The aerodynamic characteristics of three tapered airfoils tested in the variable density wind tunnel

This report contains the lift, drag, and moment characteristics of tapered Clark Y, Gottingen 393, and USA 45 airfoils as obtained from tests made in the Variable Density Wind Tunnel of the NACA. The results are given at both low and high Reynolds Numbers to show scale effect and to provide data for use in airplane design

The aerodynamic characteristics of airfoils at negative angles of attack

A number of airfoils, including 14 commonly used airfoils and 10 NACA airfoils, were tested through the negative angle-of-attack range in the NACA variable-density wind tunnel at a Reynolds Number of approximately 3,000,000. The tests were made to supply data to serve as a basis for the structural design of airplanes in the inverted flight condition. In order to make the results immediately available for this purpose they are presented herein in preliminary form, together with results of previous tests of the airfoils at positive angles of attack. An analysis of the results made to find the variation of the ratio of the maximum negative lift coefficient to the maximum positive lift coefficient led to the following conclusions: 1) For airfoils of a given thickness, the ratio -C(sub L max) / +C(sub L max) tends to decrease as the mean camber is increased. 2) For airfoils of a given mean camber, the ratio -C(sub L max) / +C(sub L max) tends to increase as the thickness increases

The experimental and calculated characteristics of 22 tapered wings

The experimental and calculated aerodynamic characteristics of 22 tapered wings are compared, using tests made in the variable-density wind tunnel. The wings had aspect ratios from 6 to 12 and taper ratios from 1:6:1 and 5:1. The compared characteristics are the pitching moment, the aerodynamic-center position, the lift-curve slope, the maximum lift coefficient, and the curves of drag. The method of obtaining the calculated values is based on the use of wing theory and experimentally determined airfoil section data. In general, the experimental and calculated characteristics are in sufficiently good agreement that the method may be applied to many problems of airplane design

Tests of three tapered airfoils based on the N.A.C.A. 2200, the N.A.C.A.-M6, and the Clark Y sections

Three tapered airfoils based on the N.A.C.A. 2200, the N.A.C.A.-M6, and the Clark Y sections were tested in the variable-density wind tunnel at a Reynolds Number of approximately 3,100,000. The models, which were of aspect ratio 6, had constant core center sections and rounded tips, and tapered in thickness from 18 percent at the roots to 9 percent at the tips. The aerodynamic characteristics are given by the usual dimensionless coefficients plotted for both positive and negative angles of attack and by effective profile-drag coefficients plotted against lift coefficients

Charts for determining the pitching moment of tapered wings with sweepback and twist

This report presents a convenient method for calculating the pitching-moment characteristics of tapered wings with sweepback and twist. The method is based on the fact that the pitching-moment characteristics of a wing may be specified by giving the value of the pitching moment at zero lift and the location of the axis about which the axis is constant. Data for calculating these characteristics are presented by curves which apply to wings having a linear distribution of twist along the span and which cover a large range of aspect ratios. The curves are given for wings having straight taper and distorted elliptical plan forms. The characteristics of wings of other shapes may be determined by interpolation

The aerodynamic characteristics of six commonly used Airfoils over a large range of positive and negative angles of attack

This paper presents the results of tests of six commonly used airfoils: the CYH, the N-22, the C-72, the Boeing 106, and the Gottingen 398. The lifts, drags, and pitching moments of the airfoils were measured through a large range of positive and negative angles of attack. The tests were made in the variable density wind tunnel of the National Advisory Committee for Aeronautics at a large Boeing 106, and the Gottingen 398 airfoils, the negative maximum lift coefficients were found to be approximately half the positive; but for the M-6 and the CYH, which have less effective values were, respectively, 0.8 and 0.6 of the positive values

A comparison of several tapered wings designed to avoid tip stalling

Optimum proportions of tapered wings were investigated by a method that involved a comparison of wings designed to be aerodynamically equal. The conditions of aerodynamic equality were equality in stalling speed, in induced drag at a low speed, and in the total drag at cruising speed. After the wings were adjusted to aerodynamic equivalence, the weights of the wings were calculated as a convenient method of indicating the optimum wing. The aerodynamic characteristics were calculated from wing theory and test data for the airfoil sections. Various combinations of washout, camber increase in the airfoil sections from the center to the tips, and sharp leading edges at the center were used to bring about the desired equivalence of maximum lift and center-stalling characteristics. In the calculation of the weights of the wings, a simple type of spar structure was assumed that permitted an integration across the span to determine the web and the flange weights. The covering and the remaining weight were taken in proportion to the wing area. The total weights showed the wings with camber and washout to have the lowest weights and indicated the minimum for wings with a taper ratio between 1/2 and 1/3

Pattern of protein synthesis in monkey cells infected by simian virus 40

Journal ArticleAfter infection of several permanent monkey cell lines by simian virus 40 (SV40), four additional protein bands can be detected by simple sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell extracts. These bands appear only after the onset of viral deoxyribonucleic acid (DNA) synthesis, and inhibitors of DNA synthesis prevent their appearance. Three of them correspond to three previously identified capsid components, VP1, VP2, and VP3. The fourth protein band, which does not correspond to a previously identified virion component, is induced by SV40 infection of CV-1 and BSC-1 cultures but not by infection of MA-134 cultures

Origin and destiny of adenovirus proteins

Journal ArticleLytic infection of human cells by adenovirus proceeds by a temporal expression of genes. Classically two phases have been defined: an early phase, which includes events occurring before the onset of DNA synthesis (8 hours), and a late phase, including events whose existence depends on the onset of DNA synthesis. During the late phase of infection, host cell macromolecular synthesis is progressively inhibited so that eventuallly only virus-specfic macromolecules are synthesized

Calculation of the aerodynamic characteristics of tapered wings with partial-span flaps

Factors derived from wing theory are presented. By means of these factors, the angle of zero lift, the lift-curve slope, the pitching moment, the aerodynamic-center position, and the induced drag of tapered wings with partial-span flaps may be calculated. The factors are given for wings of aspect ratios 6 and 10 , of taper ratios from 0.25 to 1.00, and with flaps of various length. An example is presented of the method of application of the factors. Fair agreement with experimental results is shown for two wings of different taper ratio having plain flaps of various spacing