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  Partner: UNT Libraries Government Documents Department
 Decade: 1940-1949
 Year: 1940
Variation in Velocity Profile with Change in Surface Roughness of Boundary

Variation in Velocity Profile with Change in Surface Roughness of Boundary

Date: September 1, 1940
Creator: Jacobs, W
Description: The present report deals with the variation of a turbulent velocity profile in flow from rough to smooth wall and vice versa. Expressions obtained for the shear-stress distribution with respect to the distance from the point of junction of the different roughnesses and from the wall distance, are utilized to ascertain the developing velocity distributions. Under simplified assumptions, the use of these formulas renders possible the integration of the motion equations for the shear stress. This calculation is carried out and compared with the experiments.
Contributing Partner: UNT Libraries Government Documents Department
Varieties of club wheat.

Varieties of club wheat.

Date: 1940
Creator: Clark, J. Allen (Jacob Allen), b. 1888.
Description: Describes several varieties of club wheats and where they grow in the United States.
Contributing Partner: UNT Libraries Government Documents Department
Varieties of durum wheat.

Varieties of durum wheat.

Date: 1940
Creator: Clark, J. Allen (Jacob Allen), b. 1888.
Description: Describes ten varieties of durum wheat grown in the United States.
Contributing Partner: UNT Libraries Government Documents Department
The Wheat Jointworm and Its Control

The Wheat Jointworm and Its Control

Date: 1940
Creator: Phillips, W. J. (William Jeter), 1879-1972
Description: Revised edition. "The wheat jointworm is a very small grub which lives in stems of wheat, feeding on the juices of the plant and causing a slight swelling or distortion of the stem above the joint. The egg from which it hatches is laid in the stem by an insect resembling a small black ant with wings. This insect attacks wheat only. The injury which it causes to wheat is very distinct from that caused by the Hessian fly, yet the effects caused by these two insects are often confused by farmers." -- p. 1-2. This bulletin gives a brief outline of the life cycle and the nature of the injury to the plant by the jointworm so that any farmer may readily recognize its work and be able to apply the measures of control herein recommended.
Contributing Partner: UNT Libraries Government Documents Department
Why potatoes run out.

Why potatoes run out.

Date: 1940
Creator: Schultz, E. S. (Eugene S.), 1884-
Description: Describes the types of diseases attacking potatoes, how to identify them, and how to treat the plants and seed potatoes in order to prevent the spread of disease.
Contributing Partner: UNT Libraries Government Documents Department
Wind-tunnel investigation of an NACA 23012 airfoil with two sizes of balanced split flap

Wind-tunnel investigation of an NACA 23012 airfoil with two sizes of balanced split flap

Date: November 1, 1940
Creator: Purser, Paul E
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Wind-tunnel investigation of an NACA 23030 airfoil with various arrangements of slotted flaps

Wind-tunnel investigation of an NACA 23030 airfoil with various arrangements of slotted flaps

Date: March 1, 1940
Creator: Recant, I G
Description: AN investigation was made of a large-chord NACA 23030 airfoil with a 40- and a 25.66 percent-chord slotted flap to determine the section aerodynamic characteristics of the airfoil affected by flap chord, slot shape, flap position, and flap deflection. The flap positions for maximum lift, the position for minimum drag at moderate and high lift coefficients, and the complete section aerodynamic characteristics of selected optimum arrangements are given. Envelope polar of various flap arrangements are included. The relative merits of slotted flaps of different chords on the NACA 23030 airfoil are discussed, and a comparison is made of each flap size with a corresponding flap size on the NACA 23021 and 23012 airfoils. The lowest profile drags at moderate lift coefficients were obtained with an easy entrance to the slot. The 25.66-percent-chord slotted flap gave lower drag than the 40-percent-chord flap for lift coefficients less than 1.8, but the 40-percent-chord flap gave considerably lower drag for lift coefficients. The drag coefficients at moderate and high lift coefficients were greater with both sizes of flap on the NACA 23030 airfoil than on either the NACA 23021 or the NACA 23012 airfoil. The maximum lift coefficient for the deflections tested with either ...
Contributing Partner: UNT Libraries Government Documents Department
Wind tunnel investigation of fuselage stability in yaw with various arrangements of fins

Wind tunnel investigation of fuselage stability in yaw with various arrangements of fins

Date: November 1, 1940
Creator: Hoggard, H Page, Jr
Description: An investigation was made in the 7-by-10 foot wind tunnel to determine the effects of dorsal-type fins and various arrangements of fins on the aerodynamic characteristics of a streamline circular fuselage. Comparative plots of the aerodynamic characteristics of the fuselage alone and the fuselage with various fin arrangements are given to show their effects on coefficients of yawing moment, drag, and lateral force. Results are also given for one case in which a rear fin on a circular fuselage was faired with modeling clay to obtain a fuselage shape with the same side elevation as the fuselage with the unfaired fin but with an elliptical cross section over the rearward portion of the fuselage. The results indicated that fin area to the rear of the center of gravity of the fuselage was beneficial in reducing the magnitude of the unstable yawing moments at large angles of yaw; whereas, fin area forward of the center of gravity was harmful. The dorsal-type fin was more effective for increasing the yawing stability of the fuselage than was a smoothly faired rearward portion with the same side elevation as the fuselage with the unfaired dorsal type fin. The minimum drag coefficient and the slope ...
Contributing Partner: UNT Libraries Government Documents Department
Wind-Tunnel Investigation of Rectangular Air-Duct Entrances in the Leading Edge of an NACA 23018 Wing, Special Report

Wind-Tunnel Investigation of Rectangular Air-Duct Entrances in the Leading Edge of an NACA 23018 Wing, Special Report

Date: September 1, 1940
Creator: Biermann, David
Description: A preliminary investigation of a number of duct entrances of rectangular shape installed in the leading edge of a wing was conducted in the NACA 20-foot tunnel to determine the external drag, the available pressure, the critical Mach numbers, and the effect on the maximum lift. The results showed that the most satisfactory entrances, which had practically no effect on the wing characteristics, had their lips approximately in the vertical plane of the leading edge of the wing. This requirement necessitated extending the lips outside the wing contour for all except the small entrances. Full dynamic pressure was found to be available over a fairly wide range of angle of attack. The critical Mach number for a small entrance was calculated to be as high as that for the plain wing but was slightly lower for the larger entrances tested.
Contributing Partner: UNT Libraries Government Documents Department
Wind-Tunnel Investigation of the Lift Characteristics of an NACA 27-212 Airfoil Equipped with Two Types of Flap, Special Report

Wind-Tunnel Investigation of the Lift Characteristics of an NACA 27-212 Airfoil Equipped with Two Types of Flap, Special Report

Date: September 1, 1940
Creator: Swanson, Robert S.
Description: An investigation has been made in the NACA 7- by 10-foot wind tunnel of a large chord NACA 27-212 airfoil with a 20% chord split flap and with two arrangements of a 25.66% chord slotted flap to determine the section lift characteristics as affected by flap deflection for the split flap and as affected by flap deflection, flap position, and slot shape for the slotted flap. For the two arrangements of the slotted flap, the flap positions for maximum section lift are given. Comparable data on the NACA 23012 airfoil equipped with similar flaps are also given. On the basis of maximum section lift coefficient, the slotted flap with an easy slot entry was slightly better than either the split flap or the slotted flap with a sharp slot entry. With both types of flap the decrease in the angle of attack, for maximum section lift coefficient, with flap deflection is large for the NACA 27-212 airfoil as compared with the NACA 23012 airfoil. Also with both flaps, the maximum section lift coefficient obtained with flaps is much lower for the NACA 27-212 airfoil than for the NACA 23012 airfoil.
Contributing Partner: UNT Libraries Government Documents Department