Report presenting a description of the design of the Blériot-Spad 91 airplane. This aircraft has announced a speed of 270 km per hour at 4000 m. It is of all metal construction.

Equipped with a Wright Whirlwind 200-230 H.P. Engine, the Universal can be configured with floats or wheels and seats 4-6 passengers. Details of the wings, power plant, cowling, tanks and fuel system, vision, cockpit and controls, cabin arrangements, landing gear, float gear, skis, tail skid, tail surfaces, finish, characteristics, drawings, and photographs are provided.

Report of the annual conference on weights and measures, hosted by the U.S. National Bureau of Standards in Washington D.C. It includes conference proceedings, a list of attendees, information about committees and officers, and other reports or commentaries discussed at the meetings.

The tests described in this report constitute a preliminary investigation of airfoil boundary layer control, as carried out in the atmospheric wind tunnel of the Langley Memorial Aeronautical Laboratory, from February to August, 1927. Tests were made on a U.S.A. 27 airfoil section with various slot shapes and combinations, and at various amounts of pressure or suction on the slots. The lift of airfoils can be increased by removing or by accelerating the boundary layer. Removing the boundary layer by suction is more economical than to accelerate it by jet action. Gauze-covered suction slots apparently give the best results. When not in operation, all suction slots tested had a detrimental effect upon the aerodynamic characteristics of the airfoil which was not apparent with the backward-opening pressure slots. Thick, blunt-nose airfoils would seem to give best results with boundary layer control.

Tests were conducted to investigate the possibility of a serious accident arising from unintentional contact with the water in substantially horizontal flight at high speed. Referring to vector diagrams on Figure 2, it will be seen that a very dangerous condition may arise if the float be allowed to come in contact with the water at high speeds as, for example, when flying at high speed just above the water. The initial diving moment due to suction and drag combined may be great enough to cause the seaplane to nose under before the pilot is able to control the motion.

"A peculiar phenomena in seaplane landing is observed and reported. The seaplane having executed a normal fast landing at low incidence, a forward movement of the control stick effected an unusual condition in that the seaplane left the water suddenly in an abnormal attitude. The observations describing this phenomena are offered as a warning against possible accident and as a conjectural cause of seaplane landing accidents of a certain kind" (p. 1).

Describes various species of insects that target peach crops in the southern United States, and methods of control.

This report describes the leading crankless engine types, which have appeared in recent years. These types include: the Mitchell crankless motor car engine and the German Michel engine.

This report presents a survey of the latest German giant airplane projects. A description of the physical form of the airplanes, their performance, and some possible applications are provided.

Circular presenting a description of the Parnall Imp, which is a new British light airplane that lacks any wire bracing, has an all-wood construction, and has general weatherproof qualities. Results regarding wings, fuselage, landing gear, engine, cockpit, characteristics, drawings, and photographs are provided.

The object of the present treatise is to examine the present status of aerial safety and to review the efforts of various commissions to promote safety.

This report focuses on structural strength and engine design in building and designing safer aircraft.

This report presents the first part of a two part study made under this title. In this part the symmetrical inviscid flow about an empirical strut of high service merit is found by both the Rankine and the Joukowsky methods. The results can be made to agree as closely as wished. Theoretical stream surfaces as well as surfaces of constant speed and pressure in the fluid about the strut are found. The surface pressure computed from the two theories agrees well with the measured pressure on the fore part of the model but not so well on the after part. From the theoretical flow speed the surface friction is computed by an empirical formula. The drag integrated from the friction and measured pressure closely equals the whole measured drag. As the pressure drag and the whole drag are accurately determined, the friction formula also appears trustworthy for such fair shapes. (author).

The laws of comparison of dynamically similar fluid motions are derived by three different methods based on the same principle and yielding the same or equivalent formulas. This report outlines the three current methods of comparing dynamically similar motions, more especially of fluids, initiated respectively by Newton, Stokes (or Helmholtz), and Rayleigh. These three methods, viz., the integral, the differential, and the dimensional, are enough alike to be studied profitably together. They are treated in succession then compared. (author).

"The rate of change in power of aircraft engines with altitude has been the subject of considerable discussion. Only a small amount of data from direct measurements of the power delivered by airplane engines during flight, however, has been published. This report presents the results of direct measurements of the power delivered by a Liberty 12 airplane engine taken with a hub dynamometer at standard altitudes from zero to 13,000 feet. Six flights were made with the engine installed in a modified DH-4 airplane" (p. 323).

"This report covers the results of an investigation carried on at the Bureau of Standards under a research authorization from, and with the financial assistance of, the National Advisory Committee for Aeronautics. The choice of a damping liquid for aircraft instruments is difficult owing to the range of temperature at which aircraft operate. Temperature changes affect the viscosity tremendously. The investigation was undertaken with the object of finding liquids of various viscosities otherwise suitable which had a minimum change in viscosity with temperature" (p. 405).

"The advantages to be gained from braking have not been ignored, and in the search for a suitable method many schemes have been suggested and tried. Some of the methods discussed in this paper include: 1) increasing the height of the landing gear; 2) air brakes of various forms; 3) sprags on tail skid and axle; and 4) wheel brakes. This report focuses on the design of wheel brakes and wheel brake controls" (p. 1).

Annual report submitted by the Boy Scouts of America to Congress describing highlights from 1927, activities, ideals, organizational leadership, and other information about scouting programs.