Solar powered aircraft

A cruciform wing structure for a solar powered aircraft is disclosed. Solar cells are mounted on horizontal wing surfaces. Wing surfaces with spanwise axis perpendicular to surfaces maintain these surfaces normal to the Sun's rays by allowing aircraft to be flown in a controlled pattern at a large bank angle. The solar airplane may be of conventional design with respect to fuselage, propeller and tail, or may be constructed around a core and driven by propeller mechanisms attached near the tips of the airfoils

No warmup crystal oscillator

During warmup, crystal oscillators often show a frequency offset as large as 1 part in 10 to the 5th power. If timing information is transferred to the oscillator and then the oscillator is allowed to warmup, a timing error greater than 1 millisecond will occur. For many applications, it is unsuitable to wait for the oscillator to warmup. For medium accuracy timing requirements where overall accuracies in the order of 1 millisecond are required, a no warmup crystal concept was developed. The concept utilizes two crystal oscillator, used sequentially to avoid using a crystal oscillator for timing much higher frequency accuracy once warmed up. The accuracy achieved with practical TCXOs at initial start over a range of temperatures is discussed. A second design utilizing two oven controlled oscillators is also discussed

Ground distance covered during airborne horizontal deceleration of an airplane

The distance an airplane floats with respect to the ground during deceleration at constant altitude is analyzed taking into account the effects of a constant wind. By use of suitable nondimensionalizing parameters, data applicable to all airplanes are presented by means of a single family of curves

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

Study of a control system to alleviate aircraft response to horizontal and vertical gusts

A study is made of the longitudinal response of a STOL airplane equipped with a vanecontrolled gust-alleviation system. Effects of various combinations of design parameters on the responses to horizontal and vertical gusts and to elevator inputs are presented. Almost complete gust alleviation may be obtained with this system when the center of gravity of the STOL airplane is at rearward locations, but pitch stability augmentation is required for satisfactory control characteristics

Altitude response of several airplanes during landing approach

The response in altitude and pitching velocity of the shuttle and of four other airplanes during the landing approach is compared. The effects of airplane type, pitch damping, center-of-gravity location, lift coefficient, and cockpit position are presented. The reasons for the differences observed and the effects of these differences on control characteristics are discussed

Research on blunt-faced entry configurations at angles of attack between 60 deg and 90 deg

Stability and control of blunt reentry configurations at angles of attack between 60 and 90 degree