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Design data are presented for a class of high-performance single-engine business airplanes. The design objectives include a cruise speed of 300 knots, a cruise altitude of 10,700 m (35,000 ft), a cruise payload of six passengers (including crew and baggage), and a no-reserves cruise range of 1300 n.mi. Two unconventional aerodynamic technologies were evaluated: the individual and combined effects of cruise-matched wing loading and of a natural laminar flow airfoil were analyzed. The tradeoff data presented illustrate the ranges of wing geometries, propulsion requirements, airplane weights, and aerodynamic characteristics which are necessary to meet the design objectives. very large design and performance improvements resulted from use of the aerodynamic technologies evaluated. Is is shown that the potential exists for achieving more than 200-percent greater fuel efficiency than is achieved by current airplanes capable of similar cruise speeds, payloads, and ranges.

This paper describes experimental and analytical studies of the interior noise of twin-engine, propeller-driven, light aircraft. Experimental results indicate that interior noise levels due to propeller noise can be reduced by reduction of engine rpm at constant airspeed (about 3 dB), by synchronization of the twin engines/propellers (up to 12 dB), and by increasing the distances from propeller tip to fuselage. The analytical model described uses modal methods and incorporates the flat-sided geometrical and skin-stringer structural features of light aircraft. Initial results show good agreement with measured noise transmitted into a rectangular box through a flat panel.

The Federal Aviation Administration (FAA) and the National Aeronautics and Space Administration (NASA) have joined forces in a General Aviation Crashworthiness Program. This paper describes the research and development tasks of the program which are the responsibility of NASA. NASA is embarked upon research and development tasks aimed at providing the general aviation industry with a reliable crashworthy airframe design technology. The goals of the NASA program are: reliable analytical techniques for predicting the nonlinear behavior of structures; significant design improvements of airframes; and simulated full-scale crash test data. The analytical tools will include both simplified procedures for estimating energy absorption characteristics and more complex computer programs for analysis of general airframe structures under crash loading conditions.

A review is made of NASA aerodynamic research of interest to the designer of business aircraft. The results of wind-tunnel and flight studies of several current aircraft are summarized. The attainment of STOL performance is discussed and the effectiveness of several lift augmentation concepts is examined. Finally, the potentialities and problems of flight at and beyond the speed of sound are discussed.

As part of NASA's composite structures crash dynamics research, a general aviation aircraft with composite wing, fuselage and empennage (but with metal subfloor structure) was crash tested at the NASA Langley Research Center Impact Dynamics Research Facility. The test was conducted to determine composite aircraft structural behavior for crash loading conditions and to provide a baseline for a similar aircraft test with a modified subfloor. Structural integrity and cabin volume were maintained. Lumbar loads for dummy occupants in energy absorbing seats were substantially lower than those in standard aircraft seats; however, loads in the standard seats were much higher than those recorded under similar conditions for an all-metallic aircraft.

An investigation has been conducted in the Langley 30- by 60-Foot Wind Tunnel to evaluate the performance and stability and control characteristics of a full-scale general aviation airplane equipped with a natural-laminar-flow wing. The study focused on the effects of natural laminar flow and boundary layer transition, and on the effects of several wing leading-edge modifications designed to improve the stall resistance of the configuration. Force and moment data were measured over wide angle-of-attack and sideslip ranges and at Reynolds numbers from 1.4 × 106 to 2.1 × 106 based on the mean aerodynamic chord. Additional measurements were made using hot-film and sublimating-chemical techniques to determine the condition of the wing boundary layer, and wool tufts were used to study the wing stalling characteristics. The investigation showed that large regions of natural laminar flow existed on the wing which would significantly enhance the cruise performance of the configuration.

A flight test investigation has been conducted to determine the performance of wingtip vortex turbines and their effect on aircraft performance. The turbines were designed to recover part of the large energy loss (induced drag) caused by the wingtip vortex. The turbine, driven by the vortex flow, reduces the strength of the vortex, resulting in an associated induced drag reduction. A four-blade turbine was mounted on each wingtip of a single-engine, T-tail, general aviation airplane. Two sets of turbine blades were tested, one with a 15° twist (washin) and one with no twist. The power recovered by the turbine and the installed drag increment were measured. A trade-off between turbine power and induced drag reduction was found to be a function of turbine blade incidence angle. This test has demonstrated that the wingtip vortex turbine is an attractive alternate, as well as an emergency, power source.