
System: The UNT Digital Library
The Theory of Propellers 4: Thrust, Energy, and Efficiency Formulas for Single- and Dual-Rotating Propellers With Ideal Circulation Distribution (open access)

The Theory of Propellers 4: Thrust, Energy, and Efficiency Formulas for Single- and Dual-Rotating Propellers With Ideal Circulation Distribution

Report presenting simple and exact expressions for the efficiency of single- and dual-rotating propellers with ideal circulation distribution as given by Goldstein functions for single-rotating propellers and by the new functions for dual-rotating propellers from part I of this series. Efficiency is found to depend primarily on a defined load factor and on an axial loss factor. Tables and graphs are included for practical use of the results.
Date: November 1944
Creator: Theodorsen, Theodore
System: The UNT Digital Library