Quiet Short-Haul Research Aircraft Research Articles

Flight evaluation of pursuit displays for precision approach of powered-lift aircraft

Flight experiments with NASA Ames Research Center's quiet short-haul research aircraft evaluated the influence of pursuit displays on the ability of pilots to execute precision-instrument flight operations in the terminal area, particularly approaches to and landings on a short runway. The aircraft is a powered-lift, short-takeoff and landing configuration equipped with a modern digital fly-by-wire flight control system, a head-up display, and a color head-down display that make it possible to investigate control and display concepts for full-envelope, powered-lift operations. Flight-path-oriented displays that provide status and command information in a format with minimal clutter were investigated. The pilots could fly the aircraft with the precision associated with flight-director guidance and with a high degree of situation awareness. The primary benefits of this display concept were realized when the pilot was required to execute a complex transition and approach under instrument conditions and in the presence of a wide range of wind and turbulence conditions.

Approach trajectory guidance for maximum concealment

An energy-management concept is examined with a view to provision of a near-optimum maneuver guidance system for military aircraft tactical operations. The data thus obtained indicate that the Quiet Short-Haul Research Aircraft, as modeled in the aircraft-specific energy-rate tables, could fly the flight paths in question. The fuel-conservative guidance system's ability to minimize pop-up flight time and carefully coordinate the aircraft's controls for this performance-oriented requirement is demonstrated.

Flight evaluation of augmented controls for approach and landing of powered-lift aircraft

Flight experiments were conducted with Ames Research Center's Quiet Short-Haul Research Aircraft to evaluate the influence of highly augmented control modes on the ability of pilots to execute precision instrument flight operations in the terminal area, particularly approaches to and landings on a short runway. The aircraft is a powered-lift, short-takeoff and landing configuration that is equipped with a modern digital fly-by-wire flight control system, a head-up display, and a solar head-down display that make it possible to investigate control concepts and display format and content for full envelope, powered-lift operations. Considerable attention has been devoted in this flight program to assessing flightpath and airspeed command and stabilization modes developed using nonlinear, inverse model-following methods. The primary benefit of this control concept was realized when the pilot was required to execute a complex transition and approach under instrument conditions and in the presence of a wide range of wind and turbulence conditions.

Fuel conservative guidance for shipboard landing of powered-lift STOL aircraft

A computer-simulation study was undertaken to investigate the application of Fuel Conservative Guidance (FCG) techniques, developed at NASA Ames Research Center, to improve the fuel efficiency and minimize recovery time of powered-lift short-takeoff-and-landing (STOL) airplanes operating from aircraft carriers at sea. The FCG system consists of a set of algorithms whose coefficients and parameters limits match those of the Quiet Short-Haul Research Aircraft. When a flightpath is specified by a set of initial conditions for the aircraft and a set of positional waypoints with associated airspeeds, the FCG synthesizes the necessary guidance commands to capture the specified path at any specified waypoint and to optimize fuel consumption and time fo fly along the path. Closed-form expressions are developed for calculating the altitude profile synthesized by the algorithm. Results of this simulation study show that when restrictions on the approach flightpath imposed for manual operation are removed completely, fuel consumption during the approach was reduced by as much as 38 percent (434 lb of fuel) and the time required to fly the flightpath was reduced by as much as 28 percent (209 sec). Savings because of FCG were produced by: (1) shortening the total flight time and distance, and (2) keeping the airspeed high as long as possible to minimize time spent flying in a powered-lift mode.

Selected results from the quiet short-haul research aircraft flight research program

Selected results from the quiet short-haul research aircraft flight research program

Quiet Short-Haul Research Aircraft Joint Navy/NASA Sea Trials

The Quiet Short-Haul Research Aircraft (QSRA) is a flight facility which Ames Research Center is using to conduct a broad program of terminal area and low-speed, propulsive-life flight research. A joint Navy/NASA flight research program used the QSRA to investigate the application of advanced propulsive-lift technology to the naval aircraft-carrier environment. Flight performance of the QSRA is presented together with the results or the joint Navy/NASA flight program. During the joint program, the QSRA operated aboard the USS Kitty Hawk for 4 days, during which numerous unarrested landings and free deck takeoffs were accomplished. These operations demonstrated that a large aircraft incorporating upper-surface-blowing, propulsive-life technology can be operated in the aircraft-carrier environment without any unusual problems.

Upper Surface Blowing Noise of the NASA Ames Quiet Short-Haul Research Aircraft

An experimental study of the propulsive-lift noise of the NASA-Ames quiet short-haul research aircraft (QSRA) is described. Comparisons are made of measured QSRA flyover noise and model propulsive-lift noise data available in references. Developmental tests of trailing-edge treatments were conducted using sawtooth-shaped and porous USB flap trailing-edge extensions. Small scale parametric tests were conducted to determine noise reduction/design relationships. Full-scale static tests were conducted with the QSRA preparatory to the selection of edge treatment designs for flight testing. QSRA flight and published model propulsive-lift noise data have similar characteristics. Noise reductions of 2 to 3 dB were achieved over a wide range of frequency and directivity angles in static tests of the QSRA. These noise reductions are expected to be achieved or surpassed in flight tests planned by NASA in 1980.

Design and Performance of the Propulsion System for the Quiet Short-Haul Research Aircraft

This paper describes the design and performance of the Quiet Short-Haul Research Aircraft (QSRA) propulsion system. A discussion of the mixed-flow boundary layer control (BLC) system, which uses high and low pressure engine bleed air, is included. This system seriously affected propulsion system performance, particularly engine acceleration characteristics, requiring an integration of BLC system and powerplant controls. Funding limitations for the QSRA Project prevented extensive full-scale testing and systems mockups, resulting in a high reliance on small-scale tests and analytical techniques. Ground tests of the actual aircraft systems showed that the extrapolation of small-scale tests and analytical techniques were in good agreement with measured full-scale results.

Hybrid Upper Surface Blown Flap Propulsive-Lift Concept for the QSRLP

The hybrid upper surface blowing concept consists of wing-mounted turbofan engines with a major portion of the fan exhaust directed over the wing upper surface to provide high levels of propulsive lift, but with a portion of the fan airflow directed over selected portions of the airframe to provide boundary-layer control. NASAsponsored preliminary design studies identified the hybrid upper surface blowing concept as the best propulsive lift concept to be applied to the Quiet Short-Haul Research Aircraft (QSRA) that is planned as a flight facility to conduct flight research at low noise levels, high approach lift coefficients, and steep approaches. Data from NASA in-house and NASA-sponsored small-and large-scale wind-tunnel tests of various configurations using this concept are presented. Nomenclature b = wing span BLC = boundary-layer control CL = lift coefficient, L/qS Cia = 0 = h'ft coefficient at zero angle of attack CL^ ~ 2. ' = lift coefficient at an angle of attack of -2 ° CL^ax = maximum lift coefficient C/ = rolling-moment coefficient, rolling moment/qSb Cn = yawing-moment coefficient, yawing momQnt/qSb CT = thrust coefficient, gross thrust/qS C/z = blowing momentum coefficient, gross thrust from BLC nozzle/qS L -lift Pl£IP^ = pressure ratio, total pressure at engine nacelle exit/tunnel static pressure q = freestream dynamic pressure S = wing area V = velocity W/S = wing loading a = angle of attack 6/r = deflection angle of thejrailing-edge flap