Memorandum presenting a flight investigation in natural icing conditions to determine the effect of ice formations on the performance of an axial-flow turbojet engine. Tail-pipe temperature increased from 761 to 1065 degrees Fahrenheit and the jet thrust decreased from 1234 to 910 pounds during a period of 45 minutes in icing. No general conclusions can be reached from the data because the icing condition was relatively light.

Report presenting an investigation of a model of the Kingfisher XAUM-2 flying torpedo to determine the pressure recoveries within the jet engine nacelle and to determine the effects of several changes in model configuration on the aerodynamic characteristics of the model. The effectiveness of elevons and tabs as control devices was also investigated.

From Introduction: "A 12-percent-chord-thick wedge section and a reversed NACA 0012 section were chosen for these tests as they are representative of sections having no boat tailing and appreciable boat tailing (i.e., blunt and rounded trailing edges, respectively), and the results of this investigation are compared with those obtained from a previous investigation of the NACA 0012 section. Conclusions are drawn regarding the relative merits of the two unconventional sections and the conventional section in transonic speed range."

"A fuel-distribution control for continuous-flow manifold injection on reciprocating engines is described. A method is installation of the control on an engine is suggested. The device controlled the flow to four spring-loaded nozzles within 2 percent of perfect distribution over a wide range of fuel-flow rates and the distribution was practically unaffected by uneven discharge-nozzle pressures" (p. 1).

Report presenting results of chordwise pressure-distribution measurements on a 45 degree sweptback wing at transonic speeds. The two stations for measuring were located at the 18 percent chord from the root and the 87 percent chord. The changes in pressure distribution with Mach number did not indicate any appreciable net loss in section lift, but did indicate large increases in the section drag and diving moment.

"It is shown that for velocities slightly in excess of sonic, the position of detached shock wave located in front of a given body at zero angle of attack may be estimated theoretically to a reasonable degree of accuracy. In case of bodies of revolution the result was simple, but for two-dimensional bodies, pressure coefficient varies with Mach number, and slight difficulty appears. Theory developed compares favorably with available experimental data" (p. 1).

Report presenting an investigation of the performance of a turbojet engine equipped with a tail-pipe burner at zero ram over a range of rotor speeds and tail-pipe-burner fuel flows. A thrust augmentation of 40 percent was obtained at zero ram for a tail-pipe-burner fuel-air ratio of 0.043 or a total fuel-air ratio of 0.056. Results with an engine with standard tail pipe, engine with tail pipe burner and no afterburning, and engine with tail pipe burner and afterburning are provided.

Report presenting airspeed and altitude data for nonscheduled cargo operations of a Douglas DC-4 airplane between Seattle, Washington and Alaska during February and March of 1947 to determine the probability of reaching or exceeding given values of airspeed and Mach number. The total probability of exceeding a placard never-exceed speed of 266 mph depends primarily on exceeding the speed in descent. The probability was found to be about once in 100 hours of descent or once in 1000 hours of general flying time.

Report presenting testing of six flutter wings, two swept 45 degrees and four unswept, attached to three freely falling bodies. Flutter frequency and phasing were recorded.

Report presenting flight tests to determine the longitudinal stability and control characteristics of models of the Lark pilotless aircraft. Testing included the standard configuration with the horizontal wing flaps deflected 0 degrees, 15 degrees, and 60 degrees, and a test with the tail surfaces in line with the wings with the wing flaps not deflected. Results regarding time-history records, drag, longitudinal stability, and control effectiveness are provided.

Memorandum presenting an analysis of selected experimental pressure-distribution data at transonic speeds for the purpose of deriving an empirical method which may be used for estimating the trailing-edge loads and bending moments at the design stage. The trailing-edge normal-force and bending-moment coefficients calculated by the derived method follow the general trend of the experimental data and appear to be a guide where specifically applicable chordwise pressure-distribution data at transonic speeds are not available.

From Introduction: "This paper presents the results of the investigation of the wing-alone and wing-fuelage configurations employing a wing with the quarter-chord line swept back 60^o, aspect ratio 4, taper ratio 0.6, and an NACA 65A006 airfoil section parallel to the free stream."

Report presenting an investigation of two sharp-edge annular inlets with conical central bodies at low airspeeds in the propeller research tunnel to obtain information concerning the surface-pressure, drag, and pressure-recovery characteristics of the inlets at subsonic flight. Results regarding the nose and inner surface of the diffuser, inlet lips, minimum surface pressures and critical Mach numbers, pressure surveys in inlets, and pressure surveys in diffusers are provided.

Report presenting measurements made at transonic speeds by the freely-falling-body method to compare the drag of a rectangular plan-form airfoil of aspect ratio 7.6 with an NACA 65-006 airfoil section. Results regarding the velocity measurements, base-pressure measurements, and airfoil drag measurements are provided.

"Pressure-distribution data of the NACA 64(sub 1)-012 and 64(sub 1)A012 airfoils have been analyzed to determine the effects of increasing the trailing-edge angle from 9 to 14 degrees. The primary effect of increasing the trailing-edge angle was to decrease the loading over the rear portion of the airfoil under lifting conditions. The differences in trailing-edge load increased with Mach number and lift coefficient" (p. 1).

Report presenting a method for the preparation and purification of the intermetallic molybdenum desilicide was developed and its properties were determined. Chemical properties were found to be highly inert, unattacked by boiling hydrochloric acid, sulfuric acid, or aqueous sodium hydroxide, slightly attacked by nitric acid, and dissolved by molten sodium hydroxide. Other mechanical properties of the material were also provided.

Report discussing an investigation of two full-scale NACA propellers at a range of blade angles and at speeds of up to 500 miles per hour. The results are compared to previous investigations of five NACA propellers to evaluate the effects of blade-section thickness ratios on propeller characteristics.

Report presenting a two-dimensional wind-tunnel investigation of a 6-percent-thick symmetrical circular-arc airfoil with leading-edge and trailing-edge high-lift devices. The purpose of the investigation was to determine the effects on maximum section lift coefficient of different leading-edge slats and drooped-nose flaps when used in combination with a plain trailing-edge flap. Results regarding slat configuration, drooped-nose-flap configurations, and a comparison of slat and drooped-nose-flap configurations are provided.

Testing was performed at Mach number 1.53 with a wing-fuselage combination with a wing with 63 degrees leading-edge sweep, an aspect ratio of 3.46, and a taper ratio of 0.25. The wing had an NACA 64A005 thickness distribution parallel to the plane of symmetry and was cambered and twisted. Results regarding the comparison of lift, drag, and pitching-moment characteristics of WF-63c and WF-63, effects of sweep, and effects of Reynolds number are provided.

Report presenting the results of an experimental investigation of the downwash and wake characteristics behind a triangular plan-form wing in a supersonic stream. Measurements were made of the variation of downwash angle with angle of attack at several positions within the induced flow field. Results regarding the spanwise variation of the induced stream angle, rate of change of downwash at zero lift, variation of downwash with angle of attack, and wake are provided.

From Summary: "The performance of the turbine component of a J33 turbojet engine was determined over a range of turbine speeds from 8000 to 11,500 rpm.Turbine-inlet temperature was varied from the minimum required to drive the compressor to a maximum of approximately 2000 degrees R at each of several intermediate turbine speeds. Data are presented that show the horsepower developed by the turbine per pound of gas flow."

From Summary: "Additional tests of a 1/7-size model of the Grumman XJR2F-1 amphibian were made in Langley tank no. 1 to compare the behavior during take-off of the model equipped with split- and slotted-type flaps. The slotted flag had a large effect on locating the forward center-of-gravity limits for stable take-offs. Stable take-offs within the normal operating range of positions of the center of gravity could be made with the split flaps deflected 45 degrees or with the slotted flaps deflected less than 20 degrees."

"Three modifications of the auxiliary-stage supercharger for the V-1710-93 engine were designed and tested as part of an investigation to improve the power output and the altitude performance of the engine. A 12-vane diffuser was substituted for the standard 11-vane diffuser, and a vaneless discharge passage and a modified scroll were designed to increase the flow capacity of the supercharger and thereby to increase the performance at the high volume flows required by the engine. With the 12-vane diffuser installed and the carburetor replaced by an adapter, the equivalent volume flow at the peak efficiency point was increased 25 percent at the lowest speed investigated and 9.5 percent at the highest speed" (p. 1).

"A Douglas C-74 airplane, during a test dive at about 0.525 Mach number, experienced uncontrollable longitudinal oscillations sufficient to cause shedding of the outer wing panels and the subsequent crash of the airplane. Tests of a section of the horizontal tail plane from a C-74 airplane were conducted in the Ames 16-foot high-speed wind tunnel to investigate the possibility of the tail as a contributing factor to the accident. The results of the investigations of fabric-covered elevators in various conditions of surface deformation are presented in this report" (p. 1).