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  Partner: UNT Libraries Government Documents Department
 Serial/Series Title: NACA Technical Reports
 Collection: National Advisory Committee for Aeronautics Collection
The problem of cooling an air-cooled cylinder on an aircraft engine

The problem of cooling an air-cooled cylinder on an aircraft engine

Date: January 1, 1941
Creator: Brevoort, M J & Joyner, U T
Description: An analysis of the cooling problem has been to show by what means the cooling of an air-cooled aircraft engine may be improved. Each means of improving cooling is analyzed on the basis of effectiveness in cooling with respect to power for cooling. The altitude problem is analyzed for both supercharged and unsupercharged engines. The case of ground cooling is also discussed. The heat-transfer process from the hot gases to the cylinder wall is discussed on the basis of the fundamentals of heat transfer and thermodynamics. Adiabatic air-temperature rise at a stagnation point in compressible flow is shown to depend only on the velocity of flow.
Contributing Partner: UNT Libraries Government Documents Department
An apparatus for measuring rates of discharge of a fuel-injection system

An apparatus for measuring rates of discharge of a fuel-injection system

Date: January 1, 1941
Creator: Dutee, Francis J
Description: A portable apparatus for rapidly determining rates of discharge of a fuel-injection system is described. Satisfactory operation of this apparatus with injection-pump speeds up to 2400 r.p.m was obtained. Rate-of-discharge tests were made with several cam-plunger-valve injection systems with long injection tubes. A check valve designed to reduce secondary discharges was tested. This check valve was operated with injection-pump speeds up to 2400 r.p.m without the occurrence of large secondary discharges.
Contributing Partner: UNT Libraries Government Documents Department
Analysis and prediction of longitudinal stability of airplanes

Analysis and prediction of longitudinal stability of airplanes

Date: January 1, 1941
Creator: Gilruth, R R & White, M D
Description: An analysis has been made of the longitudinal stability characteristics of 15 airplanes as determined in flight. In the correlation of satisfactory and unsatisfactory characteristics with determined values, the derivative that expresses the ratio of static-restoring moments to elevator-control moments was found to represent most nearly the stability characteristics appreciated by the pilots. The analysis was extended to study the effects of various design features on the observed stability characteristics. Design charts and data are included that show the effects on longitudinal stability of relative positions of wing and tail, fuselage size and location, engine nacelles, and horizontal-tail arrangements.
Contributing Partner: UNT Libraries Government Documents Department
Preignition characteristics of several fuels under simulated engine conditions

Preignition characteristics of several fuels under simulated engine conditions

Date: January 1, 1941
Creator: Spencer, R C
Description: The preignition characteristics of a number of fuels have been studied under conditions similar to those encountered in an engine. These conditions were simulated by suddenly compressing a fuel-air mixture in contact with an electrically heated hot spot in the cylinder head of the NACA combustion apparatus. Schlieren photographs and indicator cards were taken of the burning, and the hot-spot temperatures necessary to cause ignition under various conditions were determined.
Contributing Partner: UNT Libraries Government Documents Department
Determination of ground effect from tests of a glider in towed flight

Determination of ground effect from tests of a glider in towed flight

Date: January 1, 1940
Creator: Wetmore, J W & Turner, L I , Jr
Description: Report presents the results of an investigation made to find the effect of ground on the aerodynamic characteristics of a Franklin PS-2 glider. The lift, the drag, and the angle of attack of the glider in towed flight were determined at several heights from 0.14 to 1.19 span lengths and at various speeds for each height. Two wing arrangements were tested: the plain wing, and the wing with a nearly full-span 30-percent-chord split flap deflected 45 degrees. The experimental results for the plain wing were in good agreement with theoretical values calculated by the method of Wieselsberger for both the angle of attack and the drag coefficient at a height of 0.21 span length; Tani's refinements of the theory had a practically negligible effect on the computed values in this case.
Contributing Partner: UNT Libraries Government Documents Department
Effective gust structure at low altitudes as determined from the reactions of an airplane

Effective gust structure at low altitudes as determined from the reactions of an airplane

Date: January 1, 1940
Creator: Donely, Philip
Description: Measurements of gust structure and gust intensity were made in the lower levels of the atmosphere (0 to 3,500 ft.). An Aeronca C-2 airplane was used as the measuring instrument, the gust structure being derived from the recorded motions of the airplane. Data were also obtained on wind velocities and temperatures as functions of altitude for use in attempting to correlate the gust-structure data with various meteorological quantities. The results indicated little or no correlation between the gust velocity and the gradient distance. The data, however, did indicate that an airplane the size of the Aeronca will respond most frequently to gusts having gradient distance of the order of 30 feet. The maximum true gust velocity measured during the investigation was 25 feet per second.
Contributing Partner: UNT Libraries Government Documents Department
Free-spinning wind-tunnel tests of a low-wing monoplane with systematic changes in wings and tails V : effect of airplane relative density

Free-spinning wind-tunnel tests of a low-wing monoplane with systematic changes in wings and tails V : effect of airplane relative density

Date: January 1, 1940
Creator: Seidman, Oscar & Neihouse, A I
Description: The reported tests are a continuation of an NACA investigation being made in the free-spinning wind tunnel to determine the effects of independent variations in load distribution, wing and tail arrangement, and control disposition on the spin characteristics of airplanes. The standard series of tests was repeated to determine the effect of airplane relative density. Tests were made at values of the relative-density parameter of 6.8, 8.4 (basic), and 12.0; and the results were analyzed. The tested variations in the relative-density parameter may be considered either as variations in the wing loading of an airplane spun at a given altitude, with the radii of gyration kept constant, or as a variation of the altitude at which the spin takes place for a given airplane. The lower values of the relative-density parameter correspond to the lower wing loadings or to the lower altitudes of the spin.
Contributing Partner: UNT Libraries Government Documents Department
Wind-tunnel investigation of NACA 23012 airfoil with various arrangements of slotted flaps

Wind-tunnel investigation of NACA 23012 airfoil with various arrangements of slotted flaps

Date: January 1, 1939
Creator: Wenzinger, Carl J & Harris, Thomas A
Description: An investigation was made in the NACA 7 by 10-foot wind tunnel of a large-chord NACA 23012 airfoil with several arrangements of 25.66 percent chord slotted flaps to determine the section aerodynamic characteristics as affected by slot shape, flap shape, flap location, and flap deflection. The flap position for maximum lift, the polars for arrangements considered favorable for take-off and climb, and the complete section aerodynamic characteristics for selected optimum arrangements were determined. A discussion is given of the relative merits of the various arrangement for certain selected criterions. A comparison is made of a slotted flap on the NACA 23021 airfoil with a corresponding slotted flap previously developed for the NACA 23012 airfoil.
Contributing Partner: UNT Libraries Government Documents Department
Cooling on the front of an air-cooled engine cylinder in a conventional engine cowling

Cooling on the front of an air-cooled engine cylinder in a conventional engine cowling

Date: January 1, 1939
Creator: Brevoort, M J & Joyner, U T
Description: Measurements were made of the cooling on the fronts of model cylinders in a conventional cowling for cooling in both the ground and the cruising conditions. The mechanisms of front and rear cooling are essentially different. Cooling on the rear baffled part of the cylinders continually increases with increasing fin width. For the front of the cylinder, an optimum fin width was found to exist beyond which an increase in width reduced the heat transfer. The heat transfer coefficient on the front of the cylinders was larger on the side of the cylinder facing the propeller swirl than on the opposite side. This effect became more pronounced as the fin width was increased. These results are introductory to the study of front cooling and show the general effect of several test parameters.
Contributing Partner: UNT Libraries Government Documents Department
Experimental verification of the theory of oscillating airfoils

Experimental verification of the theory of oscillating airfoils

Date: January 1, 1939
Creator: Silverstein, Abe & Joyner, Upshur T
Description: Measurements have been made of the lift on an airfoil in pitching oscillation with a continuous-recording, instantaneous-force balance. The experimental values for the phase difference between the angle of attack and the lift are shown to be in close agreement with theory.
Contributing Partner: UNT Libraries Government Documents Department