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N.A.C.A. Stall-Warning Device

Description: With some airplanes the approach to the stall is accompanied by changes in the behavior, such as tail buffeting or changes in the control characteristics of the airplane so that the pilot obtains a warning of the impending stall. Vith other airplanes it is possible to approach the stall without any perceptible warning other than the reading of the air-speed meter, in which case the danger of inadvertent stalling is considerably greater. Although it is not within the scope of this paper to discu… more
Date: February 1938
Creator: Thompson, F. L.
open access

Accelerations in Landing with a Tricycle-Type Landing Gear

Description: "In connection with the application of stable tricycle-type landing gears to transport airplanes, the question arises as to whether certain passengers may not experience relatively great accelerations in an emergency landing. Since the main landing wheels are behind the center of gravity in this type of gear, a hard-braked landing will cause immediate nosing down of the airplane and, when this motion is stopped due to the front wheel striking the ground, there will be some tendency for the rear… more
Date: February 1937
Creator: Jones, Robert T.
open access

The Effect of Surface Irregularities on Wing Drag 1 - Rivets and Spot Welds

Description: "Tests have been conducted in the NACA 8-foot high-speed wind tunnel to determine the effect of exposed rivet heads and spot welds on wing drag. Most of the tests were made with an airfoil of 5-foot chord. The air speed was varied from 80 to 500 miles per hour and the lift coefficient from 0 to 0.30" (p. 1).
Date: February 1938
Creator: Hood, Manley J.
open access

The Effect of Surface Irregularities on Wing Drag 2 - Lap Joints

Description: Tests have been made in the NACA 8-foot high-speed wind tunnel of the drag caused by four types of lap joint. The tests were made on an airfoil of NACA 23012 section and 5-foot chord and covered in a range of speeds from 80 to 500 miles per hour and lift coefficients from 0 to 0.30. The increases in profile drag caused by representative arrangements of laps varied from 4 to 9%. When there were protruding rivet heads on the surface, the addition of laps increased the drag only slightly. Laps on … more
Date: February 1938
Creator: Hood, Manley J.
open access

The Effect of Surface Irregularities on Wing Drag 3 - Roughness

Description: "Tests have been made in the N.A.C.A. 8-foot high-speed wind tunnel of the drag caused by roughness on the surface of an airfoil of N.A.C.A. 23012 section and 5-foot chord. The tests were made at speeds from 80 to 500 miles per hour at lift coefficients from 0 to 0.30. For conditions corresponding to high-speed flight, the increase in the drag was 30 percent of the profile drag of the smooth airfoil for the roughness produced by spray painting and 63 percent for the roughness produced. by 0.003… more
Date: February 1938
Creator: Hood, Manley J.
open access

The Effect of Surface Irregularities on Wing Drag 4 - Manufacturing Irregularities

Description: "Tests were made in the NACA 8-foot high speed wind tunnel of a metal-covered, riveted, 'service' wing of average workmanship to determine the aerodynamic effects of the manufacturing irregularities incident to shop fabrication. The wing was of 5-foot chord and of NACA 23012 section and was tested in the low-lift range at speeds from 90 to 450 miles per hour corresponding to Reynolds numbers from 4,000,000 to 18,000,000. At a cruising condition the drag of the service wing was 46% higher than t… more
Date: February 1938
Creator: Robinson, Russell G.
open access

Experimental Determination of Exhaust Gas Thrust, Special Report

Description: "This investigation presents the results of tests made on a radial engine to determine the thrust that can be obtained from the exhaust gas when discharged from separate stacks and when discharged from the collector ring with various discharge nozzles. The engine was provided with a propeller to absorb the power and was mounted on a test stand equipped with scales for measuring the thrust and engine torque. The results indicate that at full open throttle at sea level, for the engine tested, a g… more
Date: February 1940
Creator: Pinkel, Benjamin & Voss, Fred
open access

NACA Radio Ground-Speed System for Aircraft, Special Report

Description: "A method that utilizes the Doppler effect on radio signals for determining the speed of an airplane and the distance traveled by the airplane has been developed and found to operate satisfactorily. In this method, called the NACA radio ground-speed system, standard readily available radio equipment is used almost exclusively and extreme frequency stability of the transmitters is not necessary. No complicated equipment need be carried in the airplane, as the standard radio transmitter is usuall… more
Date: February 1943
Creator: Hastings, Charles E.
open access

Preliminary Investigation of the Effect of Compressibility on the Maximum Lift Coefficient, Special Report

Description: "Preliminary data are presented on the variation of the maximum lift coefficient with Mach number. The data were obtained from tests in the 8-foot high-speed tunnel of three NACA 16-series airfoils of 1-foot chord. Measurements consisted primarily of pressure-distribution measurements in order to illustrate the nature of the phenomena. It was found that the maximum lift coefficient of airfoils is markedly affected by compressibility even at Mach numbers as low as 0.2" (p. 1).
Date: February 1943
Creator: Stack, John; Fedziuk, Henry A. & Cleary, Harold E.
open access

Preliminary Model Tests of a Wing-Duct Cooling System for Radial Engines, Special Report

Description: "Wind-tunnel tests were conducted on a model wing-nacelle combination to determine the practicability of cooling radial engines by forcing the cooling air into wing-duct entrances located in the propeller slipstream, passing the air through the engine baffles from rear to front, and ejecting the air through an annular slot near the front of the nacelle. The drag of the cowlings tested was definitely less than for the conventional N.A.C.A. cowling, and the pressure available at low air speed cor… more
Date: February 1939
Creator: Biermann, David & Valentine, E. Floyd
open access

Wind-Tunnel Tests of the NACA 45-125 Airfoil: A Thick Airfoil for High-Speed Airplanes

Description: Report discussing an investigation of the pressure distribution, profile drag, and location of transition for a NACA 45-125 airfoil for the purpose of aiding in the development of a thick wing for high-speed airplanes. The critical speed, pressure distribution, and drag of the airfoil are detailed.
Date: February 1940
Creator: Delano, James B.
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