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The purpose of this paper is to study the conceptual design and optimisation of a compound gyroplane. A study of a compound gyroplane configuration and its characteristics was performed to develop a sizing program.

The vertical takeoff and landing capabilities of a helicopter are particularly important. The need for efficient hover and the effectiveness of forward flight in the helicopter can cause conflicts within the design process. The designers usually wish to increase the helicopter's maximum forward speed. Recently, the compound aircraft is one of the concepts considered for the purpose of expanding the flight envelope of rotorcraft. The study of the compound gyroplane showed its advance capabilities for this purpose. Understanding its characteristics, a number of calculations are conducted to implement a sizing program for compound gyroplanes based on the conventional helicopter sizing process.

The results of the sizing program were validated using existing aircraft data such as the Challis Heliplane, Carter Copter, FB‐1 Gyrodyne, and Jet Gyrodyne. The program is appropriate to size a compound gyroplane at the conceptual design phase. An optimisation study was also performed to enhance sizing results. The compromise between the rotor lift sharing factor and the ratio of the wing span (Bw) to rotor diameter (D) was solved by choosing the total gross weight (TOGW) as the objective function, while the design variables are compromising factors. The optimum results showed that the TOGW of all four kinds of compound gyroplanes was considerably reduced.

A conceptual sizing program for unconventional compound aircraft was developed. The study showed that an optimum design process is necessary to enhance the sizing results.

THIS new official glossary of American aeronautical terms replaces Report No. 240, which was published in 1926. It is a fortunate coincidence that it should appear so soon after the revised British Standard Glossary of Aeronautical terms, which was reviewed in AIRCRAFT ENGINEERING, Vol. V, August 1933, p. 183. Much development has, of course, taken place since the last edition, and the time for a revision of terminological practice was certainly due. Actually, the period of the revision of the two lists overlapped to some extent and an early proof of the new British glossary was sent to the American committee as soon as it was known in England that it was being reconstituted. There is evidence that use was made of this, as in some instances where the use of words is identical in the two countries the language used in the definitions is very similar.

Aircraft structures are built up of previously constructed members comprising a skin part and stress‐carrying structure, the structures being completed by interattaching the members in a surface containing the neutral axis of the completed structure. In one form, a wing is built up of components comprising spar parts 1A, 3A, ribs 4A, 4, 4B, and metal skin 5. The appropriate spars are butt‐jointed together and the structure is completed by a nose fairing 8 which may be secured by wire pins 9. A tank 10 may be housed in the wing. In a modification, the skin is supported by a corrugated sheet attached to a capping strip secured to brackets which are connected to the lap‐jointed spars. In a further modification, the spar is formed by securing flange portions, which may be built up of laminations, to a lightened web. A wing flap may be hinged to the trailing edge of the wing. A fuselage may similarly be built up of components 71, 72 butt jointed as at 73. In a modification of this form, a bomb 88 may be housed in the fuselage, hinged doors 89 being provided. A tapering fuselage may be built from blanks of different dimensions pressed to shape by a single set of tools. The fuselage may be built up of quadrantal portions, and decks and floorings may be incorporated in the stiffening members. A seaplane float may be constructed in a similar manner.

This work represents a study of the deformation of the membranes used in the construction of aneroid capsules under the influence of a difference in pressure between the two faces and seeks to determine the influence of the various factors which concern their construction, i.e., thickness of metal, the width and depth of the corrugations and the diameter of the membrane. The influence exerted by the thickness of the metal and the diameter are self evident but the other two factors have a much more complex effect.