"If the low-powered airplane is to be used advantageously by private individuals, the most important consideration is a smaller fuel consumption and, hence, a lower engine power. From experiments with gliders, it appears entirely possible, by utilizing ascending winds (on the weather side of mountains and those generated by the heat of the sun) and by employing engine flight intermittently, as required to fly long distances over land" (p. 1).

Similarities in the study of aviation accidents in different countries are made as well as statistics on the causes of those accidents.

Report presenting an analysis of the title coefficient as used in Kahn's formula for the ceiling.

The report discussing single and two-seater airplanes as well as larger airplanes.

'Experiments similar to those carried out with the A.E.G (Allgemeine Elektrizitats-Gesellschaft) were made in the small wind tunnel of the Gottingen laboratory on a model of the D.F.W. airplane T-29. Three series of tests were carried out on the model with a velocity head (or dynamic pressure) of 5 kg/sq m (1.02 lb/sq ft), during which one of the movable surfaces was deflected at various angles, while both the others were retained in their central positions. Of special interest among the results of the tests is the different run of the elevating moments" (p. 1).

Note presenting an investigation of curvilinear flight, which is defined as steady horizontal flight in a circle in which no side slip occurs. The investigation occurred under very specific circumstances and rests on two basic assumptions, which are that the airplane lies correctly in the turn so the resultant of gravity and centrifugal force falls in the plane of symmetry and that the airplane must lie in the turn so that the axis coincides with the direction of motion.

"Dihedral and sweep back can properly be compared only to the extent to which their action is similar in a side slip. In general the rolling moments due to side slip are about three to six times greater for a given dihedral angle than for an equal angle of sweep back" (p. 1).

From Summary: "This report contains a brief study of the variation of engine power with temperature and pressure. The variation of propeller efficiency in standard atmosphere is obtained from the general efficiency curve which is developed in NACA report no. 168. The variation of both power available and power required are then determined and curves plotted, so that the absolute ceiling may be read directly from any known sea-level value of the ratio of power available to power required."

This report contains the derivation and the verification of formulae for predicting the speed range ratio, the initial rate of climb, and the absolute ceiling of an airplane. Curves used in the computation are given in NACA-TR-171. Standard formulae for service ceiling, time of climb, cruising range, and endurance are also given in the conventional forms.

This report is an extension of NACA-TR-168 and has been prepared for the National Advisory Committee for Aeronautics to show the relative values of various direct and geared drives. It is well known that in general a geared-down propeller has higher efficiency than a direct-drive propeller, but the literature on this subject does not present the data in such form that the aeronautical engineer can readily visualize the effect of gearing. This report has been prepared to show the actual net gain or loss in maximum efficiency due to the use of various modifications of the conventional two-bladed, direct-drive propeller. (author).