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Most importantly, the maximum lift-to-drag ratio is independent of the weight of the aircraft, the area of the wing, or the wing loading. It can be shown that two main drivers of maximum lift-to-drag ratio for a fixed wing aircraft are wingspan and total wetted area. One method for estimating the zero-lift drag coefficient of an aircraft is the ...
An example of an optimization proof of concept was done in 2003 by Leoviriyakit using the Boeing 747-200. [4] Using the variable list above, he optimized for only a single point – a lift coefficient of 0.42 and a speed of Mach 0.87, just above cruising.
For conventional fixed-wing aircraft with moderate aspect ratio and sweep, Oswald efficiency number with wing flaps retracted is typically between 0.7 and 0.85. At supersonic speeds, Oswald efficiency number decreases substantially. For example, at Mach 1.2 Oswald efficiency number is likely to be between 0.3 and 0.5. [1]
Like winglets, they increase the effective wing aspect ratio and diminish wingtip vortices, decreasing lift-induced drag. In testing by Boeing and NASA, they reduce drag by as much as 5.5%, compared to 3.5% to 4.5% for conventional winglets. [1] While an increase in span would be more effective than a same-length winglet, its bending moment is ...
Wing loading is a useful measure of the stalling speed of an aircraft. Wings generate lift owing to the motion of air around the wing. Larger wings move more air, so an aircraft with a large wing area relative to its mass (i.e., low wing loading) will have a lower stalling speed.
The lift-to-drag ratio, or L/D ratio, is the amount of lift generated by a wing or vehicle, divided by the drag it creates by moving through the air. A higher or more favourable L/D ratio is typically one of the major goals in aircraft design; since a particular aircraft's needed lift is set by its weight, delivering that lift with lower drag ...
In the definition of load factor, the lift is not simply that one generated by the aircraft's wing, instead it is the vector sum of the lift generated by the wing, the fuselage and the tailplane, [2]: 395 or in other words it is the component perpendicular to the airflow of the sum of all aerodynamic forces acting on the aircraft.
High-lift devices compensate for this design trade-off by adding lift at takeoff and landing, reducing the speed and distance required to safely land the aircraft, and allowing the use of a more efficient wing in flight. The high-lift devices on the Boeing 747-400, for example, increase the wing area by 21% and increase the lift generated by 90 ...