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Analysis of factors affecting net lift increment attainable with trailing-edge split flaps on tailless airplanes

Description: From Introduction: "The lift increments of different flap arrangements were determined by the method of reference 1 with a simple chord correction factor being applied. This procedure is somewhat similar in basic principles to the method of reference 2. The accuracy of the present method was determined by calculating by means of this method the lift and moment increments of flaps on 10 different finite wing-flap combinations for which wind-tunnel data were available."
Date: September 1944
Creator: Maggin, Bernard
Partner: UNT Libraries Government Documents Department

The Effect of Mass Distribution on the Lateral Stability and Control Characteristics of an Airplane as Determined by Tests of a Model in the Free-Flight Tunnel

Description: The effects of mass distribution on lateral stability and control characteristics of an airplane have been determined by flight tests of a model in the NACA free-flight tunnel. In the investigation, the rolling and yawing movements of inertia were increased from normal values to values up to five times normal. For each moment-of-inertia condition, combinations of dihedral and vertical-tail area representing a variety of airplane configurations were tested. The results of the flight tests of the model were correlated with calculated stability and control characteristics and, in general, good agreement was obtained. The tests showed the following effects of increased rolling and yawing moments of inertia: no appreciable change in spiral stability; reductions in oscillatory stability that were serious at high values of dihedral; a reduction in the sensitivity of the model to gust disturbances; and a reduction in rolling acceleration provided by the ailerons, which caused a marked increase in time to reach a given angle of bank. The general flight behavior of the model became worse with increasing moments of inertia but, with combinations of small effective dihedral and large vertical-tail area, satisfactory flight characteristics were obtained at all moment-of-inertia conditions.
Date: August 1943
Creator: Campbell, John P. & Seacord, Charles L., Jr.
Partner: UNT Libraries Government Documents Department

The significance of the time concept in engine detonation

Description: Report presenting an experimental technique developed by means of which the variables affecting the time element in the detonation process in a spark-ignition engine can be controlled and approximately measured. Results indicated that higher maximum permissible pressures can be used if the rate of compression of the end gas is increased. Suggestions for future study are provided.
Date: January 1943
Creator: Leary, W. A. & Taylor, E. S.
Partner: UNT Libraries Government Documents Department

Experimental determination of the effect of negative dihedral on lateral stability and control characteristics at high lift coefficients

Description: Report presenting the effects of negative dihedral on lateral stability and control characteristics at high lift coefficients determined by flight tests with a model. As the effective dihedral was decreased, the model became increasingly difficult to fly. Results regarding the effect of directional stability and lift coefficient on flight behavior are also provided.
Date: January 1946
Creator: McKinney, Marion O., Jr.
Partner: UNT Libraries Government Documents Department

An Experimental Investigation of Flow Across Tube Banks

Description: Flow across tube banks was investigated by surveys of total dynamic and static pressure by visualization of the flow through the use of titanium tetrachloride smoke, by thermocouple surveys of heated tubes, and by hot-wire surveys of both heated and unheated tubes. It was found that turbulence increased as the depth of the bank increased and that the broad wake behind each tube affected flow over the succeeding tubes.
Date: March 1942
Creator: Brevoort, M. J. & Tifford, A. N.
Partner: UNT Libraries Government Documents Department

An Experimental Investigation of the Effect of Propellers Used as Aerodynamic Brakes on Stability and Control

Description: Tests were made of a model representative of a single-engine tractor-type airplane for the purpose of determining the stability and control effects of a propeller used as an aerodynamic brake. The tests were made with single-and dual-rotation propellers to show the effect of type of propeller rotation, and with positive thrust to provide basic data with which to compare the effects of negative thrust. Four configurations of the model were used to give the effects of tilting the propeller thrust axis down 5 deg., raising the horizontal tail, and combining both tilt and raised tail. Results of the tests are reported herein. The effects of negative thrust were found to be significant. The longitudinal stability was increased because of the loss of wing lift and increase of the angle of attack of the tail. Directional stability and both longitudinal and directional control were decreased because of the reduced velocity at the tail. These effects are moderate for moderate braking but become pronounced with full-power braking, particularly at high values of lift coefficient. The effects of model configuration changes were small when compared with the over-all effects of negative-thrust operation; however, improved stability and control characteristics were exhibited by the model with the tilted thrust axis. Raising the horizontal tail improved the longitudinal characteristics, but was detrimental to directional characteristics. The use of dual-rotation propeller reduced the directional trim charges resulting from the braking operation. A prototype airplane was assumed and handling qualities were computed and analyzed for normal (positive thrust) and braking operation with full and partial power. The results of these analyses are presented for the longitudinal characteristics in steady and accelerated flight, and for the directional characteristics in high- and low-speed flight. It was found that by limiting the power output of the engine (assuming the constant-speed propeller ...
Date: July 1, 1945
Creator: Hanson, Frederick H
Partner: UNT Libraries Government Documents Department

Test-stand investigation of cooling characteristics and factors affecting temperature distribution of a double-row aircraft engine

Description: Report presenting testing of a double-row radial air-cooled engine to investigate overall cooling characteristics and to analyze what variations in temperature distribution were caused by variations in cooling-air pressure drop, power, and fuel-air ratio. Testing occurred over a range of engine powers.
Date: March 1946
Creator: Sipko, Michael A.; Hickel, Robert O. & Jones, Robert J.
Partner: UNT Libraries Government Documents Department

Tests and approximate analysis of bending stresses due to torsion in a D-section box

Description: From Summary: "Strain surveys were made on the stringers reinforcing a D-section box loaded in torsion and restrained from warping at the root. On the basis of the tests, a procedure is suggested for estimating the bending stresses due to torsion that occur near the flange of a D-section box. A similar test of a triangular-section box showed that for such a section there were no significant bending stresses due to torsion, a fact which was also shown theoretically."
Date: May 1944
Creator: Duberg, John E. & Brilmyer, Harold G.
Partner: UNT Libraries Government Documents Department

The problem of thermal-expansion stresses in reinforced plastics

Description: Report presenting an analysis of the failure of adhesive bonds and its relation to boundary stress concentrations. A variety of material combinations, including metals and plastics, were examined and stress tested. The method of computing the thermal coefficients is applied to mixtures and especially to reinforced plastics.
Date: June 1942
Creator: Turner, P. S.
Partner: UNT Libraries Government Documents Department

Some systematic model experiments on the porpoising characteristics of flying-boat hulls

Description: From Summary: "This report presents the results of systematic model experiments on the hydrodynamic characteristics of flying boats, aimed primarily at developing a comprehensive view of the factors influencing porpoising and of their relative importance. The experiments 'radiated' from a given reference ship; they embrace changes, over reasonably wide ranges, in the value of each of a number of variables, treated independently. The experimental results are summarized in a series of 25 figures, each of which gives the complete data for all the modifications of one variable."
Date: June 1943
Creator: Davidson, Kenneth S. M. & Locke, F. W. S., Jr.
Partner: UNT Libraries Government Documents Department

Statistical Analysis of the Characteristics of Repeated Gusts in Turbulent Air

Description: Statistical methods were applied to acceleration and airspeed data obtained with the XC-35 airplane during flights in turbulent air within convective clouds in order to determine the characteristics of repeated or closely spaced gusts pertinent to design problems. Results indicated that, in turbulent air within convective cloud, gusts tend to be contiguous and are seldom found isolated in space. Over-all average spacing between repeated gusts was in good agreement with twice the average gust-gradient distance of 10 chords used in present design.
Date: November 1945
Creator: Moskovitz, A. I. & Peiser, A. M.
Partner: UNT Libraries Government Documents Department

Static-thrust tests of six rotor-blade designs on a helicopter in the Langley full-scale tunnel

Description: Report discusses the results of testing of measurements of the static-thrust performance of six sets of rotor blades mounted on a helicopter fuselage. The blades differed in surface condition, pitch distribution, airfoil section, plan form, and solidarity. Results indicated that rotor-blade surface condition is important for performance and the optimum performance will only be obtained if the blades have a smooth, accurately contoured surface that will not deform during flight.
Date: September 1945
Creator: Dingeldein, Richard C. & Schaefer, Raymond F.
Partner: UNT Libraries Government Documents Department

Summary report on the induction of water to the inlet air as a means of internal cooling in aircraft-engine cylinders

Description: Report presenting investigations of a full-scale air-cooled aircraft-engine cylinder of 202-cubic-inch displacement to determine the effects of internal cooling by water induction on the maximum permissible power and output of an internal-combustion engine. Results regarding the maximum permissible engine performance, engine temperatures, and constant inlet-air pressure investigations are provided.
Date: August 15, 1942
Creator: Rothrock, Addison M. & Jones, Anthony W.
Partner: UNT Libraries Government Documents Department

Progress report on strength and creep of special ceramic bodies in tension at elevated temperatures

Description: Report presenting an investigation for the determination of the behavior of ceramic bodies in tension at elevated temperatures for the purpose of determining data for the design of ceramic blades for gas turbines. Observations were made of six special ceramic bodies in order to determine their tensile strength and creep during prolonged loading under a range of stresses and temperatures.
Date: June 1946
Creator: Geller, R. F. & Burdick, M. D.
Partner: UNT Libraries Government Documents Department

The resistance of three series of flying boat-hulls as affected by length-beam ratio

Description: Report presents correlation of data obtained from several independent length-beam-ratio investigations to determine the general effect of length-beam ratio on the resistance characteristics of three series of flying-boat hulls. An optimum length-beam ratio was found beyond which no further reduction in hydrodynamic resistance occurred. The optimum ratio depended on the hull lines of any given mode series.
Date: October 1945
Creator: Land, Norman S.; Bidwell, Jerold M. & Goldenbaum, David M.
Partner: UNT Libraries Government Documents Department

Significance of alkylate-replacement values of aviation fuel components

Description: Report discusses the significance of alkylate-replacement values and to illustrate methods of estimating these values. Equations expressing alkylate-replacement values and the estimated effect on engine performance resulting from replacement of alkylate is discussed and test data is provided in F-3 and F-4 laboratory engines. The researchers found that "alkylate-replacement value depends not only upon the rating of the fuel component that is replacing the alkylate but also upon the ratings of the alkylate and the base fuel."
Date: December 1944
Creator: Sanders, Newell D.
Partner: UNT Libraries Government Documents Department

Shear-lag tests of two box beams with corrugated covers loaded to failure

Description: From Summary: "Strain measurements were made on the compression side of two box beams with corrugated aluminum-alloy covers loaded to failure. Angles formed from sheet were used for corner flanges in beam 1; whereas extruded angles were used in beam 2. Failure in each beam occurred in the corner angle at a stress that was above the compressive yield stress for the material."
Date: January 1944
Creator: Chiarito, Patrick T.
Partner: UNT Libraries Government Documents Department

Single-cylinder engine tests of porous chrome-plated cylinder barrels with special bore coatings for radial air-cooled engines

Description: Report discussing a series of single-cylinder engine tests to determine the effect of special surface coatings in porous chrome-plated cylinder barrels on oil consumption and ring wear. The coating materials were selected for their bearing and lubrication properties and on their applicability to processing. The surface coatings tested were lead overplates, silver overplates, and colloidal graphite base paint.
Date: January 1946
Creator: Johnson, Robert L. & Anderson, Roy I.
Partner: UNT Libraries Government Documents Department

Standard method of graphical presentation of centrifugal compressor performance

Description: Report on the NACA recommended method for comparing the performance of centrifugal compressors. The most important indices of compressor performance are the adiabatic temperature rise ratio or adiabatic efficiency, the adiabatic shaft efficiency, and the pressure ratio, which incorporate many other parameters. Recommendations for reporting on compressor effectiveness and characteristics are provided.
Date: August 1945
Creator: NACA Subcommittee on Supercharger Compressors
Partner: UNT Libraries Government Documents Department

Standard procedures for rating and testing centrifugal compressors

Description: Report on the NACA test-rig installation, measurements, instrumentation, test procedure, methods of calculation, and presentation of data for rating and testing centrifugal superchargers. Special precautions for certain portions of testing are also provided.
Date: August 1945
Creator: NACA Subcommittee on Supercharger Compressors
Partner: UNT Libraries Government Documents Department

Some systematic model experiments of the bow-spray characteristics of flying-boat hulls operating at low speeds in waves

Description: Report discusses the results of testing on several models of flying boats, the XPB2M-1, the XPBB-1, the JRM-1, and 11 other models to determine the effect of bow form on the amount of spray thrown onto the windshield of a flying boat in rough water. Several recommendations for reducing the height and volume of spray are provided. Any change in the hull form that softens the impact between the hull and waves seems to reduce the spray.
Date: December 1943
Creator: Locke, F. W. S., Jr.
Partner: UNT Libraries Government Documents Department

Some yawing tests of a 1/30-scale model of the hull of the XPB2M-1 flying boat

Description: Report discusses the results of yawing tests on a model of the complete hull of the XPB2M-1. The tests indicated that there was a tendency toward directional instability in the vicinity of the hump. The researchers concluded that at a certain range, the curves of yawing moment are discontinuous, and this has led to difficulty in preliminary test flights.
Date: July 1943
Creator: Locke, F. W. S., Jr.
Partner: UNT Libraries Government Documents Department

Relation of preignition and knock to allowable engine temperatures

Description: From Summary: "The results are given of an investigation of some of the limitations that now prevent increases in the temperature level of engine cylinder heads, and a review of previous work in the field is included to supplement these results. Attention was given, in particular, to the effects of fuel knock and surface ignition on cylinder temperatures and the effects of cylinder temperatures on performance. Data were obtained from a Wright C9GC air-cooled cylinder and from a Lycoming O-1230 liquid-cooled cylinder."
Date: July 1943
Creator: Biermann, Arnold E. & Corrington, Lester C.
Partner: UNT Libraries Government Documents Department