Static aerodynamic characteristics of a rocket vehicle with thick wedge fins and sweptback leading and trailing edges

Static aerodynamic characteristics of rocket model vehicles with thick wedge fins with sweptback leading and trailing edges - supersonic wind tunnel testing of vehicle longitudinal stabilit

NASA refan program status

The objective of the refan program is to demonstrate the technical feasibility of substantially reducing the noise levels of existing JT8D powered aircraft. The program consists of the design, manufacturing and testing of the refan engines and modified nacelles and airplanes. Experimental testing was completed for the refan engine both at sea level and at altitude conditions. Ground testing for the B727 side- and center-engine installations and flight testing of the DC-9 with refan engines and acoustic nacelles were performed. Preliminary results presented show that substantial noise reductions were achieved

Aerodynamic Study on Efficiency Improvement of a Wing Embedded Lifting Fan Remaining Open in Cruise Flight

An aerodynamic study on efficiency improvement of a wing embedded lifting fan with a diameter of 0.36 m remaining open and not closed by doors in cruise flight has been conducted. Two of these fans are used to enable an unconventional unmanned transport aircraft of 16 kg maximum take-off mass and almost 2 m wing span to take-off and land vertically. A preliminary study showed that a step for flow deflection on the lower side in front of the lifting fan duct opening increases the lift-to-drag ratio while even a large change of the duct inlet lip curvature radius has only a negligible impact on cruise flight lift-to-drag ratio. For validation and quantification of these effects, an experimental wind tunnel investigation was completed in the German Aerospace Center (DLR) Seitenwindversuchsanlage Göttingen (SWG) using surface pressure, force, and stereo particle image velocimetry measurement techniques. Wind tunnel data showed an increase of the lift-to-drag ratio of 20% of the overall model by the step for all positive angle of attack. Only minor improvement could be achieved due to a larger inlet lip curvature. The wind tunnel measurement data were used for validation of numerical fluid simulation parameters. Using these validated simulation settings, the step height and inclination was optimized for 2°, 4° and 6° angle of attack, the original model size and model sizes scaled by 1:5 and 5:1 to investigate and quantify the influence of a change of the Reynolds number. At a 4° angle of attack of the original size, the lift-to-drag ratio was increased from 4.7 without a step to 6.6 with a step, compared to a lift-to-drag ratio of 20.75 with smoothly closed lifting-fan-ducts