Problem 20: A frequently quoted rule of thumb in aircraft design is that wings should produce about 1000 N of lift per square meter of wing. (The fact that a wing has a top and bottom surface does not double its area.) Part (a) At takeoff, an aircraft travels at 64 m/s, so that the air speed relative to the bottom of the wing is 64 m/s. Given the sea level density of air to be 1.29 kg/m3, how fast must it move over the upper surface to create the ideal lift? Part (b) How fast must air move over the upper surface at a cruising speed of 240 m/s and at an altitude where air density is one-fourth that at sea level?
Fluid Pressure
The term fluid pressure is coined as, the measurement of the force per unit area of a given surface of a closed container. It is a branch of physics that helps to study the properties of fluid under various conditions of force.
Gauge Pressure
Pressure is the physical force acting per unit area on a body; the applied force is perpendicular to the surface of the object per unit area. The air around us at sea level exerts a pressure (atmospheric pressure) of about 14.7 psi but this doesn’t seem to bother anyone as the bodily fluids are constantly pushing outwards with the same force but if one swims down into the ocean a few feet below the surface one can notice the difference, there is increased pressure on the eardrum, this is due to an increase in hydrostatic pressure.
Problem 20: A frequently quoted rule of thumb in aircraft design is that wings should produce about 1000 N of lift per square meter of wing. (The fact that a wing has a top and bottom surface does not double its area.)
Part (a) At takeoff, an aircraft travels at 64 m/s, so that the air speed relative to the bottom of the wing is 64 m/s. Given the sea level density of air to be 1.29 kg/m3, how fast must it move over the upper surface to create the ideal lift?
Part (b) How fast must air move over the upper surface at a cruising speed of 240 m/s and at an altitude where air density is one-fourth that at sea level?
Step by step
Solved in 3 steps with 2 images
