ALBERT

Description: An investigation has been made in the Langley 8-foot transonic tunnels on the aerodynamic characteristics of a 0.15-scale model of the North American Aviation 255-inch fin-stabilized external store over a maximum Mach number range of 0.60 to 1.2 and on the effects of mounting lugs, of fin orientation, of fin aspect ratio, and of fixed-transition. The Reynolds number (based on a body length of 37.50 inches) varied from 9.8 x 10(exp 6) to 13.1 x 10(exp 6). The results indicate that the static margin of the finned store at low lift coefficients was only 9 percent of body length at subsonic Mach numbers and was reduced to zero at a Mach number of 1.0, Increasing the fin aspect ratio from 1.82 to 2.41 increased the subsonic static margin to 18 percent and provided a minimum margin of 9 percent near a Mach number of l.O. Store mounting lugs or fin orientation had only small effects on the aerodynamic characteristics of the basic store.

Description: An investigation was performed in the Langley Unitary Plan wind tunnel to determine the aerodynamic characteristics of a model of a 450 swept-wing fighter airplane, and to determine the loads on attached stores and detached missiles in the presence of the model. Also included was a determination of aileron-spoiler effectiveness, aileron hinge moments, and the effects of wing modifications on model aerodynamic characteristics. Tests were performed at Mach numbers of 1.57, 1.87, 2.16, and 2.53. The Reynolds numbers for the tests, based on the mean aerodynamic chord of the wing, varied from about 0.9 x 10(exp 6) to 5 x 10(exp 6). The results are presented with minimum analysis.

Description: The hazards of lightning strokes to aircraft fuel tanks have been investigated in artificial-lightning-generation facilities specifically constructed to duplicate closely the natural lightning discharges to air craft determined through flight research programs and analysis of lightning-damaged aircraft over a period of many years. Explosion studies were made in an environmental explosion chamber using small fuel tanks under various simulated flight conditions. The results showed that there is a primary hazard whenever there is direct puncture of the fuel-tank wall, whereas the ignition of fuel by hot spots on tank walls due to lightning strikes is unlikely. Punctures of fuel-tank walls by artificial-lightning discharges produced explosions of the fuel in the mixture range from excessively lean to rich mixtures. None of the aluminum alloys, 0.081 inch thick or over, were punctured by the laboratory discharges representative of natural-lightning discharges to aircraft; however, reliance on this wall thickness for complete protection would not be justified, because occasional strokes are known to be of greater magnitude and because statistics reveal variations in the damage pattern. Data gathered by the Lightning and Transients Research Institute on lightning strokes to aircraft show that 90 percent of the strokes recorded have occurred in the temperature range of -10 to +10 C, where many of the jet fuels are flammable but where aviation gasoline is overrich. Also, 10 percent of the strokes recorded have been to the wings, which are the principal fuel-storage areas for modern aircraft. Thus, there is a hazard, particularly for jet fuels. Certain protective measures are indicated by the studies to date, such as the use of lightning diverter rods, thickening of the wing skin in areas near the most probable stroke paths, and the use of fuel-tank liners in critical areas.