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 Serial/Series Title: NACA Technical Reports
 Collection: National Advisory Committee for Aeronautics Collection
A correlation of results of flight investigation with results of an analytical study of effects of wing flexibility on wing strains due to gusts

A correlation of results of flight investigation with results of an analytical study of effects of wing flexibility on wing strains due to gusts

Date: January 1, 1958
Creator: Shufflebarger, C C; Payne, Chester B & Cahen, George L
Description: An analytical study of the effects of wing flexibility on wing strains due to gusts has been made for four spanwise stations of a four-engine bomber airplane, and the results have been correlated with results of a previous flight investigation.
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Differential equations of motion for combined flapwise bending, chordwise bending, and torsion of twisted nonuniform rotor blades

Differential equations of motion for combined flapwise bending, chordwise bending, and torsion of twisted nonuniform rotor blades

Date: January 1, 1958
Creator: Houbolt, John C & Brooks, George W
Description: The differential equations of motion for the lateral and torsional deformations of twisted rotating beams are developed for application to helicopter rotor and propeller blades. No assumption is made regarding the coincidence of the neutral, elastic, and mass axes, and the generality is such that previous theories involving various simplifications are contained as subcases to the theory presented in this paper. Special attention is given the terms which are not included in previous theories. These terms are largely coupling-type terms associated with the centrifugal forces. Methods of solution of the equations of motion are indicated by selected examples.
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Ditching investigations of dynamic models and effects of design parameters on ditching characteristics

Ditching investigations of dynamic models and effects of design parameters on ditching characteristics

Date: January 1, 1958
Creator: Fisher, Lloyd J & Hoffman, Edward L
Description: Data from ditching investigations conducted at the Langley Aeronautical Laboratory with dynamic scale models of various airplanes are presented in the form of tables. The effects of design parameters on the ditching characteristics of airplanes, based on scale-model investigations and on reports of full-scale ditchings, are discussed. Various ditching aids are also discussed as a means of improving ditching behavior.
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Drag minimization for wings and bodies in supersonic flow

Drag minimization for wings and bodies in supersonic flow

Date: January 1, 1958
Creator: Heaslet, Max A & Fuller, Franklyn B
Description: The minimization of inviscid fluid drag is studied for aerodynamic shapes satisfying the conditions of linearized theory, and subject to imposed constraints on lift, pitching moment, base area, or volume. The problem is transformed to one of determining two-dimensional potential flows satisfying either Laplace's or Poisson's equations with boundary values fixed by the imposed conditions. A general method for determining integral relations between perturbation velocity components is developed. This analysis is not restricted in application to optimum cases; it may be used for any supersonic wing problem.
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Effect of chord size on weight and cooling characteristics of air-cooled turbine blades

Effect of chord size on weight and cooling characteristics of air-cooled turbine blades

Date: January 1, 1958
Creator: Esgar, Jack B; Schum, Eugene F & Curren, Arthur N
Description: An analysis has been made to determine the effect of chord size on the weight and cooling characteristics of shell-supported, air-cooled gas-turbine blades. In uncooled turbines with solid blades, the general practice has been to design turbines with high aspect ratio (small blade chord) to achieve substantial turbine weight reduction. With air-cooled blades, this study shows that turbine blade weight is affected to a much smaller degree by the size of the blade chord.
Contributing Partner: UNT Libraries Government Documents Department
Effect of fuel variables on carbon formation in turbojet-engine combustors

Effect of fuel variables on carbon formation in turbojet-engine combustors

Date: January 1, 1958
Creator: Jonash, Edmund R; Wear, Jerrold D & Cook, William P
Description: Report presents the results of an investigation of the effects of fuel properties and of a number of fuel additives on combustion-chamber carbon deposition and exhaust-gas smoke formation in a single tubular turbojet-engine combustor. Limited tests were conducted with a number of the fuels in several full-scale turbojet engines to verify single-combustor data.
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Elliptic cones alone and with wings at supersonic speed

Elliptic cones alone and with wings at supersonic speed

Date: January 1, 1958
Creator: Jorgensen, Leland H
Description: To help fill the gap in the knowledge of aerodynamics of shapes intermediate between bodies of revolution and flat triangular wings, force and moment characteristics for elliptic cones have been experimentally determined for Mach numbers of 1.97 and 2.94. Elliptic cones having cross-sectional axis ratios from 1 through 6 and with lengths and base areas equal to circular cones of fineness ratios 3.67 and 5 have been studied for angles of bank of 0 degree and 90 degrees. Elliptic and circular cones in combination with triangular wings of aspect ratios 1 and 1.5 also have been considered. The angle-of-attack range was from 0 degree to about 16 degrees, and the Reynolds number was 8 x 10(6), based on model length. In addition to the forces and moments at angle of attack, pressure distributions for elliptic cones at zero angle of attack have been determined. The results of this investigation indicate that there are distinct aerodynamic advantages to the use of elliptic cones.
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Experimental determination of effects of frequency and amplitude on the lateral stability derivatives for a delta, a swept, and unswept wing oscillating in yaw

Experimental determination of effects of frequency and amplitude on the lateral stability derivatives for a delta, a swept, and unswept wing oscillating in yaw

Date: January 1, 1958
Creator: Fisher, Lewis R
Description: Three wing models were oscillated in yaw about their vertical axes to determine the effects of systematic variations of frequency and amplitude of oscillation on the in-phase and out-of-phase combination lateral stability derivatives resulting from this motion. The tests were made at low speeds for a 60 degree delta wing, a 45 degree swept wing, and an unswept wing; the swept and unswept wings had aspect ratios of 4. The results indicate that large changes in the magnitude of the stability derivatives due to the variation of frequency occur at high angles of attack, particularly for the delta wing. The greatest variations of the derivatives with frequency take place for the lowest frequencies of oscillation; at the higher frequencies, the effects of frequency are smaller and the derivatives become more linear with angle of attack. Effects of amplitude of oscillation on the stability derivatives for delta wings were evident for certain high angles of attack and for the lowest frequencies of oscillation. As the frequency became high, the amplitude effects tended to disappear.
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An experimental investigation of sting-support effects on drag and a comparison with jet effects at transonic speeds

An experimental investigation of sting-support effects on drag and a comparison with jet effects at transonic speeds

Date: January 1, 1958
Creator: Cahn, Maurice S
Description: Various dummy stings were tested on the rear of a related series of afterbody shapes for Mach numbers from 0.80 to 1.10 and Reynolds numbers based on body length from 15.0 x 16 to the 6th power to 17.4 x 10 to the 6th power. A method is presented whereby approximate sting interference corrections can be made to models having afterbody shapes and sting supports similar to those of these tests if the Reynolds numbers are of the same order of magnitude and a turbulent boundary layer exists at the model base. Also presented is an analysis of jet duplication by use of a sting.
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Full-scale investigation of several jet-engine noise-reduction nozzles

Full-scale investigation of several jet-engine noise-reduction nozzles

Date: January 1, 1958
Creator: Coles, Willard D & Callaghan, Edmund E
Description: A number of noise-suppression nozzles were tested on full-scale engines. In general, these nozzles achieved noise reduction by the mixing interference of adjacent jets, that is, by using multiple-slot-nozzles. Several of the nozzles achieved reductions in sound power of approximately 5 decibels (nearly 70 percent) with small thrust losses (approx. 1 percent). The maximum sound-pressure level was reduced by as much as 18 decibels in particular frequency bands. Some of the nozzles showed considerable spatial asymmetry; that is, the sound field was not rotationally symmetrical. A method of calculating the limiting frequency effected by such nozzles is presented. Furthermore data are shown that appear to indicate that further reductions in sound power will not be easily achieved from nozzles using mixing interference as a means of noise suppression.
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