It is argued that there should be an agreement as to what conventions to use in determining absolute coefficients used in aeronautics and in how to plot those coefficients. Of particular importance are the absolute coefficients of lift and drag. The author argues for the use of the German method over the kind in common use in the United States and England, and for the Continental over the usual American and British method of graphically representing the characteristics of an airfoil.

From Introduction: "This report presents the results of these tests which cover a total of about 70 flying hours on this airplane."

"This report presents results of a research and engineering program performed during the first half of 1950 that resulted in an acoustical treatment for the 8- by 6-foot supersonic wind tunnel at the Lewis Flight Propulsion Laboratory" (p. 1).

Report discussing an adapter which uses three Tuckerman optical strain gages to measure the displacement of the three vortices of an equilateral triangle along lines 120 degrees apart. These displacements are substituted in well-known equations in order to compute the magnitude and direction of the principal strains. Tests of the adaptor indicate that principal strains over a gage length of 1.42 inch may be measured with a systematic error not exceeding 4 percent and a mean observational error of the order of + or minus 0.000006. The maximum observed error in strain was of the order of 0.00006. The directions of principal strains for unidirectional stress were measured with the adaptor with an average error of the order of 1 degree.

Report presenting an investigation of the characteristics of partial-span spoilers located at 0.75 of the chord on an NACA 66-series tapered wing, especially at high speeds. The effect of small spoiler projections was found to increase with an increase in speed until the critical Mach number was exceeded.

From Introduction: "The airfoil sections tested, which differ only in thickness ratio, were the NACA 64-006, 64-008, 64-010, and 641-012. Lift, drag, and pitching-moment data were obtained for Mach numbers of 0.3 to that for tunnel choke at angles of attack of -2^o to 31^o. The results of this investigation are reported herein."

Memorandum presenting an investigation of the flow characteristics over a 6-percent-thick symmetrical circular-arc airfoil section with a 30-percent-chord trailing-edge flap at a Mach number of 6.90 and a Reynolds number of 1.65 x 10(sub 6). The model was tested over an angle-of-attack range of 0 to 16 degrees and a flap-deflection range of -16 degrees to 16 degrees. Results regarding pressure results and aerodynamic characteristics are provided.

Report discussing tests to determine the aerodynamic characteristics of a model of a 45 degree swept-wing fighter airplane and to determine the loads on attached stores and detached missiles. An investigation into aileron-spoiler effectiveness, aileron hinge moments, and the effects of wing modifications of aerodynamic characteristics was also carried out at various Mach numbers. Results are presented, but caution is provided in regards to extrapolating results from the model onto a full-scale aircraft.

Memorandum presenting an investigation in the Unitary Plan wind tunnel to determine the aerodynamic characteristics of a model of a 45 degree swept-wing fighter airplane, and to determine the loads on attached stores and detached missiles in the presence of the model. Results also included a determination of aileron-spoiler effectiveness, aileron hinge moments, and the effects of wing modifications on model aerodynamic characteristics. The results are presented with minimum analysis.

Report presenting theoretical pressure distributions and experimental aerodynamic characteristics at low speeds for a group of NACA four-digit series airfoil sections. Results regarding lift, drag, and pitching moment are provided.

From Introduction: "The results of one phase of this investigation, presented in reference 1, have indicated that hull drag can be reduced without causing large changes in aerodynamic stability and hydrodynamic performance by the use of high length-beam ratios. Another phase of the investigation, reference 2, indicated that hulls of the deep-step planning-tail type have much lower air drag than the conventional type of hull and about the same aerodynamic stability; tank tests, reference 3, have indicated that this type of hull also has hydrodynamic performance equal to and in some respects superior to the conventional type of hull. Unpublished tank tests have indicated that the hull models presented in the present paper (with the possible exception of the forebody alone for which data are not available) will have acceptable hydrodynamic performance."

Report discussing an investigation of the effect of sweepback angle on wing-fuselage characteristics at a subsonic and a supersonic Mach number. Lift, drag, and pitching-moment coefficients, downwash-angle, and total-pressure measurements are all provided.

"An investigation has been made in the Langley 4-by-4-foot supersonic pressure tunnel to determine the aerodynamic characteristics of a series of missile configurations having low-aspect-ratio wings at a Mach number of 2.01. The effects of wing plan form and size, length-diameter ratio, forebody and afterbody length, boattailed and flared afterbodies, and component force and moment data are presented for combined angles of attack and sideslip to about 28 degrees. No analysis of the data was made in this report" (p. 1).

Report presenting an investigation at Mach numbers of 1.61 and 2.01 to determine the control effectiveness and hinge-moment characteristics for a series of 25.4-percent-chord trailing-edge controls on a trapezoidal wing with a 23 degree sweptback leading edge, aspect ratio of 3.1, and taper ratio of 0.4. Pressure distribution and hinge-moment measurements were made at a range of angles of attack and control deflections. Results regarding effect of control deflection, effect of wing angle of attack, effect of Reynolds number, effect of trailing-edge thickness, effect of hinge-line gap, effect of Mach number, and effect of control size and location are provided.

Report presenting an investigation in the supersonic pressure tunnel at two Mach numbers to determine the aerodynamic characteristics of several jet-spoiler controls on a wing having a 45 degree sweepback of the quarter-chord line, an aspect ratio of 3.5, a taper ratio of 0.3, and an NACA 65A005 airfoil section. Testing indicated that the jet-spoiler effectiveness increased with increasing angle of attack and correlated well with the momentum of jet flow.

Report presenting testing of a series of three wings over a range of Mach numbers by the use of the transonic-bump technique. The lift, drag, pitching-moment, and root-bending-moment data of wings of a variety of aspect ratios but with the same quarter-chord lines and airfoil sections were obtained.

From Introduction: "Recent investigations have indicated several wing plan forms, wing sections, and wing-body-tail combinations suitable for flight at supersonic speeds. One such lifting surface, a thin, sharp-edged without sweep of aspect ratio 4 and taper ratio 0.5, has been the subject of an investigation in the Ames 12-foot pressure wind tunnel. The aim of the investigation was to determine the aerodynamic characteristics of such a wing plan form throughout the range of subsonic Mach numbers up to 0.94."

From Introduction: "A method for the design of three-dimensional nozzles based on axi-symmetric flow is presented in this paper. The design method presented in this paper is general; however, as an illustrative example of the design of a Mach number 10 nozzle with square test section is included."

Report presenting testing of a modified 1/10-power nose shape in free flight at Mach numbers up to 6.7. Measured heating rates were presented and compared with calculated values. Results regarding transition and comparison with previous investigations are provided.

Report presenting an investigation of the aerodynamic characteristics of a four-blade rigid model propeller in the full-scale tunnel for a range of angles of attack, blade angles, and advance ratio. It included a preliminary explanation of vertical descent and a comparison with theory. Results regarding the static thrust and forward flight are provided.

This report presents a description of the design of the Cuatro Vientes wind tunnel.

From Summary: "The present report presents the chordwise distributions of pressure measured concurrently with the force and moment data of NACA TN 3007."

From Introduction: "Although the aerodynamic characteristics of the components of such configurations may be well known, the mutual interference resulting from combining the wings, as well as the wings and body, may be so great that is desirable to study the aerodynamic properties of the complete configurations. Two methods of handling this problem are presented in this report. The first method is essentially an extension of the theory for slender wing-body combinations of reference 1 to determine the load distribution, forces, and moments exerted on slender cruciform-wing and body combinations inclined simultaneously at small angles in pitch and yaw. "

From Introduction: "The tests described in this report are the first in an investigation by N.A.C.A. of the aerodynamic characteristics of possible tailless arrangements. The investigations will be extended to include whatever range is through most desirable and may include, among other things, variations in aspect ratio, taper, sweepback, washout, air-foil section, dihedral, and also control flaps or other control devices of different forms and proportions."