"This document contains reproductions of technical papers on some of the most recent research results on aircraft loads, flutter, and structures from the NACA laboratories. These papers were presented by members of the staff of the NACA laboratories at the Conference held at the Langley Aeronautical Laboratory March 5, 6, and 7, 1957. The primary purpose of this Conference was to convey to contractors of the military services and others concerned with the design of aircraft these recent research results and to provide those attending an opportunity to discuss the results" (p. 6).

Memorandum presenting a wind-tunnel investigation of a high-wing airplane with an aspect ratio 6.75 wing with approximately 36 degrees of sweepback in order to determine the lift effectiveness obtainable with trailing-edge blowing flaps in combination with leading-edge slats. Close to theoretical flap effectiveness was obtained with blowing flaps deflected 45, 55, and 65 degrees at low angles of attack. Results regarding the wind tunnel, take-off performance, landing performance, and comparisons with flight data are provided.

"Flutter models of the upper and lower vertical tails of an air-to-ground missile have been tested in the Mach number range from 0.5 to 3.0. It was found that the upper surface exhibited more or less conventional flutter behavior throughout the Mach number range, whereas the lower surface experienced a sudden change in flutter mode at a Mach number of about 1.18. This change in flutter mode was accompanied by a decrease of about 50 percent in the density required for flutter to occur" (p. 1).

Report presenting an investigation of a reduced-chord multistage turbine at design speed and various turbine-inlet pressures from 12 to 40 inches of mercury absolute. At each inlet pressure, the turbine was operated over a range of overall turbine total-pressure ratios; turbine-inlet temperature was maintained at 700 degrees R. The results indicated that no appreciable effect on turbine overall performance was observed over the range of turbine-inlet total pressures investigated.

Report presenting a study of the first stage performance characteristics of the two-stage turbine from the J73 turbojet engine. The reduced-chord first-stage turbine operated at a peak brake internal efficiency of over 91 percent at a stage overall pressure ratio of 1.4 and at 90 percent of the design equivalent speed. The unit exhibited high efficiency over a wide range of operating variables.

A variational theorem is presented for a body undergoing creep. Solutions to problems of the creep behavior of plates, columns, beams, and shells can be obtained by means of the direct methods of the calculus of variations in conjunction with the stated theorem. The application of the theorem is illustrated for plates and columns by the solution of two sample problems.

Theoretical studies of the turbojet and ramjet combustion process are summarized and the resulting equations are applied to experimental data obtained from various combustor tests. The theoretical treatment assumes that one step in the over-all chain of processes which constitute jet-engine combustion is sufficiently slow to be the rate-controlling step that determines combustion efficiency.

Report discussing an investigation of a 45 degree swept-back-wing-body combination with flap spoiler ailerons, deflector ailerons, and a spoiler-slot-deflector aileron. The pressures were measured from Mach numbers 0.60 to 1.03 and at various angles of attack.

Memorandum presenting a flight investigation to determine the longitudinal and lateral handling qualities of the Douglas X-3 research airplane in the clean configuration. Static and dynamic stability and control characteristics were determined during trimmed and maneuvering flight at an average altitude of 30,000 feet and over a Mach number range from 0.7 to 1.16.

Report presenting a wind-tunnel investigation of a high-wing airplane with an aspect ratio 6.75 wing with approximately 36 degrees of sweepback to determine the lift effectiveness obtainable with trailing-edge blowing flaps in combination with leading-edge slats. Flap effectiveness and stability were maintained to high angles of attack by control of leading-edge flow separation with slats. An analysis of the take-off performance, landing performance, and comparisons with flight data are provided.

Report presenting an investigation of the transonic flutter characteristics of a cantilevered, aspect-ratio-4, 45 degree sweptback, untapered wing with three different pylon-mounted external-store configurations. An additional study was created during the investigation to find a store configuration with a substantially higher flutter speed than what was obtained with the other two stores. Results regarding general comments, the investigation of store types A and B, node-line survey, and the investigation of store type C are provided.

Memorandum presenting a study of two bluff modifications of the TX-28 store in the 27- by 27-inch preflight jet of the Langley Pilotless Aircraft Research Station. Successful releases were made with both stores at near-sea-level conditions with high ejection velocities. Results regarding the Bluff TX-28 and Turnabout TX-28 are provided.

Report presenting an investigation conducted at the 16-foot transonic tunnel to determine the loading characteristics of flap-type ailerons located at inboard, midspan, and outboard positions on a 45 degree sweptback-wing-body combination. Results indicated that the loading over the ailerons was established by the wing-flow characteristics and the loading shapes were irregular in the transonic speed range.

Memorandum presenting an investigation of the use of low auxiliary horizontal-tail surfaces to alleviate the pitch-up tendency at high lift of an airplane configuration with a T-tail. The basic model had a wing with an aspect ratio of 3, a taper ratio of 0.143, and an unswept 80-percent chord line.

Report presenting an investigation in the high speed 7- by 10-foot tunnel through a range of Mach numbers to determine the lateral-control and hinge-moment characteristics of a spoiler-slot-deflector configuration on a semispan 35 degree sweptback-wing model. The results indicated that the spoiler-slot-deflector configuration with the ratio of deflector projection to spoiler projection increasing with increasing control projection has good rolling-moment effectiveness throughout the angle of attack range and throughout the high subsonic speed range.

Memorandum presenting an investigation to determine the static longitudinal and lateral stability of three variations of a flared-skirt-type two-stage missile configuration with three different nose shapes, body cross sections, and skin geometry in the 11-inch hypersonic tunnel. The results of the investigation show that the models with rounded triangular cross sections have a variation of lift, drag, lift-drag ratio, and stability with roll angle.