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Technical Paper

V/STOL Performance, Stability and Control Requirements from an Operations Analysis Viewpoint

This paper considers performance, stability, and control requirements in terms of their influence on the mission effectiveness and program cost of V/STOL weapon systems; hence, their cost-effectiveness. Performance, stability, and control are among the characteristics that determine the size, weight, and complexity of an aircraft, and ultimately, therefore, its cost. These factors also affect mission effectiveness by their influence upon the availability and survivability of the aircraft and accuracy of its weapons. “Operations Analysis” techniques are required for combining these interrelated factors to evaluate cost-effectiveness. An application is presented for an armed tactical support V/STOL aircraft. Three types are compared: pure helicopter, compound helicopter, and tilt wing.
Technical Paper

The World-Wide Search and Retrieval Problem - Factors Involved in the Selection of a Rescue/Retrieval Aircraft

Future retrieval requirements for aircraft, missiles, and returning space vehicles have been matched against possible future retrieval systems to determine the most effective and flexible solution in terms of technical feasibility and economics. It has been found that primary vehicle requirements can be met using existing transport aircraft and a VTOL, possibly a retrieval adaptation of the planned Tri-Service VTOL transport. Great economies can be realized if “line” techniques for pick-up of objects by conventional aircraft in flight can be further developed. Long range amphibious aircraft and surface ships, some of the latter with hydrofoil capability, would provide the necessary versatility to meet the variety of future retrieval requirements.
Technical Paper

Ideas, Integrated Design and Analysis System

IDEAS (Integrated Design and Analysis System) is a new approach directed toward the rapid definition of design loading conditions and internal structural element loads needed for the sizing and analysis of the primary structure of an entire aircraft. It is an integrated collection of many different kinds of computer programs and formalized calculations which are performed in particular sequence. Complete integration is of prime significance. Output data from any one kind of computer program is in the precise format required as input for subsequently used programs of the system. System capability is sufficiently broad to provide state-of-the-art analysis procedures for both variable-sweep supersonic aircraft and fixed-wing subsonic aircraft. It treats all applicable flight maneuvers, landing and catapult conditions, taxiing conditions, gust and flutter analyses.
Technical Paper

Gulfstream II Aerodynamic Design

The Gulfstream II business jet is a low wing aircraft of moderate sweep featuring a T-tail arrangement and two aft-mounted turbofan engines. The paper outlines aerodynamic development of the configuration and control system, highlighting significant design decisions and aerodynamic characteristics with appropriate experimental data including force, pressure, and flow visualization results. Aerodynamic design considerations included: wing optimization to meet the requirements of high and low speed performance and a pitch-down stall break at all flight conditions while providing adequate fuel volume; nacelle-pylon-wing relationship for optimum drag, engine characteristics, and airplane balance; and an empennage arrangement providing satisfactory stability and control at all conceivable flight conditions. The Gulfstream II configuration provides strong aerodynamic resistance to inadvertent secondary stall entry and more than adequate recovery capability.
Technical Paper

Optimizing Exhaust — Nozzle/Airframe Thrust Minus Drag

This paper discusses exhaust nozzle performance, the interaction of exhaust nozzle and airframe, and the need for considering the effect of interactions when estimating overall performance. New performance parameters such as interference drag and equivalent thrust are introduced to account for these interactions. These parameters can be used to provide a consistent semi-empirical approach to optimizing exhaust nozzle/airframe performance and to measure achievements during the optimization process. Emphirical correlations based on the new parameters are displayed for several exhaust nozzle/aircraft combinations.
Technical Paper

Design and Fabrication of a Pressurized Boron Composite Wing Box

The paper describes the development of the design and the fabrication procedures required to replace an existing aluminum section of wing structure with a part made of boron-epoxy. The wing box extension was selected as a significant aircraft demonstration component for boron-epoxy because it incorporates many of the problems associated with aircraft structures such as access covers, control surface mountings, contoured surfaces, and fuel pressurization; and because of the variety of loads and environmental conditions involved. Although the existing aluminum design is unpressurized, the demonstration component has been designed to include a pressurized cell in order to demonstrate the feasibility of building an integral fuel tank. Representative test data and specimens, design allowable philosophy used, and specific weight-strength comparisons with typical aircraft materials are presented. Process techniques used in boron laminate fabrication are discussed.