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FOR preliminary design work on transport airplanes, a graphical method is outlined for determining the effect which changes in a set of chosen major design variables will have on the airplane's ability to meet a given set of specifications and regulations. Engines, propellers, and wing geometry are selected. Then for each condition laid down as a specification or regulation, a limiting curve of maximum weight allowed by the condition is plotted as a function of wing area. These curves are developed from basic data and standard equations. If it is possible to meet all the conditions, the limiting curves - when plotted together on one graph - will enclose an area on the “allowable” side of all curves.

FLYING at altitude intensifies most problems, simplifies some, the author shows. Increasing operating altitude from 25,000 ft to well into the stratosphere lowers temperature more than 50 F, and reduces pressure to one-fifth the sea-level value. This complicates structural problems. It affects the hydraulic and control systems, electrical systems, cooling, and air conditioning, and increases the danger from failure of any of these essentials. Gusts and turbulence, on the other hand, are lessened by flying high. The author charts the extent of each of the problems, and shows how altitude economy gains make solutions imperative.

Because of the rapid growth of air travel, both cargo and passenger, the payload capacity required for future transport aircraft is too great to be accommodated by fuselages of conventional configuration (that is, single-deck, single-aisle, up to 6 seats abreast). Fuselage design philosophy was therefore re-evaluated in a recent Douglas study, and this paper reviews some of the features of that study. Factors affecting fuselage design are outlined and trends are discussed. It is concluded that the forthcoming wide, single-deck fuselage, seating up to 10 abreast, will have a potential capacity of about 550 passengers. For larger capacities, the greater efficiency of multi-deck fuselages over that of the single-deck becomes increasingly apparent on a per-passenger basis. The use of multi-deck fuselages, however, will raise new problems-particularly those of airport terminal design and passenger evacuation-but these should not prove insurmountable.

This paper presents additional information of a theoretical nature and a synoptic case study concerning the nature of the generation of Clear Air Turbulence. The hypothesis in this paper is that (a) Shear is generated rapidly in a specific region of the atmosphere. (b) The shear reaches a critical value and the flow field becomes turbulent. (c) The turbulent flow field, in the form of a cell or eddy, is carried away from the source region and gradually decays. The theory on which the prediction of shear is based is developed on a nonlinear basis to show that if convection of vorticity is neglected, the vertical component of the vorticity depends quadratically with time on the solenoids of temperature and divergence of velocity, plus another smaller term. Thus the horizontal shear of the velocity may be expected in certain large scale synoptic situations to grow nonlinearly. Synoptic analysis has been made by computer program of a well-known case of CAT: April, 1962.

The S-IV and S-IVB stages for the Saturn vehicles were designed to utilize the high specific impulse of the liquid hydrogen - liquid oxygen propulsion system. The use of liquid hydrogen presented special structural problems that led to the development of the reinforced foam internal insulation and the sandwiched honeycomb common bulkhead. The major design problem in each case was the high thermal stress resulting from the steep thermal gradient across the depth of the structure. For the extreme temperatures involved the thermal stresses were very high and were dominant factors in establishing the designs.