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Technical Paper

Subsidy-Free VTOL Passenger Transport Operations

The short-to-medium haul VTOL passenger market growth has been limited by factors of equipment performance capability, equipment operating economics, and Federal constraint. ...In this study, the local and intercity markets susceptible to VTOL passenger movement are assessed, aircraft equipment requirements developed, and flight operational concepts described. ...It is indicated that a 40-50 place V/STOL passenger aircraft, operated VTOL normally, might provide competitive, subsidy-free transportation in the 1970 time period.
Technical Paper

VTOL Aircraft — Competitor or Assistant

This paper answers the question: Will the Vertical Takeoff and Landing (VTOL) commercial aircraft be a competitor or an assistant to conventional aircraft? VTOL of the type being studied by the Lockheed-California Co. are designed to compete with conventional commercial aircraft in short range operations. ...Northeast Corridor show that a fully developed VTOL system will assist the airlines by turning short haul operations from a losing to a profitable operation and by offering the passenger better service.
Technical Paper

Studies of VTOL Inlet Temperature Rise and Lift-Thrust

The results of a general VTOL airplane ground effect investigation for one to four lifting turbojets installed in the fuselage and wings are presented in this paper. ...The study provides information that will be very useful in the preliminary design layout and evaluation phase of VTOL development. The tests described here were conducted in Bell Aerosystems jet impingement test facility, which utilizes plant compressed air to provide model exhaust gas flows and a steam ejector to induce inlet flow equal to the exhaust flow.
Technical Paper

VTOL Aircraft Terminal Area Operations Research

Routine all-weather operation of VTOL aircraft in the terminal area environment is not possible at the present time because of the lack of knowledge required for satisfactory operation of this type of aircraft under IFR conditions. ...Specifically, many operating problems have been encountered during operation of VTOL aircraft in transition flight at low speed on an approach guidance system. This paper briefly summarizes these problems and then discusses related results that have been obtained from several flight research investigations.
Technical Paper

The Operational Potential of Manned, Ducted-Fan VTOL Vehicles

Compared to helicopters, the safety and operational advantages of ducted fan VTOL vehicles that do not rely on large, exposed rotors overhead seem promising. The alternative to the overhead rotor that naturally comes to mind is a smaller, enclosed rotor or multitude of rotors, sometimes referred to as ‘fans’, or, in combination with their enclosure, ‘ducted fans’. ...During the 50's and 60's, numerous experimental VTOL vehicles were developed, that relied on ducted fans as their main source of lifting power. ...The present paper discusses these issues, as well as design parameters that offer potential for reduced operational cost and increased profitability of future commercially operated ducted fan VTOL vehicles. The paper also describes briefly one candidate vehicle that has the potential to meet these requirements--Urban Aeronautics' X-Hawk--a tandem lifting fan, twin turbine powered, VTOL utility vehicle, featuring among other things a fly-by-wire, closed-loop vane control system (VCS), enabling it to operate in rough weather conditions and obstacle rich environments.
Technical Paper

Development of High-Performance Rotary-Wing VTOL Aircraft

This paper summarizes the programs for, and some of the results of, the Army's continuing effort in the development of high performance rotary wing VTOL aircraft. The objective of this continuing effort is to: 1. Increase the state of the art of rotary wing aircraft by providing advanced measured design data. 2.
Technical Paper

Control and Simulation of a Ducted Fan VTOL UAV

This paper describes a strategy to simulate a dynamic model of a vertical takeoff and landing (VTOL) unmanned aerial vehicle (UAV) in flight transition from vertical climb to horizontal flight.
Technical Paper

Helicopters and Propeller-Type VTOL Aircraft in the Light of Technologies

Pure and compound helicopters (including those with stoppable or stowable rotors) as well as propeller-type VTOLs are examined regarding their possibilities and limitations resulting from aerodynamics and structures. ...Retraction of the rotor improves aerodynamic cleanness to the levels of propeller type VTOL (tilt wing) aircraft, but weight penalties are the highest. Because of its superior performance, high level of agility and absence of fundamental aeroelastic limitations, the tilt wing type is seen to be outstanding for the combat type missions considered.
Technical Paper

Optimization of Military VTOL Secondary Power Systems

Military VTOL/VSTOL aircraft are required to operate in areas where it is impractical to provide ground support equipment to supply types of power needed for system checkout, emergency and standby power, and main engine starting. To provide this capability, the Secondary Power System must be considered on an integrated basis as a major aircraft subsystem which incorporates an auxiliary power unit (APU) that will provide an alternate source of power, in flight and on the ground, for aircraft hydraulics, pneumatic drives, APU starting, environmental control, main engine starting, electrical power generation, power transfer to accessory gearbox for shaft-driven accessories, plus the power distribution system to interconnect these components. This paper discusses the application of this integrated concept and the associated analyses of operating characteristics of major components. Appropriate interface and compatibility with the total air vehicle is illustrated.