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Increase in Maximum Pressures Produced by Preignition in Internal Combustion Engines
Report discusses the calculations that can be used to show why pressures inside an engine during preignition are higher than average. This information can be used to design a safer engine that is able to contain the increased pressure and heat generated during preignition.
Date:
August 1920
Creator:
Sparrow, S. W.
System:
The UNT Digital Library
The Problem of the Turbo-Compressor
"In terminating the study of the adaptation of the engine to the airplane, we will examine the problem of the turbo-compressor, the first realization of which dates from the war; this will form an addition to the indications already given on supercharging at various altitudes. This subject is of great importance for the application of the turbo-compressor worked by the exhaust gases. Assuming that the increase of pressure in the admission manifold is the same in both cases, the pressure in the exhaust manifold would be greater in the case in which the compressor is worked by the exhaust gas and there would result a certain reduction of engine power which we must be able to calculate" (p. 1).
Date:
August 1920
Creator:
Devillers, René
System:
The UNT Digital Library
Soaring Flight in Guinea
Report discusses information obtained from studying large birds that fly by soaring, which involves using the wind without moving their wings. An Egyptian vulture and African white-backed vulture were observed and their relative air speed, upward air velocity, lift, and drag were noted. The experimental methods for measuring these values are described.
Date:
August 1920
Creator:
Idrac, Pierre
System:
The UNT Digital Library
Theory of Lifting Surfaces, Part 2
A mathematical model is presented towards a theory of lifting and resistance on wings. It consists hide of a theory of multiplanes, conditions of flow at a great distance from the wing, lifting systems of minimum resistance, and free stream and stream limited by walls.
Date:
August 1920
Creator:
Prandtl, L.
System:
The UNT Digital Library
The Employment of Airships for the Transport of Passengers: Indications on the Maximum Limits of Their Useful Load, Distance Covered, Altitude and Speed
It was a conclusion of this detailed study of the practicality of using airships for carrying passengers that, although slow, airships are capable of carrying useful loads over long distances. However, it is noted that there is a certain limit to the advantages of large cubature. Beyond a certain point, the maximum altitude of the airship goes on decreasing, in spite of the fact that the range of action in the horizontal plane and the useful load go on increasing. The possibility of rapid climb is an essential factor of security in aerial navigation in the case of storms, as is velocity.
Date:
August 1921
Creator:
Nobile, Umberto
System:
The UNT Digital Library
A New Method of Testing in Wind Tunnels
Now, in existing wind tunnels, using a horsepower of 100 to 300, the models are generally made to a 1/10 scale and the speed is appreciably lower than the speeds currently attained by airplanes. The Reynolds number realized is thus 15 to 25 times smaller than that reached by airplanes in free flight, while the ratio of speed to the velocity of sound is between a third and three quarters of the true ratio. The necessary increases in either the diameter of the wind tunnel or the velocity of the airstream are too costly.
Date:
August 1921
Creator:
Margoulis, W.
System:
The UNT Digital Library
Structural Safety During Curved Flight
Note presenting an exploration of aircraft safety during curved flight, which leads to more stress on the wings than other types of flight.
Date:
August 1922
Creator:
Rohrbach, Adolf
System:
The UNT Digital Library
Test of Oil Scraper Piston Ring and Piston Fitted With Oil Drain Holes
Tests were conducted to determine whether or not a properly located and properly designed oil scraper piston ring, installed on a piston provided with oil drain holes of sufficient area, would prevent the excessive oiling of the Liberty engine, particularly with the engine running at idling speed with full oil pressure. Results showed that excessive oiling was in fact prevented. It is strongly recommended that scraper rings and pistons be adopted for aircraft engines.
Date:
August 1922
Creator:
McDewell, H. S.
System:
The UNT Digital Library
The twisted wing with elliptic plan form
A method for computing the aerodynamic induction of wings with elliptic plan form if arbitrarily twisted.
Date:
August 1922
Creator:
Munk, Max M.
System:
The UNT Digital Library
The Use of Multiplied Pressures for Automatic Altitude Adjustments
"The efficient performance of an airplane requires that certain adjustments be made as the density of the air through which the airplane passes changes. The safety of the over-dimensioned aircraft engine depends upon careful manipulation of spark advance and throttle opening and a proper control of a variable pitch propeller, if the maximum performance of the supercharged engine is to be obtained. It is evident that there is a real need for satisfactory devices to make such adjustments automatically. Discussed here is a method of automatic compensation which deserves consideration in the design of such devices" (p. 1).
Date:
August 1922
Creator:
Sparrow, Stanwood W.
System:
The UNT Digital Library
Flight Characteristics
Note presenting some comparative performances of new types of airplanes under the same conditions. The airplanes were compared with some that are already in use and give an accurate idea of the progress shown in the new types.
Date:
August 1923
Creator:
Student
System:
The UNT Digital Library
An instrument for recording the position of airplane control surfaces
N.A.C.A. has developed an instrument which makes a continuous record of the angular position of the control surfaces of an airplane, not only in steady flight but during acrobatics as well. It has proven useful in researches into stability and controllability, and from records obtained from it many otherwise obscure details of piloting technique have been available for the instruction of pilots, from novices to seasoned experts.
Date:
August 1923
Creator:
Ronan, K. M.
System:
The UNT Digital Library
The N.A.C.A. Recording Tachometer and Angle of Attack Recorder
This note contains photos and descriptions of airplane flight apparatus for use in conjunction with a recording galvanometer. In measuring the angle of attack a variable resistance is used, being controlled by a vane in the airstream. Thus it is only necessary to measure the change of resistance.
Date:
August 1923
Creator:
Reid, H. J. E.
System:
The UNT Digital Library
Regulations Governing the Issuance of Certificates of Airworthiness of Aircraft in France
"These regulations, approved by the Under Secretary of State for Aeronautics, in a ministerial decree 1124/2a, Feb. 19, 1923, cancels the regulations of Aug. 31, 1920, and supplements the decree of Aug. 14, 1920, fixing the conditions under which certificates of airworthiness may be issued,in conformity with Article 5 of said decree" (p. 1).
Date:
August 1923
Creator:
unknown
System:
The UNT Digital Library
Tests on Built-Up Airplane Struts Having Initial Tension in Outside Fibers
"The conventional airplane strut fails by buckling. The first signs of failure usually are compression cracks on the concave side of bending. It would therefore appear that if an initial tension could be introduced in the outside fibers, this tension would have to be relieved before the compression load could make itself felt" (p. 1).
Date:
August 1923
Creator:
Schwamb, T. A. & Smith, C. S.
System:
The UNT Digital Library
Thrust and Power Required in Climbing
The following article shows that the phenomena of climbing flight can be determined with sufficient accuracy and represented very clearly, for all flight positions, by means of the thrust diagrams. This method has often given good results.
Date:
August 1923
Creator:
Koenig, Georg
System:
The UNT Digital Library
Micarta Propellers 1: Materials
Here, values for tension, compression edgewise of laminations, and transverse flatwise of laminations are given for Micarta made with various kinds of sheet material. The corresponding values for white oak are given for comparison. It was found by destructive and service tests that Micarta made with a good grade of cotton duck will give satisfactory service with most designs.
Date:
August 1924
Creator:
Caldwell, F. W. & Clay, N. S.
System:
The UNT Digital Library
Micarta Propellers 2: Method of Construction
The methods used in manufacturing Micarta propellers differ considerably from those employed with wood propellers on account of the hardness of the materials. The propellers must be formed accurately to size in a mold and afterwards balanced without the customary trimming of the material from the tips. Described here are the pressing and molding processes, filing, boring, balancing, and curing.
Date:
August 1924
Creator:
Caldwell, F. W. & Clay, N. S.
System:
The UNT Digital Library
Micarta Propellers III: General Description of the Design
The design of propellers made of Micarta is discussed. The advantages of the material are noted, especially as compared with wood. The design changes necessitated by the use of Micarta are discussed with reference to the hub boss, the narrowing of the blade tips, the thinning of the blades, the angles of the leading and trailing edges, and the adjustment of the pitch. Results of flight tests show that the Micarta propeller gave a top speed of 2 miles per hour more than the wooden propeller while turning about 120 r.p.m slower, with about the same rate of climb.
Date:
August 1924
Creator:
Caldwell, F. W. & Clay, N. S.
System:
The UNT Digital Library
Air Flow Investigation for Location of Angle of Attack Head on a JN4h Airplane
The technical staff of the NACA at Langley Field, has made a series of free flight tests with a JN4h airplane in order to find the best place for an instrument for measuring the angle of attack. A "neutral zone" was found where the air remains either at rest relative to the undisturbed air beyond the influence of the airplane, or is set in motion parallel to the motion of the airplane. This zone is about midway between the two wings and slightly in front of, or at the vertical plane through the leading edges of the wings but the exact position as well as the outlines of the zone varies considerably as the conditions of flight change.
Date:
August 1925
Creator:
Freeman, R. G.
System:
The UNT Digital Library
Determination of the Lift and Drag Characteristics of an Airplane in Flight
Flight tests to determine lift and drag characteristics are discussed. A review is given of the fundamental principles on which the tests are based and on the forces acting on an airplane in the various conditions of steady flight. Glide with and without propeller thrust and the relation between angle of attack and the indicated airspeed for different conditions of steady flight are discussed. The glide test procedure and the problem of the propeller are discussed.
Date:
August 1925
Creator:
Green, Maurice W.
System:
The UNT Digital Library
Pressure Distribution on the Nose of an Airship in Circling Flight
In recent tests on the pressures occurring on the envelope and control surfaces of the naval airship C-7, it was noted that the pressures on the nose of the airship, while flying in level circling flight, were symmetrically distributed. Such a condition can only occur when the nose of the airship is pointed directly into the wind, and to accomplish this in circling flight, the axis of the airship must then be parallel to the direction of the motion of the nose. The question was raised as to whether the same conditions occur generally on all airships in circling flight.
Date:
August 1925
Creator:
Fairbanks, Karl J.
System:
The UNT Digital Library
The characteristics of the N.A.C.A. M-12 airfoil section
The data obtained on the NACA M-12 airfoil, tested at twenty atmosphere density in the NACA variable density wind tunnel, have been extended by additional tests at one and at twenty atmospheres under improved conditions. The results of these tests are given. Considerable scale effect was found.
Date:
August 1926
Creator:
Higgins, George J.
System:
The UNT Digital Library
Navy Propeller Section Characteristics as Used in Propeller Design
"This report contains artificial aerodynamic characteristics of a set of propeller sections to be used in designing propellers by means of the blade element theory. Characteristics computed from model propeller tests for a single section are extended to cover sections of Navy propeller sections at high Reynolds Number in the variable density tunnel of the NACA" (p. 1).
Date:
August 1926
Creator:
Weick, Fred E.
System:
The UNT Digital Library