Effect of high lift flap systems on the conceptual design of a 1985 short-haul commercial STOL tilt rotor transport

The performances of a derivative concept of a 1985 STOL tilt rotor transport, and of a second concept having a complex mechanical flap system similar to a short field B737 aircraft were compared for a 370 kilometer (200 nautical mile) short haul mission. The flap system of the latter allowed lift to be shifted from the rotor system to the wing, permitting a 26 percent reduction in dynamic component weight, while also permitting the use of a smaller wing. The wing and disc loading of this concept were 5746 (120 psf) and 1915 (40 psf) newtons per square meter, respectively, while the wing and disc loading of the derivative concept were 4788 (100 psf) and 1197 (25 psf) newtons per square meter, respectively. The high lift wing tilt rotor showed slightly improved fuel usage over its entire operating range and about 6 to 8 percent improvement in direct operating costs, resulting from its improved cruise efficiency and reduced weight. Other advantages include improved reliability with potentially reduced maintenance and better riding quality

Unpowered Aerodynamic Characteristics of a 15-Percent Scale Model of a Twin-Engine Commuter Aircraft

An experimental investigation was conducted in the Ames 12-Foot Pressure Wind Tunnel to determine the unpowered aerodynamic characteristics of a 15-percent-scale model of a twin-engine commuter aircraft. Model longitudinal aerodynamic characteristics were examined at discrete flap deflections for various angle-of-attack and wind-tunnel-velocity ranges with the empennage on and off. Data are presented for the basic model configuration consisting of the fuselage, wing, basic wing leading edge, double slotted flaps, midengine nacelles, and empennage. Other configurations tested include a particle-span drooped leading edge (dropped outboard of the engine nacelles), a full-span drooped leading edge, low- and high-mounted engine nacelles, and a single-slotted flap. An evaluation was made of the model mounting system by comparing data obtained with the model mounted conventionally on the wind-tunnel model-support struts and the model inverted

Wind-tunnel investigation of a large-scale model of a lift-cruise fan V/STOL aircraft with extended lift-cruise nacelles

The aerodynamic characteristics of a large-scale model of a lift/cruise fan V/STOL aircraft were determined. The model was equipped with three fans, one mounted in the forward section of the fuselage in a lift mode, and two mounted on top of the wing adjacent to the fuselage in a lift/cruise mode. The data that were obtained include longitudinal and lateral-directional characteristics of the model, with the horizontal tail on and off, for both the powered-lift and cruise configurations. Lateral-directional characteristics were obtained with the horizontal and vertical tail sections removed. Powered-lift data were obtained at several wind-tunnel velocities and at several lift-cruise fan thrust vector angles by varying the position of the hooded deflectors from 0 deg (the cruise condition) to 90 deg

Wind tunnel investigation of a large-scale model of a lift/cruise fan V/STOL aircraft

An investigation was conducted in the Ames 40- by 80-Foot wind tunnel to determine the aerodynamic characteristics of a large scale model of a lift/cruise fan V/STOL aircraft. The model was equipped with three fans, one mounted in the forward section of the fuselage in a lift mode, and two mounted on top of the wing adjacent to the fuselage in a lift/cruise mode. The data that were obtained include longitudinal and lateral-directional characteristics of the model, with the horizontal tail on and off, for both the Powered lift and cruise configurations. Powered lift data were obtained at several wind tunnel velocities and at several lift/cruise fan thrust vector angles by varying the position of the hooded deflectors from 0 deg. (the cruise condition) to 90 deg

Takeoff and landing performance and noise measurements of a deflected slipstream STOL airplane with interconnected propellers and rotating cylinder flaps

A YOV-10A aircraft was modified to incorporate rotating cylinder flaps and interconnected propellers with Lycoming T-53-L11 engines. Flight tests were made to evaluate the low speed handling qualities and performance characteristics. The flight test results indicated that landings could be made with approach speeds of 55 to 65 knots (CL = 4.5) and descent angles of 6 deg to 8 deg for total flap angles of 60 deg to 75 deg. At higher flap angles, deterioration of stability and control characteristics precluded attempts at landing. The noise level on the ground under an 8 deg landing approach path was below 86 PNdB at distances beyond 1 nautical mile from touchdown. Takeoffs were made with 30 deg to 45 deg flaps at lift off speeds of 75 to 80 knots and climb angles of 4 deg to 8 deg. Noise levels were below 83 PNdB at 3.5 nautical miles from the start of ground roll

NACA Research Memorandums

Memorandum presenting the boundary-layer velocity profiles were measured on ten samples of various porous materials and on impervious aluminum plate mounted flush with the inner surface of the side wall of a small wind tunnel. Suction was applied to the back side of the porous test materials through a 4-inch-square opening. Results regarding measurements on the impervious plate and measurements on porous materials without suction and with suction are provided

Attitudes of Older Versus Younger Adults Toward Dentistry and Dentists

A total of 416 adults were interviewed by telephone to gauge their attitudes toward dentistry and dentists. Attitudes of those age 55 and older were compared with those younger than age 55. It was found that 72% of those 55 and older had not visited a dentist In the previous 2 years because they felt it was not necessary; 38.5% of respondents younger than 55 gave this reason. Only 15% of those 55 and older reported that high costs kept them away from the dentis