A Preliminary Study of Airplane Performance

Flight tests were carried out at the Langley Field laboratory of the NACA, on several airplanes for the purpose of determining their relative performance with the same engine and the same propeller. The method used consisted in flying each airplane on a level course and measuring the airspeed for the whole range of engine revolutions. In general the results show that a small change in the wing section or the wing area has but a slight effect upon the performance, but changes in those parts which cause the structural resistance have a very important effect

Automated Mars surface sample return mission concepts for achievement of essential scientific objectives

Mission concepts were investigated for automated return to Earth of a Mars surface sample adequate for detailed analyses in scientific laboratories. The minimum sample mass sufficient to meet scientific requirements was determined. Types of materials and supporting measurements for essential analyses are reported. A baseline trajectory profile was selected for its low energy requirements and relatively simple implementation, and trajectory profile design data were developed for 1979 and 1981 launch opportunities. Efficient spacecraft systems were conceived by utilizing existing technology where possible. Systems concepts emphasized the 1979 launch opportunity, and the applicability of results to other opportunities was assessed. It was shown that the baseline missions (return through Mars parking orbit) and some comparison missions (return after sample transfer in Mars orbit) can be accomplished by using a single Titan III E/Centaur as the launch vehicle. All missions investigated can be accomplished by use of Space Shuttle/Centaur vehicles

Glaciated Rock Surfaces near Linn and near Quarry, Iowa, with a Table of the Bearings of Glacial Striae in Iowa

Linn is a junction of the Chicago, Rock Island and Pacific Railway, situated four miles northwest of Cedar Rapids. About one mile west of this station a rock cut, formerly used by the Chicago, Milwaukee and St. Paul Railway, scarps the bluffs bordering the Cedar River. At the extreme north end of the cut, 14 feet above the trackway, and about 75 feet above the level of the river, there is exposed by the retreat of a cover of yellow till and loess a surface of less than two feet square, developed on glaciated limestone belonging to the Acervularia davidsoni zone of the Cedar Valley stage of the Devonian. Although rubbed down to a fair degree of smoothness the rock was not planed level and retains something of an original convexity

A Reconsideration of the Age of Certain Outliers in Linn and Jackson Counties

At Bertram in Linn county and at Canton in Jackson county are found deposits of sandstone, shale and clay, called by courtesy outliers, though very limited in area and thickness, which carry Devonian fossils. Their importance lies in the fact that if their assignment to the Devonian by the writer in 1893 is correct, they imply a significant transgression of the Devonian sea over east central Iowa

Some Buried Pictured Rocks

This paper discussed the heavy beds of poikilitic sandstone found immediately underlying the Saint Peter sandstone of normal facies in several deep wells of eastern Iowa

General Formulae for Homozygosis

To find f (x) from the linear fractional relation

Economic Significance of Specific Export Promotion on Poverty Reduction and Inter- Industry Growth of Ethiopia

Micro simulated general equilibrium approach was used to analyze the economic significance of the current export promotion policy of Ethiopia. Simulation results, in general, indicated little achievements of economic growth and poverty reduction under selective export promotion. In this policy approach, only rural households were able to acquire higher income and lower poverty incidence. These achievements however were transmitted to small and big urban households when export promotion was assumed to be implemented across the board of all agricultural activities. Significant economic and inter-industrial growths were attained when the coffee industry was given equal policy treatments like other export agricultureSelective export promotion policy, computable general equilibrium, poverty reduction, foreign direct investment, Land Economics/Use, Resource /Energy Economics and Policy,

Pressure Distribution over the Rudder and Fin of an Airplane in Flight

This investigation was carried out by the National Advisory Committee for Aeronautics at the Langley Memorial Aeronautical Laboratory for the purpose of determining the loads which occur on the vertical tail surfaces in flight. The method consisted in measuring the pressures simultaneously at 28 points on the rudder and fin by means of a recording multiple manometer. The results show that the maximum load encountered in stunting was 7 pounds per square foot on the rudder and fin, and it is probable that this might rise to 10 pounds per square foot in a violent barrel roll; but in steady flight the average loads do not exceed 0.6 pound per square foot. The maximum load on the rudder and fin may occur at the same instant as the maximum load on the horizontal tail surfaces and the maximum normal acceleration. The torsional moment about the axis of the fuselage due to the rudder and fin may rise as high as 250 foot-pound. The results obtained from this investigation have a direct application to the design of the rudder, fin, and fuselage