Circular describing the S.P.C.A. 40 T, which is a commercial all-metal cantilever airplane that was guided by the two essential requirements of economy and safety in its design. Details of the design, power, test results, fuel tanks, characteristics, performances, drawings, and photographs are provided.

Report presenting an analysis of data for turbulent boundary layers along wings and bodies of various shapes in order to determine the fundamental variables that control the development of turbulent boundary layers. Results indicate that the type of velocity distribution in the boundary layer could be expressed in terms of a single parameter.

Circular describing the D.H. 83 "Fox Moth", which is a three-passenger light cabin biplane that is considered a commercial airplane despite taking many of its components from the company's existing two-seat touring and training light airplanes. A description of these components, design, flight characteristics, performance, drawings, and photographs are provided.

Built by the 'Czecho-Slovakian' aircraft factory, AVIA, the B.H. 21, has a top speed of 250 MPH, and carries 120 kg of gasoline and 20 kg of oil, giving it a radius of action of 600-650 km. It is equipped with a Hispano-Suiza engine capable of 300 HP. Details of the design, structure, wings, stabilizer, fuselage, controls, fuel tanks, landing gear, tail, characteristics, performances, drawings, and photographs are provided.

Circular presenting a description of the Hanriot H 431, which was designed to meet the requirements of the French War Ministry for general purpose airplanes. Details are provided for the design, flying qualities, and improvements over other aircraft designs.

Circular presenting the Valetta, which is a twin-float seaplane and flying boat with a power plant comprised of three Bristol "Jupiter" XI F geared engines. A description of the design, characteristics, performance, blueprints, and photographs are provided.

Circular presenting a description of the Baynes Bee, which is a light two-seat high-wing monoplane. Details of its unique qualities, design, components, flying qualities, drawings, and photographs are provided.

Report presenting tests on an exhaust-gas turbine with four separate nozzle boxes each covering a 90 degree arc of the nozzle diaphragm and each connected to a pair of adjacent cylinders in a Pratt & Whitney R-1340-12 nine-cylinder radial engine. Results regarding the power output of the engine and turbine, effect of the turbine on engine power, turbine power output and speed characteristics, mean turbine efficiency, effect of the blowdown turbine on exhaust-gas temperature, and condition of the blowdown turbine after tests are provided.

Circular presenting a description of the Nieuport-Delage 590 three-engine colonial cantilever monoplane, which meets the requirements of the program established by the French Government. Information is provided regarding the design, construction, and instruments are provided.

Circular presenting a description of the Bleriot 110 which is a long-distance airplane mainly distinguished by its fineness and lightness. Details of the fuselage, shape, wing, and power plant are provided.

Circular presenting a description of the Breguet 390 T, which is a three-engine all-metal transport sesquiplane with the same structural principles as the Breguet military airplane. This aircraft design replaces a girder fuselage with an orthodox rectangular fuselage with accommodations for ten passengers and baggage. Details of the design, components, flying qualities, drawings, and photographs are provided.

Circular describing the Farman F.300 airplane, which is a high-wing semicantilever monoplane. Details of the wings, engine, equipment, safety, characteristics, performance, drawings, and photographs are provided.

Circular describing the Saunders Cutty Sark commercial seaplane, which is a high-wing monoplane flying boat. Details regarding the power unit, engines, fuel system, components, characteristics, drawings, and photographs are provided.

Circular presenting a description of the Short "Empire" flying boat, which is an all-metal, four-engine, cantilever monoplane with a two-step hull.

Circular describing the Armstrong-Whitworth "Starling", which is a single seat fighter that can be used for day fighting and night fighting. Details of the wings, wing bracing, lift characteristics, construction, internal components, characteristics, drawings, and photographs are provided.

Circular describing the Dewoitine D.332, which is a commercial three-engine all-metal low-wing monoplane form France. Details of the construction history, wing, fuselage, power plant, landing gear, characteristics, performance, drawings, and photographs are provided.

Circular presenting a description of the Westland IV, which is a high-wing monoplane with strut bracing, two outboard engines, a fairly large fuselage that provides comfortable cabin accommodation, and wide-track landing gear. Details of the design, flight characteristics, blueprints, and photographs are provided.

Circular describing the Avro Gosport 504 R, which is a new training airplane that is lighter than other Avro training airplanes but is strong enough to withstand rough handling that may be encountered in training. Details of the fuselage, construction, ailerons, tail, struts, landing gear, fuel tanks, performance, characteristics, and photographs are provided.

The Partridge is a tractor biplane of orthodox design. It has a single supercharged Jupiter VII engine.

Circular detailing the Glouster "Gambet", which is a new single-seat fighter for use from aircraft carriers. A description of the design, components, characteristics, photographs, and drawings are provided.

Circular presenting a description of the Boulton and Paul P.64 high-performance mail-carrier. It is a two-engine tractor biplane that has been designed to give the specified normal speed with each engine throttled down to approximately half its output. Details of the landing gear, structural features, pilots' compartment, accommodation for mails, controls, power plant, and some flying qualities are provided.

The Ca 97 is constructed with wings half overhung, a large fuselage, all metal construction, and can be configured with 1 to 3 engines.

Circular describing the Avia 51 commercial airplane, which is a Czechoslovakian cantilever high-wing monoplane with a fairly orthodox design. Details of the performance, construction, wing, ailerons, fuselage, landing gear, engines, characteristics, drawings, and photographs are provided.

Circular describing the Avro 631 training airplane, which is a British two-seat light biplane that is meant to be affordable and small. Details regarding the wings, fuselage, tail unit, landing gear, power plant, accommodation, characteristics, performance, drawings, and photographs are provided.