This document contains reproductions of the technical papers presented at the NACA - University Conference on Aerodynamics held at the Langley Aeronautical Laboratory on June 21, 22, and 23, 1948. The conference was held in recognition of the difficulties, imposed by security restrictions, in keeping abreast of the rapid advances in aerodynamics. The papers were prepared to review the status of a number of fields of interest, to summarize the more important wartime advances that are no longer classified, and to orient reference material for further study.

Report discussing the hydrodynamic characteristics of a flying boat with a low-drag, planing-tail hull compared with a conventional-type hull. The planing-tail model had more take-off stability than the conventional model and had lower hydrodynamic resistance. Information about the landing stability, variation of trim with speed, and spray characteristics is also provided.

Report presenting tests at Mach numbers between 1.36 and 2.01 of a twin-scoop air intake enclosing 61.5 percent of the maximum circumference of a body of revolution and located five forebody diameters behind the apex, which showed that the total pressure recovered after diffusion was about 10 percent greater than that attained in previous tests with an annular entrance of the same area.

Report presenting the results of tests on a model of a jet-propelled airplane and a comparison of drag, maximum lift coefficient, and elevator angle required for level flight in the wind tunnel and in flight. Results regarding the aerodynamic characteristics, longitudinal control, wing pressure distribution, and dive-recovery flaps are provided.

Report presenting an investigation of a one-eighth segment of an annular combustor suitable for use as a component of an experimental turbojet engine. Due to the small space available for the combustor, a special design involving a minimum of obstructions in the combustion chamber was created. Results regarding the temperature-rise efficiency, total-pressure loss, and exhaust-gas temperature variation for several simulated engine operating conditions are provided.

Memorandum presenting equations for obtaining the wall coordinates of two-dimensional supersonic nozzles. The equations are based on the application of the method of characteristics to irrotational flow of perfect gases in channels. A brief discussion of characteristics as applied to nozzle design is given to assist in understanding and applying the nozzle-design method of the report.

"A bibliography of NACA papers on rotating-wing aircraft issued up to July 1948 is presented. The list of papers is subdivided for ready reference under appropriate subject headings, and the titles are listed chronologically within each subject" (p. 1).

"The hydrodynamic characteristics of a flying-boat incorporating a low-drag, planing-tail hull were determined from model tests made in Langley tank number 2 and compared with tests of the same flying boat incorporating a conventional-type hull. The planing-tail model, with which stable take-offs were possible for a large range of elevator positions at all center-of-gravity locations tested, had more take-off stability than the conventional model" (p. 1).

The gust and draft velocities from records of NACA instruments installed in P-61C airplanes participating in thunderstorm flights at Clinton County Army Air Field, Ohio, from June 11, 1947 to July 11, 1947 are presented.

Results of wind-tunnel tests of a semispan model of a triangular wing of aspect ratio 2 with a skewed wing-tip flap are presented. Lift, drag, pitching-moment, and hinge-moment data are included for subsonic Mach numbers up to 0.95. The flap showed extremely high hinge moments and low effectiveness as a longitudinal control. Although less affected by compressibility, this flap is indicated to be inferior to a constant-chord flap when applied to this triangular wing.

"An investigation of the rolling effectiveness at transonic and supersonic speeds of a wing-aileron configuration simulating the D-558-2 airplane has been made by means of a rocket-propelled test vehicle. The variation of rolling effectiveness with Mach number is similar to that obtained previously for tapered sweptback wings having full-span, 0.2-chord ailerons" (p. 1).

Report presenting a semispan triangular wing with a constant-chord trailing-edge flap to evaluate the aerodynamic characteristics of the wing with landing speeds up to a Mach number of 0.95. Tests were included to ascertain the effects of the addition of a body and of modifications to the airfoil section. Results regarding the wing alone with low Mach number, wing alone with high Mach number, effect of the body, effect of the flap, effect of Mach number, lift-drag ratio, and wing-profile modifications are provided.

Report presenting testing on parabolic bodies of revolution of two fineness ratios in the transonic and supersonic range. One had a body fineness ratio of 7.87 and one had a ratio of 12 and were tested under different Mach number ranges. Experimental results and drag estimates of various portions of the body are provided.

Report presenting static-pressure measurements made through the speed of sound by the NACA wing-flow method at the back of two unswept circular cylinders and one sweptback cylinder. Static pressures were found to decrease considerably with an increase in Mach number. Information about the length and diameter of the cylinders and how it affects measurements is provided.

Report presenting testing of seven models that from two different wing series: a series of taper ratio 0.5 and differing aspect ratio and a series of aspect ratio 4 and differing taper ratio. Measurements of lift, drag, and pitching moment were made at Mach number 1.53. The aerodynamic parameters generally varied with aspect ratio and taper ratio in the manner indicated by the linear theory.

Report presenting a wind-tunnel investigation at low speed to determine the aerodynamic characteristics of a 51.3 degree sweptback semispan wing with a raked tip and with 16.7-percent-chord sealed plain ailerons. Lift, drag, pitching-moment, and hinge-moment data were obtained for the wing with transition free and fixed with various spans of aileron deflected as lift flaps. The rolling moment, yawing moment, hinge moment, and aileron seal pressure characteristics were determined for each of the nine possible aileron-span and trailing-edge-angle combinations tested.

Wind-tunnel tests of a simplified nacelle on a semispan wing having approximately 35 degrees of sweepback were made at low speeds to evaluate the effects of the nacelle on the aerodynamic characteristics of the wing. Force, moment, and pressure-distribution measurements are presented for the nacelle underslung and centrally mounted on the wing and mounted on a strut below the wing.

Memorandum presenting a review of information relating to aircraft fires to determine what new or further research might lead to a substantial reduction of the aircraft fire hazard in flight and following crashes. An examination of fuels, lubricants, and hydraulic fluids as inflammable liquids is presented, together with possible sources of ignition under the general categories of hot surfaces, electric sparks and arcs, flames, and hot gases.

Report presenting results of an experimental investigation to determine the temperature distribution in an aircraft-engine gas-turbine disk. Calculated stresses based on the measured temperature distributions are presented. Results regarding stresses in the inner region of the disk and stresses in the rim of the disk are provided.

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Price Daniel, regarding a legal question submitted for clarification: Rule-making power of the Labor Commissioner under the Health, Safety, and Morals Act (V.C.S. Art. 1573-80; P.C. Art. 1567-68;) and whether the term "oil and gas fields" as used by the 44th Leg., 1935, R.S. Ch. 245, p. 168, refers to a geographical area or to the oil and gas petroleum industry.

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Price Daniel, regarding a legal question submitted for clarification: The authority of a county court to require surrender of the operator's license, for transmittal to the Department of Public Safety, following conviction of the operator for driving while intoxicated.

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Price Daniel, regarding a legal question submitted for clarification: Applicability of subsection 11g, Section 2, Appropriation bill for current biennium, to members of the State Soil Conservation Board.

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Price Daniel, regarding a legal question submitted for clarification: Legality of member of County School Board contracting with a local school district for the sale of gasoline for repairs for its school busses.

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Price Daniel, regarding a legal question submitted for clarification: Authority of the County Judge or Commissioners' Court to remit a fine paid upon being adjudged guilty of a misdemeanor.