Intercooler cooling-air weight flow and pressure drop for minimum drag loss (open access)

Intercooler cooling-air weight flow and pressure drop for minimum drag loss

Report presenting an analysis of the power losses in airplane flight of cross-flow plate and tubular intercoolers to determine the cooling-air weight flow and pressure drop that give minimum total power loss for any given cooling effectiveness. The investigation covers a range of flight conditions of altitude, airspeed, lift-drag ratio, supercharger-pressure ratio, and adiabatic efficiency.
Date: April 1944
Creator: Reuter, J. George & Valerino, Michael F.
System: The UNT Digital Library
Wind-Tunnel Procedure for Determination of Critical Stability and Control Characteristics of Airplanes (open access)

Wind-Tunnel Procedure for Determination of Critical Stability and Control Characteristics of Airplanes

"This report outlines the flight conditions that are usually critical in determining the design of components of an airplane which affect its stability and control characteristics. The wind-tunnel tests necessary to determine the pertinent data for these conditions are indicated, and the methods of computation used to translate these data into characteristics which define the flying qualities of the airplane are illustrated" (p. 1).
Date: April 1944
Creator: Goett, Harry J.; Jackson, Roy P. & Belsley, Steven E.
System: The UNT Digital Library
Nitrided-steel piston rings for engines of high specific power (open access)

Nitrided-steel piston rings for engines of high specific power

Report presenting testing of several designs of nitrided-steel piston rings under variable conditions of output. Testing indicated the importance of good surface finish and conformity of the ring to the bore. Results regarding temperature tests, single-cylinder-engine tests, and multicylinder-engine tests are provided.
Date: April 1944
Creator: Collins, John H., Jr.; Bisson, Edmond E. & Schmiedlin, Ralph F.
System: The UNT Digital Library
Wind-Tunnel Investigation of Control-Surface Characteristics 16: Pressure Distribution Over an NACA 0009 Airfoil With 0.30-Airfoil-Chord Beveled-Trailing-Edge Flaps (open access)

Wind-Tunnel Investigation of Control-Surface Characteristics 16: Pressure Distribution Over an NACA 0009 Airfoil With 0.30-Airfoil-Chord Beveled-Trailing-Edge Flaps

Report discusses pressure-distribution tests of a plain flap with interchangeable beveled trailing edges on an NACA 0009 airfoil. The flap chord was 30 percent of the airfoil chord and the bevel chords were 15 and 20 percent of the flap chord. The purpose of these tests was to supply pressure-distribution data that may be used for structural and aerodynamic design of horizontal and vertical tail surfaces.
Date: April 1944
Creator: Hoggard, H. Page, Jr. & Bulloch, Marjorie E.
System: The UNT Digital Library
An investigation of aircraft heaters 22: measured and predicted performance of a fluted-type exhaust gas and air heat exchanger (open access)

An investigation of aircraft heaters 22: measured and predicted performance of a fluted-type exhaust gas and air heat exchanger

Report presenting data on the thermal performance and static and total pressure drop characteristics of a fluted-type exhaust gas and air heat exchanger. Results regarding heat transfer, pressure drop, and non-isothermal pressure drop are provided.
Date: April 1945
Creator: Boelter, L. M. K.; Guibert, A. G.; Rademacher, J. M. & Romie, F. E.
System: The UNT Digital Library
An investigation of aircraft heaters 23: measured and predicted performance of a flat-plate type exhaust gas and air heat exchanger (open access)

An investigation of aircraft heaters 23: measured and predicted performance of a flat-plate type exhaust gas and air heat exchanger

Report presenting results of tests of the thermal performance and the static pressure drop characteristics of a flat-plate type exhaust gas and air heat exchanger. The ventilating air shroud built into the heat exchanger gives characteristics of cross flow and parallel flow.
Date: April 1945
Creator: Boelter, L. M. K.; Guibert, A. G.; Rademacher, J. M. & Sanders, V. D.
System: The UNT Digital Library
An Investigation of Aircraft Heaters 25: Use of the Thermopile Radiometer (open access)

An Investigation of Aircraft Heaters 25: Use of the Thermopile Radiometer

Report presenting an analysis of the thermopile radiometer as used in the measurement of irradiation and radiant power interchange is given. The theory of the instrument when used to measure irradiation and net radiant power interchange is developed, and the precautions to be observed when using it for these measurements are presented.
Date: April 1945
Creator: Boelter, L. M. K.; Bromberg, R.; Gier, J. T. & Dempster, E. R.
System: The UNT Digital Library
An Investigation of Aircraft Heaters 21: Measured and Predicted Performance of a Flattened-Tube Type Crossflow Exhaust Gas and Air Heat Exchanger (open access)

An Investigation of Aircraft Heaters 21: Measured and Predicted Performance of a Flattened-Tube Type Crossflow Exhaust Gas and Air Heat Exchanger

Report presenting data on the thermal performance and the static pressure drop characteristics of a flattened-tube type crossflow exhaust gas and air heat exchanger. The measured thermal outputs and static pressure drops are compared with predicted magnitudes.
Date: April 1945
Creator: Boelter, L. M. K.; Guibert, A. G.; Rademacher, J. M.; Romie, F. E.; Sanders, V. D. & Sloggy, L. J. B.
System: The UNT Digital Library
An investigation of aircraft heaters 11: measured and predicted performance of a slotted-fin exhaust gas and air heat exchanger (open access)

An investigation of aircraft heaters 11: measured and predicted performance of a slotted-fin exhaust gas and air heat exchanger

Report presenting the thermal and pressure drop performance data of a slotted-fin Stewart-Warner exhaust gas and ventilating air heat exchanger. Three different crossflow air shrouds were used in testing. The rate of heat transfer was about the same for each shroud, but the static pressure drops varied greatly.
Date: April 1943
Creator: Boelter, L. M. K.; Miller, M. A.; Sharp, W. H. & Morrin, E. H.
System: The UNT Digital Library
An investigation of aircraft heaters 20: measured and predicted performance of a finned-type cast-aluminum crossflow exhaust gas and air heat exchanger (open access)

An investigation of aircraft heaters 20: measured and predicted performance of a finned-type cast-aluminum crossflow exhaust gas and air heat exchanger

Report presenting data on the thermal performance and static pressure drop of a finned-type cast-aluminum exhaust gas and air heat exchanger. Results regarding heat transfer, isothermal pressure drop, and heater surface temperature are provided.
Date: April 1945
Creator: Boelter, L. M. K.; Guibert, A. G.; Rademacher, J. M.; Romie, F. E. & Sanders, V. D.
System: The UNT Digital Library
Wind-Tunnel Investigation of a Rectangular NACA 2212 Airfoil with Semispan Ailerons and with Nonperforated, Balanced Double Split Flaps for Use as Aerodynamic Brakes (open access)

Wind-Tunnel Investigation of a Rectangular NACA 2212 Airfoil with Semispan Ailerons and with Nonperforated, Balanced Double Split Flaps for Use as Aerodynamic Brakes

Flat-plate flaps with no wing cutouts and flaps having Clark Y sections with corresponding cutouts made in wing were tested for various flap deflections, chord-wise locations, and gaps between flaps and airfoil contour. The drag was slightly lower for wing with airfoil section flaps. Satisfactory aileron effectiveness was obtained with flap gap of 20% wing chord and flap-nose location of 80 percent wing chord behind leading edge. Airflow was smooth and buffeting negligible.
Date: April 1945
Creator: Ivey, Margaret F. & Toll, Thomas A.
System: The UNT Digital Library
A method for estimation of maximum stresses around a small rectangular cut-out in a sheet-stringer panel in shear (open access)

A method for estimation of maximum stresses around a small rectangular cut-out in a sheet-stringer panel in shear

"A method for the estimation of the maximum stresses around a small rectangular cut-out in a sheet-stringer panel loaded in pure shear is presented; this method is based on a simplified application of the shear-lag theory. Comparisons indicate that the experimental maximum stringer and shear stresses agree reasonably well with the predictions, provided that neither the length nor the width of the cut-out is greater than the half-width of the panel" (p. 1).
Date: April 1944
Creator: Moggio, Edwin M. & Brilmyer, Harold G.
System: The UNT Digital Library
Investigation of Effect of Sideslip on Lateral Stability Characteristics 2: Rectangular Midwing on Circular Fuselage With Variations in Vertical-Tail Area and Fuselage Length With and Without Horizontal Tail Surface (open access)

Investigation of Effect of Sideslip on Lateral Stability Characteristics 2: Rectangular Midwing on Circular Fuselage With Variations in Vertical-Tail Area and Fuselage Length With and Without Horizontal Tail Surface

Report describing power-off tests in the 6- by 6-foot test section of the stability tunnel to determine the variation of the static lateral stability characteristics with vertical-tail area, fuselage length, and wing dihedral. Two NACA 23012 rectangular wings with rounded tips and dihedral angles of 0 and 5 degrees were tested alone and in combination with three circular fuselages of different lengths. Results regarding the interference effects, effect of horizontal tail, effect of changes in fuselage length, effect of changes in vertical-tail area, effect of changes with constant tail volume, effect of changes in dihedral, and a comparison of data from 7- by 10-foot and stability tunnels are provided.
Date: April 1945
Creator: Hollingworth, Thomas A.
System: The UNT Digital Library
Comparative Cooling of Cylinders of Nonuniform Fin Width With Tight-Fitting Baffles and With Baffles That Provide Constant Flow-Path Areas (open access)

Comparative Cooling of Cylinders of Nonuniform Fin Width With Tight-Fitting Baffles and With Baffles That Provide Constant Flow-Path Areas

Report presenting an investigation using tight-fitting baffles on the cooling fins of several modern air-cooled engine cylinders in order to maintain a constant free-flow area from the front to the rear of each interfin air passage. Results regarding the effect of restriction in cooling-air flow paths on cylinder temperature and effect of restrictions in cooling-air flow paths on cooling-air mass flow are provided.
Date: April 1944
Creator: Schey, Oscar W.; Rollin, Vern G. & Buckner, Howard A., Jr.
System: The UNT Digital Library
Effect of Coaxial Lapping of Cast-Iron Piston Rings on Ring Performance (open access)

Effect of Coaxial Lapping of Cast-Iron Piston Rings on Ring Performance

Report presenting a series of 25-hour accelerated high-output tests run on a single-cylinder aircraft-type spark-ignition engine to determine the effect of coaxial lapping of piston rings prior to engine operation. Standard cast-iron rings were used and tested with all rings lapped and with only the oil-control rings lapped. The results indicated that coaxial lapping with loose abrasive reduced both wear and scuffing.
Date: April 1944
Creator: Shames, Sidney J.; Machlin, Eugene S. & Wilson, John G.
System: The UNT Digital Library
"General" Main-Spray Tests of Flying-Boat Models in the Displacement Range (open access)

"General" Main-Spray Tests of Flying-Boat Models in the Displacement Range

Report presenting a method for showing, by means of three curves, the locations of points of tangency to the envelope of the main-spray blisters generated by flying boat hull models obtained from general testing. Three equations are applied to data from general spray testing on seven models.
Date: April 1945
Creator: Locke, F. W. S., Jr.
System: The UNT Digital Library
A Method for Studying the Longitudinal Dynamic Stability of Flying-Boat-Hull Models at High Planing Speeds and During Landing (open access)

A Method for Studying the Longitudinal Dynamic Stability of Flying-Boat-Hull Models at High Planing Speeds and During Landing

Report presenting an investigation of a method of studying the longitudinal dynamic stability of flying-boat-hull models, as instability may be encountered when flying a flying boat on the water at high speeds and high trim angles, especially upper-limit porpoising and skipping. A method is described for carrying out generalized experimental studies of the longitudinal dynamic stability of flying-boat-hull models.
Date: April 1945
Creator: Locke, F. W. S., Jr. & Hugli, W. C., Jr.
System: The UNT Digital Library
Effect of spring and gravity moments in the control system on the longitudinal stability of the Brewster XSBA-1 airplane (open access)

Effect of spring and gravity moments in the control system on the longitudinal stability of the Brewster XSBA-1 airplane

Report presenting calculations to determine the effects of spring and gravity moments in the control system on the longitudinal-stability characteristics of the Brewster XSBA-1 airplane, and the computed results have been verified by flight tests.
Date: April 1942
Creator: Phillips, William H.
System: The UNT Digital Library
Flight Tests of the Lateral Control Characteristics of an F6F-3 Airplane Equipped with Spring-Tab Ailerons (open access)

Flight Tests of the Lateral Control Characteristics of an F6F-3 Airplane Equipped with Spring-Tab Ailerons

Tests were made to determine whether spring-tab ailerons tended to oscillate or flutter in speed ranges up to 400 mph. Flight tests showed spring-tab ailerons had desirable light stick forces and no tendency to overbalance. No flutter tendencies were indicated up to 400 mph, and any oscillations following abrupt control deflections were heavily damped.
Date: April 1945
Creator: Williams, Walter C.
System: The UNT Digital Library
A Method of Shear-Lag Analysis of Box Beams for Axial Stresses, Shear Stresses, and Shear Center (open access)

A Method of Shear-Lag Analysis of Box Beams for Axial Stresses, Shear Stresses, and Shear Center

Report presenting a practical and relatively rapid method of compensating for shear lag in box-beam analysis with accuracy sufficient for design purposes. Effectiveness curves for box beam elements are derived for an ideal, symmetrical structure. Tabular computation forms for rapid, accurate calculations of axial stresses, shear center, and shear stresses for beam with shear lag are induced.
Date: April 1942
Creator: Erlandsen, Oscar, Jr. & Mead, Lawrence M., Jr.
System: The UNT Digital Library
Numerical Evaluation of the (Epsilon)-Integral Occurring in the Theodorsen Arbitrary Airfoil Potential Theory (open access)

Numerical Evaluation of the (Epsilon)-Integral Occurring in the Theodorsen Arbitrary Airfoil Potential Theory

Report presenting the development of a method of evaluating the epsilon-integral occurring in the arbitrary airfoil theory of Theodorsen by retaining higher order terms in the Taylor expansion and by use of Simpson's rule. Formulas are given for routine calculation of the epsilon-integral and for the necessary computational coefficients.
Date: April 1944
Creator: Naiman, Irven
System: The UNT Digital Library
Flight investigation of the performance and cooling characteristics of a long-nose high-inlet-velocity cowling on the XP-42 airplane (open access)

Flight investigation of the performance and cooling characteristics of a long-nose high-inlet-velocity cowling on the XP-42 airplane

Report presenting the results of a series of flight tests of the maximum speed and cooling characteristics in high-speed level flight and in climb of the XP-42 airplane equipped with a long-nose high-inlet-velocity cowling. The results indicated that a maximum speed of 338 miles per hour at 870 horsepower at 17,000 feet was achievable, which is above the engine critical altitude. Pressure measurements in the entrances in the cylinder baffles showed a uniform distribution of pressure on the front of the engine in high-speed level flight and a fairly uniform distribution in full-power climb.
Date: April 1942
Creator: Bailey, F. J., Jr.; Johnston, J. Ford & Voglewede, T. J.
System: The UNT Digital Library
Free-Flight-Tunnel Investigation of the Effect of the Fuselage Length and the Aspect Ratio and Size of the Vertical Tail on Lateral Stability and Control (open access)

Free-Flight-Tunnel Investigation of the Effect of the Fuselage Length and the Aspect Ratio and Size of the Vertical Tail on Lateral Stability and Control

Report presenting tests in the free-flight tunnel to determine the effect of the fuselage length and the aspect ratio and size of the vertical tail on lateral stability and control. Fuselages of two different lengths and various vertical tail surfaces were used on a powered model in the investigation. Results regarding the test conditions, flight tests, and force tests are provided.
Date: April 1943
Creator: Shortal, Joseph A. & Draper, John W.
System: The UNT Digital Library
Effect of Wing Leading-Edge Slots on the Spin and Recovery Characteristics of Airplanes (open access)

Effect of Wing Leading-Edge Slots on the Spin and Recovery Characteristics of Airplanes

Report presenting an investigation in the NACA 15-foot free-spinning tunnel to determine the effect of wing leading-edge slots on spin and recovery characteristics. The results indicate that recovery will generally be slower with the slots open than with them closed and the spin will be flatter and at a lower rate of descent.
Date: April 1943
Creator: Neihouse, Anshal I. & Pitkin, Marvin
System: The UNT Digital Library