Characteristics are determined for various modifications of 0.155-chord blunt-nose aileron on semispan model of tapered fighter plane wing. Ailerons with 40 percent nose balance reduced high-speed stick forces. Increased balance chord increases effectiveness and reduces high-speed stick forces. Increased balance chord increases effectiveness and reduces adverse effects of gap at aileron hose. Increase of nose radii increased negative slope of curve hinge-movement coefficient plotted against deflection. Extended deflection range decreased aileron effectiveness for small deflections but increased it at large deflections. Peak pressures at noses of ailerons are relatively high at moderate deflections.

"The measurement of pressure distribution may be accomplished rapidly for any number of locations deemed necessary in model or full-scale investigations by use of the 'belt' method. Reasonable accuracy may be obtained by careful use of this method" (p. 1).

Report presenting an investigation to find a means of obtaining undiluted exhaust-gas samples from a Wright R-2600-B aircraft engine equipped with short individual stacks. Preliminary tests to aid in determining the best design, location, and orientation of orifices ranging in size. Results regarding the Briggs & Stratton engine tests and Wright aircraft engine tests are provided.

Report presenting an analysis of the pressure drop that is required to cool a typically baffled radial engine, which shows that a total pressure drop of 58 pounds per square foot is necessary at sea level and 112 pounds per square foot is required at an altitude of 40,000 feet.

Report presenting an investigation of the effect of wing loading, power loading, and aspect ratio on the performance of pursuit airplanes. The study is based on data combined from specifications, wind-tunnel, and flight tests of various airplanes and presented in graphs.

Report presenting testing of the flutter characteristics of the SB2U-2 airplane. The secondary purpose of the test, which ended up being the primary purpose, was to study the behavior of the airplane just below the flutter speed. Results regarding flutter amplitude, frequencies, and energy-absorbing qualities are provided.

Report presenting general formulas for determining the jet-boundary corrections to the angle of attack, the drag coefficient, the downwash, the pitching, rolling, and yawing-moment coefficients of complete powered yawed models, and to the increments of rolling and yawing-moment coefficients due to the ailerons on yawed models.

Report presenting tests on a scale model of a four-engine cargo airplane, which was tested in the high-speed wind tunnel. The high-speed characteristics of the airplane, particularly the longitudinal stability and control in dives were investigated. Test results indicated that no important changes in longitudinal stability or controllability occurred until the speed exceeded the predicted maximum level-flight speed by more than 38 percent.

Report presenting a series of models of flying-boat hulls tested to determine the effects of the angle of dead rise and the angle of afterbody keel on resistance and spray characteristics. Three angles of dead rise and three angles of afterbody keel were investigated. The results are expressed in nondimensional coefficients.

Report presenting a thermal ice-prevention system for the B-24D airplane. The report includes a description of the design and an outline of the method of design analysis. Results of performance tests of the installation will be presented in a supplementary report.

Report presenting tests in the propeller research tunnel to determine the characteristics at low blade angles of propellers for which high blade angles are already available.

From Summary: "Results are presented of measurement of the pressure drop in ducts produced by two equal 90 degree elbows arranged at three different angular positions to each other, placed adjacent to each other, or separated by straight ducts of various lengths. The measured pressure drops have been analyzed and correlated, and the results are summarized in the form of curves adapted for design computations of pressure drop in compound-duct bends."

Report presenting a method utilizing the Doppler effect on radio signals for determining the speed and distance traveled of an airplane. The method is called the NACA radio ground-speed system and uses the standard radio transmitter already found in most aircraft. Flight tests were made in which the method was used and the results were consisted with calibrated airspeed indications and stop-watch measurements.

Report presenting a detailed account of approximately half of the work planned for a specified contract. The work called for fatigue tests on three simple but basic types of spot-welded test pieces made from 24S-T alclad. The primary purpose of the investigation was determining the mechanism of fatigue failures in the different types of test pieces.