From Summary: "An analysis of available theory on seaplane impact and a proposed modification thereto are presented. In previous methods the overall momentum of the float and virtual mass has been assumed to remain constant during the impact but the present analysis shows that this assumption is rigorously correct only when the resultant velocity of the float is normal to the keel."
Empirical methods of Ainley and Kochendorfer and Nettles were used to predict performances of nine turbine designs. Measured and predicted performances were compared. Appropriate values of blade-loss parameter were determined for the method of Kochendorfer and Nettles. The measured design-point efficiencies were lower than predicted by as much as 0.09 (Ainley and 0.07 (Kochendorfer and Nettles).
The cooling of a single-row radial air-cooled engine using several cowling arrangements has been studied in the NACA 20-foot wind tunnel. The results show the effect of the propeller and several cowling arrangements on cooling for various values of the indicated horsepower in the climb condition. A table giving comparative performance of the various cowling arrangements is presented. The dependence of temperature on indicated horsepower and pressure drop across the baffles is shown by charts. Other charts show the limiting indicated horsepower against the pressure drop across the engine and the heat dissipated at various values of the indicated horsepower.
The engines, each with a compressor overall total-pressure ratio of 12 and a design inner-turbine-inlet temperature of 2500 degrees R, were investigated at static sea-level conditions to determine the effect on transient performance of varying the desitn pressure ratio divisions 2-6, 3-4, and 4-3 between the outer and inner compressors. The transient considered was an acceleration from 40 to 100 percent design thrust. When the outer compressor of each engine reached design speed, the inner compressors were overspeeding, the maximum being only 1.7 over design mechanical speed. Acceleration times for the three engines were equal.
"Flame speeds based on the outer edge of the shadow cast by the laminar Bunsen cone were determined as functions of composition for methane-air mixtures at initial mixture temperatures ranging from -132 degrees to 342 degrees c and for propane-air and ethylene-air mixtures at initial mixture temperatures ranging from -73 degrees to 344 degrees c. The data showed that maximum flame speed increased with temperature at an increasing rate. The percentage change in flame speed with change in initial temperature for the three fuels followed the decreasing order, methane, propane, and ethylene" (p. 105).
This paper gives some quantitative measurements of wind tunnel turbulence and its effect on the air resistance of spheres and airship models, measurements made possible by the hot wire anemometer and associated apparatus in its original form was described in Technical Report no. 320 and some modifications are presented in an appendix to the present paper. One important result of the investigation is a curve by means of which measurements of the air resistance of spheres can be interpreted to give the turbulence quantitatively. Another is the definite proof that the discrepancies in the results on the N. P. L. Standard airship models are due mainly to differences in the turbulences of the wind tunnels in which the tests were made.
Report presenting an investigation in the supersonic blowdown tunnel to determine the effects of an external store on the lift, drag, and pitching-moment characteristics of an unswept wing of aspect ratio 4 at Mach numbers of 1.41, 1.62, and 1.96.
Report presenting temperature data for air-cooled turbine rotor blades obtained during an experimental investigation conducted in an altitude test chamber to determine some of the problems pertinent to the operation of air-cooled turbojet engines at a range of turbine-inlet temperatures. Results regarding local blade temperatures, effect of blade-inlet cooling-air temperature on average rotor blade temperature with two types of cooling, effect of cooling-air flow on average rotor blade temperature for a range of turbine-inlet temperatures, cooling-air flow requirements, and blade temperature correlation are provided.
Report presenting an investigation to determine the effects of a number of leading-edge flaps on the aerodynamic characteristics in pitch of a wing-fuselage configuration with a 45 degree sweptback wing. All of the flaps were found to reduce the drag in the medium lift range , but there were no significantly large effects on the lift characteristics for any of the arrangements studied.
The brake internal efficiency of the highly loaded two-stage turbine was 0.79 equivalent design work and speed. The maximum brake internal efficiency was 0.84. A radial survey revealed these major defects: (1) the first-rotor throat area was too large, and a large area of underturned flow existed near the tip;(2) considerable underturning existed at the second-stator outlet; and (3) tangential components of velocity at the turbine outlet amounted to 2.5 points in turbine efficiency.
"An investigation has been made in the Langley 4- by 4-foot supersonic pressure tunnel at a Mach number of 1.41 to determine the aerodynamic characteristics of an 0.03-scale model of the Avro CF-105 airplane. The investigation included the determination of the static longitudinal and lateral stability, the control and the hinge-moment characteristics of the elevator, the aileron, and the rudder, as well as the vertical-tail-load characteristics. The results indicated a minimum drag coefficient of about 0.0270, and a maximum trimmed lift-drag ratio of about 4.25 which occurs at a lift coefficient of 0.16" (p. 1).
Memorandum presenting an investigation of the ditching characteristics of a jet transport airplane with various engine installations. A dynamic model was used to determine the probable ditching behavior in calm water and the best ditching procedure. Various conditions of damage, engine installations, landing attitude, and speed were investigated.
Memorandum presenting an experimental investigation on a production-model turbojet engine modified by the substitution of special combustors and air-cooled turbine stator and rotor assemblies to determine some of the problems pertinent to the operation of air-cooled engines at turbine-inlet temperatures over 2200 degrees R. The investigation was conducted in an altitude chamber at simulated altitudes of 50,000 and 60,000 feet and a simulated flight Mach number of 0.8. Results regarding the combustion system, turbine stator, turbine rotor blades, turbine disks, and tailcone and other engine parts are provided.
Memorandum presenting the effects of rivets and lap joints on the drag of bodies at zero lift at supersonic Mach numbers to 2.1 in free flight with rocket-propelled models. Four forward-facing lap joints 0.064 inch high, four similar lap joints facing rearward, and four double rows of 1/8-inch-diameter brazier head rivets were tested on a 5-inch-diameter body 56 inches long.
Report presenting a flight investigation using four rocket-propelled models of low-aspect-ratio tailless configurations between Mach numbers 0.7 and 1.35. The configurations investigated were a 45 degree delta model with NACA 63A010 airfoil sections parallel to free stream, a 45 degree delta-wing model with NACA 63A006 airfoil sections parallel to free stream, a 37.5 degree swept-tapered wing model with NACA 64(sub 1)A012 sections perpendicular to quarter chord, and a 39 degree swept-tapered-wing model with NACA 64A006 airfoil sections perpendicular to quarter chord. Results regarding time histories, static longitudinal stability, dynamic longitudinal stability, order of oscillation frequency, rotational damping in pitch, and drag are provided.
The variation of the intensity of buffeting experienced throughout the operational region of the semitailless Northrop X-4 airplane and the values of maximum and peak normal-force coefficients in the Mach number range from 0.42 to 0.92 have been determined. The results are compared with data obtained with the swept-wing Douglas D-558-II airplane.
"A summary has been made of available data on the characteristics of airfoil sections with trailing-edge high-lift devices. Data for plain, split, and slotted flaps are collected and analyzed. The effects of each of the variables involved in the design of the various types of flap are examined and, in cases where sufficient data are given, optimum configurations are deduced" (p. 1).
"Tabulated pressure coefficients and aerodynamic characteristics obtained in flight from pressure distributions over six chordwise rows of orifices on the right wing of the D-558-I research airplane (BuAero No. 37972) are presented. The data were obtained through a Mach number range of 0.80 to 0.89 and throughout the normal-force-coefficient range at Mach numbers of 0.61, 0.70, 0.855, and 0.88. This paper supplements similar tabulated data which have been presented in NACA RM L50J10 and NACA RM L50L12a" (p. 1).
Report presenting an investigation to determine the effects of turbine-blade coatings, supplied by fuel additives, on heat transfer with combustor exhaust gases to an S-816 alloy blade. Two fuel additives were used. The results indicated that the fuel additives provided an oxide coating on the combustor-liner wall and other metal parts, including the blade, exposed to the exhaust gas.
This report presents the results of wind tunnel tests to determine the effectiveness of various methods of reducing the high control forces of unbalanced upper-surface ailerons and of unbalanced split flaps. A balanced split flap was developed that required control forces about half those of the unbalanced split flap when the balanced split flap was deflected to give approximately the same maximum lift.
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