The Democratization of Invention in the American South: Antebellum and Post Bellum Technology Markets in the United States

Patenting expanded rapidly across the post bellum South as its transportation network filled in and city growth extended markets. This was consistent with Sokoloff and Khan (1990), who demonstrated the elastic supply of patentable ideas in early America. Successful innovation required that inventors could or did sell their property rights through "assignment" to those who commercialized new technology. The assignment characteristics of 1912 southern patents were examined. Southern "border" state patents had a higher rate of marketable assignments than those issued to residents in the Deep South. Greater commercialization of patents in border state cities accounted for most of this difference.post-bellum South, invention, patents

Loads implications of gust-alleviation systems

A brief review is presented of the basic methods of gust alleviation. Some results obtained in flight tests of a gust-alleviation system are included

Analysis of Effects of Interceptor Roll Performance and Maneuverability on Success of Collision-Course Attack

An attempt has been made to determine the importance of rolling performance and other factors in the design of an interceptor which uses collision-course tactics. A graphical method is presented for simple visualization of attack situations. By means of diagrams showing vectoring limits, that is, the ranges of interceptor position and heading from which attacks may be successfully completed, the relative importance of rolling performance and normal-acceleration capability in determining the success of attacks is illustrated. The results indicate that the reduction in success of attacks due to reduced rolling performance (within the limits generally acceptable from the pilots' standpoint) is very small, whereas the benefits due to substantially increasing the normal-acceleration capability are large. Additional brief analyses show that the optimum speed for initiating a head-on attack is often that corresponding to the upper left-hand corner of the V-g diagram. In these cases, increasing speed beyond this point for given values of normal acceleration and radar range rapidly decreases the width of the region from which successful attacks can be initiated. On the other hand, if the radar range is increased with a variation somewhere between the first and second power of the interceptor speed, the linear dimensions of the region from which successful attacks can be initiated vary as the square of the interceptor speed

Application of spring tabs to elevator controls

Equations are presented for calculating the stick-force characteristics obtained with a spring-tab type of elevator control. The main problems encountered in the design of a satisfactory elevator spring tab are to provide stick forces in the desired range, to maintain the force per g sufficiently constant throughout the speed range, to avoid undesirable "feel" of the control in ground handling or in flight at low airspeeds, and to prevent flutter. Examples are presented to show the design features of spring tabs required to solve these problems for airplanes of various sizes

Determination of the Pressure Drag of Airfoils by Integration of Surface Pressures

A study was conducted of the causes of pressure drag of subsonic airfoils. In a previous paper by the author, the pressure drag is obtained by calculating the total drag from the momentum defect in the boundary layer at the trailing edge and subtracting the friction drag obtained from integration of surface friction along the chord. Herein, the pressure drag is obtained by integrating the streamwise components of surface pressure around the airfoil. Studies were made to verify the accuracy of the integration procedure. The values of pressure drag were much smaller than those obtained by the previous method. This lack of agreement is attributed to the difficulty of calculating boundary layer conditions in the vicinity of the trailing edge and to the extreme sensitivity of the circulation and lift to the trailing edge conditions. The results of these studies are compared with those of previous investigations