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  Partner: UNT Libraries Government Documents Department
 Decade: 1930-1939
 Collection: National Advisory Committee for Aeronautics Collection
A comparison of the aerodynamic characteristics of the normal and three reflexed airfoils in the variable density wind tunnel

A comparison of the aerodynamic characteristics of the normal and three reflexed airfoils in the variable density wind tunnel

Date: August 1, 1931
Creator: Defoe, George L
Description: An investigation was made of the aerodynamic effects of reflexing the trailing edge of three commonly used airfoils. Six airfoils were used in the investigation: three having the normal profiles of the Navy 60, the Boeing 106, and the Gottingen 398, and three having these profiles modified to obtain a reflexed trailing edge with the mean camber line changed to give Cmc/4=0. The tests were conducted at a value of the Reynolds Number of approximately 3,100,000 in the variable density wind tunnel of the National Advisory Committee for Aeronautics. Measurements of lift, drag, and pitching moment were made on each of the six airfoils. The expected reduction of the center of pressure travel was obtained. The maximum lift was reduced approximately 12 per cent and the minimum profile drag approximately 4 per cent.
Contributing Partner: UNT Libraries Government Documents Department
An investigation of airplane landing speeds

An investigation of airplane landing speeds

Date: September 1, 1930
Creator: Ridley, Kenneth F
Description: This paper describes an investigation on airplane landing speeds which was made to determine the applicability of accepted aerodynamic theory to the prediction of this particular performance characteristic. The experimental work consisted in measuring the landing speed of several monoplanes by a new photographic method. The results of these tests supplemented by available information regarding biplanes were compared with predictions made with basic aerodynamic theory. The prediction makes use of the fundamental relation between wing loading, lift coefficient, and speed of level flight, and the effects of aspect ratio and proximity to the ground on lift curve slope.
Contributing Partner: UNT Libraries Government Documents Department
The N.A.C.A. apparatus for studying the formation and combustion of fuel sprays and the results from preliminary tests

The N.A.C.A. apparatus for studying the formation and combustion of fuel sprays and the results from preliminary tests

Date: September 1, 1931
Creator: Rothrock, A M
Description: Described here is an apparatus for studying the formation and combustion of fuel sprays under conditions closely simulating those in a high speed compression-ignition engine. The apparatus consists of a single-cylinder modified test engine, a fuel injection system so designed that a single charge of fuel can be injected into the combustion chamber, an electric driving motor, and a high-speed photographic apparatus. The cylinder head of the engine has a vertical disk form of combustion chamber whose sides are glass windows. When the fuel is injected into the combustion chamber, motion pictures at the rate of 2000 per second are taken of the spray formation by means of spark discharges. When combustion takes place, the light of combustion is recorded on the same photographic film as the spray photographs. Included here are the results of some tests to determine the effect of air temperature, air flow, and nozzle design on the spray formation. The results show that the compression temperature has little effect on the penetration of the fuel spray, but does not affect the dispersion, that air velocities of about 300 feet per second are necessary to destroy the core of the spray, and that the effect of air ...
Contributing Partner: UNT Libraries Government Documents Department
Span load distribution on two monoplanes wing models as affected by twist and sweepback

Span load distribution on two monoplanes wing models as affected by twist and sweepback

Date: July 1, 1930
Creator: Knight, Montgomery
Description: The results presented in this note show the effect of twist and sweepback on the span load distribution over two monoplane wing models. The tests were made in the Atmospheric Wind Tunnel of the Langley Memorial Aeronautical Laboratory. The data are taken from the results of an investigation dealing primarily with lateral stability. As presented, they are suitable as an aid in the structural design of certain monoplane wings.
Contributing Partner: UNT Libraries Government Documents Department
The prevention of the ice hazard on airplanes

The prevention of the ice hazard on airplanes

Date: July 1, 1930
Creator: Geer, William C
Description: A review of various methods to prevent ice formation and adhesion to aircraft surfaces is given. It was concluded that the adhesion of ice to a surface may be reduced somewhat by the application of certain waxes and varnishes. In the experiments described, the varnishes containing calcium stearate and calcium oleate gave the best results. In wind tunnel tests, the adhesion was further reduced by the application of these waxes and varnishes to a thin, heat insulating layer of rubber. The adhesion of ice is greatly reduced when the surface consists of a vehicle which carries an oil in sufficient quantity so that the surface of the vehicle is self lubricating. Ice may be removed from wings, struts, wires and other parts of an airplane during flight by the inflation of properly constructed pneumatic rubber members, providing that these members have been previously treated with a suitable low adhesion oil.
Contributing Partner: UNT Libraries Government Documents Department
Alterations and tests of the "Farnboro" engine indicator

Alterations and tests of the "Farnboro" engine indicator

Date: September 1, 1930
Creator: Collins, John H , Jr
Description: The 'Farnboro' electric indicator was tested as received from the manufacturers, and modifications made to the instrument to improve its operation. The original design of disk valve was altered so as to reduce the mass, travel, and seat area. Changes were made to the recording mechanism, which included a new method of locating the top center position on the record. The effect of friction on the motion of the pointer while taking motoring and power cards was eliminated by providing a means of putting pressure lines on the record. The modified indicator gives a complete record of the average cyclic variation in pressure per crank degree for any set of engine operating conditions which can be held constant for the period of time required to build up the composite card. The value of the record for accurate quantitative measurement is still questioned, although the maximum indicated pressure recorded on the motoring and power cards checks the readings of the balanced diaphragm type of maximum cylinder pressure indicator.
Contributing Partner: UNT Libraries Government Documents Department
Pressure distribution over a Douglas wing tip on a biplane in flight

Pressure distribution over a Douglas wing tip on a biplane in flight

Date: August 1, 1930
Creator: Rhode, Richard V
Description: This note presents the results obtained in pressure distribution tests on the right upper wing panel and tip of a Douglas M-3 airplane in flight. These tests are a part of a more extensive investigation of the effect of changes in tip shape on the load distribution, the tip reported herein being the first of a series of tip shapes being tested. The results are given in tables and curves in such form that the load distribution for any conditions may be determined easily. Tests were made at Langley Field by the NACA in the spring of 1930.
Contributing Partner: UNT Libraries Government Documents Department
Strength in shear of the thin curved sheets of Alclad

Strength in shear of the thin curved sheets of Alclad

Date: June 1, 1930
Creator: Smith, George Michael
Description: This note is on an investigation made to obtain information on the strength of thin curved sheets of Alclad in shear. Designers may utilize this material as a strength member as well as for a covering for the wings and fuselages. A reduction may then be made in the size of the internal strength members. These experiments were undertaken with the object of securing the maximum value from the metal in this respect. The point at which buckling occurs is of primary importance. The buckling shear of a curved thin plate was determined mathematically and also experimentally. The following formula was obtained mathematically: s=K E t/r in which s is the unit shear, K is a constant, E is the modulus of elasticity, t is the thickness of the material, and r is the radius of curvature. The value of K as determined by the experiments was found to be .075. This formula applies only when s is within the elastic limit of the material. The breaking point of the material was obtained in most of the tests as a matter of information and the results are included in this report. The effect of the supporting ribs was determined by ...
Contributing Partner: UNT Libraries Government Documents Department
Determination of the profile drag of an airplane wing in flight at high Reynolds numbers

Determination of the profile drag of an airplane wing in flight at high Reynolds numbers

Date: January 1, 1939
Creator: Bicknell, J.
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Comparison of free-spinning wind-tunnel results with corresponding full-scale spin results

Comparison of free-spinning wind-tunnel results with corresponding full-scale spin results

Date: December 1, 1938
Creator: NEIHOUSE A I
Description: None
Contributing Partner: UNT Libraries Government Documents Department
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