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Technical Paper

How High Should We Fly?

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.
Technical Paper


THIS paper describes the operational and performance characteristics which will make the DC-8 jet transport capable of economical operation over both long- and short-range routes of reasonably high traffic density. It is shown, for example, that the effects of operation with one or two engines inoperative, the effect of high ambient air temperatures, and effects of flying at nonoptimum altitudes, while different from reciprocating-engine aircraft, will permit easy integration of the jet transport into existing airline operations. Furthermore, the jet transports will have such short take-off distances when carrying fuel sufficient for short and moderate ranges that most existing airport runways, now used for DC-6B and DC-7 operation, are of sufficient length for jet-transport operation.
Technical Paper


THIS PAPER presents the development of the DC-8 suppressor and thrust brake unit from initial test work through the final design. The selection of the production unit was based on a wide background of test work using both model and full-scale facilities. On the basis of this work, the configuration selected for production consisted of a fixed, corrugated, suppressing nozzle with a retractable ejector. A target-type thrust brake, mounted in the ejector, was chosen for the thrust brake production unit. Approximately 12-db suppression and 44% reverse thrust are provided by the unit. The ejector is hydraulically operated and the thrust brake air actuated. Both actuation systems obtain power from the aircraft systems which provides for operation during engine-out conditions. Alternate methods of actuation are provided in case of a primary system failure.
Technical Paper

A Theory of Generation of Clear Air Turbulence

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.
Technical Paper

Recommended Practices for Use in the Measurement and Evaluation of Aircraft Neighborhood Noise Levels

SAE Committee A-21, Aircraft Exterior Noise Measurements, was formed in 1961 to develop recommended practices for use in the evaluation of aircraft noise as it relates to airport neighborhood annoyance problems. The general areas of interest to the committee include the measurement, propagation, prediction and subjective rating of aircraft noise. This paper discusses the evaluation of aircraft neighborhood noise levels and describes the subjective measures by which comparisons can be made. Included in the discussion are the recommended practices adopted by SAE and those that are being studied by Committee A-21.
Technical Paper

Fuselage Configuration Studies

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.
Technical Paper

GMs — Aircraft, Seacraft, or Groundcraft

This paper explains the different applications of ground effect machines and why they should be built in aircraft manufacturing companies. The importance of L/D and initial cost is shown, and also the levels which have to be achieved in order to compete with ships. The main advantage of ground effect machines, the capability to move fast over water, and the potential market for such vehicles are pointed out. Assault operation is mentioned as well as operation over land, mostly swamps.