Aerodynamic characteristics of a 6-percent-thick symmetrical double-wedge airfoil at transonic speeds from tests by the NACA wing-flow method (open access)

Aerodynamic characteristics of a 6-percent-thick symmetrical double-wedge airfoil at transonic speeds from tests by the NACA wing-flow method

From Introduction: "The investigation covered a range of Mach numbers from 0.66 to 1.12 and included measurements of angle of attack, pitching moment, normal force, and chord force. The drag at zero lift obtained in this investigation was reported in reference 1, but without the correction for tare of the end plate."
Date: March 4, 1949
Creator: Lina, Lindsay J.
System: The UNT Digital Library
Analysis and Experimental Observation of Pressure Losses in Ram-Jet Combustion Chambers (open access)

Analysis and Experimental Observation of Pressure Losses in Ram-Jet Combustion Chambers

From Introduction: "Some experimental data on flame-holder pressure losses have been presented (reference 1 to 4). A theoretical analysis that assume a sudden enlargement of flow area was made at the NACA Lewis laboratory to determine the effect of flame-holder open area and combustion-chamber-inlet Mach number on the pressure losses across flame holders. The results of this analysis were then compared with experimental data obtained with several different flame-holder designs."
Date: November 4, 1949
Creator: Sterbentz, William H.
System: The UNT Digital Library
An analysis of a highly compounded two-stroke-cycle compression-ignition engine (open access)

An analysis of a highly compounded two-stroke-cycle compression-ignition engine

This report presents an analysis of a compound engine operating with manifold pressures ranging from 60 to 110 lb/sq in. absolute and discusses the effects of engine limits (peak cylinder pressure and turbine-inlet temperature) and component efficiency.
Date: April 4, 1949
Creator: Tauschek, Max J.; Sather, Bernard I. & Biermann, Arnold E.
System: The UNT Digital Library
Direct method of design and stress analysis of rotating disks with temperature gradient (open access)

Direct method of design and stress analysis of rotating disks with temperature gradient

A method is presented for the determination of the contour of disks, typified by those of aircraft gas turbines, to incorporate arbitrary elastic-stress distributions resulting from either centrifugal or combined centrifugal and thermal effects. The specified stress may be radial, tangential, or any combination of the two. Use is made of the finite-difference approach in solving the stress equations, the amount of computation necessary in the evolution of a design being greatly reduced by the judicious selection of point stations by the aid of a design chart. Use of the charts and of a preselected schedule of point stations is also applied to the direct problem of finding the elastic and plastic stress distribution in disks of a given design, thereby effecting a great reduction in the amount of calculation. Illustrative examples are presented to show computational procedures in the determination of a new design and in analyzing an existing design for elastic stress and for stresses resulting from plastic flow.
Date: April 4, 1949
Creator: Manson, S. S.
System: The UNT Digital Library
Experimental investigation of hot-gas bleedback for ice protection of turbojet engines 3: nacelle with short straight air inlet (open access)

Experimental investigation of hot-gas bleedback for ice protection of turbojet engines 3: nacelle with short straight air inlet

Report presenting aerodynamic and icing investigations in the icing research tunnel on a model of a turbojet-engine nacelle with a short straight air inlet. The hot-gas blowback system consisted of several orifices peripherally located around the inlet and was investigated in both dry-air and icing conditions. Results regarding the aerodynamic investigation without bleedback, aerodynamic investigation with cold-gas bleedback, aerodynamic investigation with hot-gas bleedback, and icing with bleedback are provided.
Date: August 4, 1949
Creator: Ruggeri, Robert S. & Callaghan, Edmund E.
System: The UNT Digital Library
Experimental study of loop-scavenged compression-ignition cylinder for gas-generator use (open access)

Experimental study of loop-scavenged compression-ignition cylinder for gas-generator use

Report presenting an investigation of the performance and general operating characteristics of a small single-cylinder, two-stroke-cycle, loop-scavenged engine using compression ignition at low compression ratios, high inlet-manifold temperatures and high inlet-manifold and exhaust-gas pressures. Results regarding the scavenging characteristics, power output, cylinder pressures, thermal efficiency, and exhaust measurements are provided.
Date: April 4, 1949
Creator: Foster, Hampton H.; Schuricht, F. Ralph & Tauschek, Max J.
System: The UNT Digital Library
Measurements of Aileron Effectiveness of the Bell X-1 Airplane at Mach Numbers Between 0.9 and 1.06 (open access)

Measurements of Aileron Effectiveness of the Bell X-1 Airplane at Mach Numbers Between 0.9 and 1.06

"Abrupt rudder-fixed aileron rolls have been made with the Bell X-1 airplane in powered flight at Mach numbers between 0.90 and 1.06 at about 40,000 feet pressure altitude. These aileron rolls indicate that the aileron effectiveness for large deflections at Mach number 0.94 is only one-fourth the value at Mach number 0.82, and the effectiveness at Mach number 1.06 is slightly greater than at Mach number 0.94" (p. 1).
Date: August 4, 1949
Creator: Drake, Hubert M.
System: The UNT Digital Library
Spark ignition of flowing gases I : energies to ignite propane-air mixtures in pressure range of 2 to 4 inches mercury absolute (open access)

Spark ignition of flowing gases I : energies to ignite propane-air mixtures in pressure range of 2 to 4 inches mercury absolute

Ignition studies of flowing gases were made to obtain information applicable to ignition problems in gas-turbine and ram-jet aircraft propulsion systems operating at altitude conditions.Spark energies required for ignition of a flowing propane-air mixture were determined for pressure of 2 to 4 inches mercury absolute, gas velocities of 5.0 to 54.2 feet per second, fuel-air ratios of 0.0607 to 0.1245, and spark durations of 1.5 to 24,400 microseconds. The results showed that at a pressure of 3 inches mercury absolute the minimum energy required for ignition occurred at fuel-air ratios of 0.08 to 0.095. The energy required for ignition increased almost linearly with increasing gas velocity. Shortening the spark duration from approximately 25,000 to 125 microseconds decreased the amount of energy required for ignition. A spark produced by the discharge of a condenser directly into the spark gap and having a duration of 1.5 microseconds required ignition energies larger than most of the long-duration sparks.
Date: August 4, 1949
Creator: Swett, Clyde C., Jr.
System: The UNT Digital Library
Stability and Control Data Obtained from Fourth and Fifth Flights of the Northrop X-4 Airplane (A.F. No. 46-676) (open access)

Stability and Control Data Obtained from Fourth and Fifth Flights of the Northrop X-4 Airplane (A.F. No. 46-676)

"NACA instrumentation has been installed in the Northrop X-4 airplane to obtain stability and control data during the Northrop conducted acceptance tests. The results of the fourth and fifth flights of the Northrop X-4 number 1 airplane are presented in this paper. These data were obtained for a center-of-gravity position of approximately 19.5 percent of the mean aerodynamic chord. The results of this flight showed that the directional stability as measured in steadily increasing sideslips was positive and high and that the effective dihedral was positive. The results also show the airplane to be longitudinally stable, stick fixed, with the center of gravity at 19.5 percent of the mean aerodynamic chord" (p. 1).
Date: August 4, 1949
Creator: Valentine, George M.
System: The UNT Digital Library
Tests of a Full-Scale Model of the Republic XF-91 Airplane in the Ames 40- by 80-Foot Wind Tunnel. - Force and Moment Data (open access)

Tests of a Full-Scale Model of the Republic XF-91 Airplane in the Ames 40- by 80-Foot Wind Tunnel. - Force and Moment Data

"Wind-tunnel tests of a full-scale model of the Republic XF-91 airplane having swept-back wings and a vee tail were conducted to determine both the stability and control characteristics of the model longitudinally, laterally, and directionally. Configurations of the model were investigated involving such variables as external fuel tanks, a landing gear, trailing-edge flaps, leading-edge slats, and a range of wing incidences and tail incidences" (p. 1).
Date: March 4, 1949
Creator: Hunton, Lynn W. & Dew, Joseph K.
System: The UNT Digital Library