A frequently quoted rule of thumb in aircraft design is that wings should produc

Question

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 56 m/s, so that the air speed relative to the bottom of the wing is 56 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? Numeric   : A numeric value is expected and not an expression. v2 = __________________________________________

Part (b) How fast must air move over the upper surface at a cruising speed of 245 m/s and at an altitude where air density is one-fourth that at sea level? Numeric   : A numeric value is expected and not an expression.

Explanation / Answer

Lift = ½A(U² - V²)

(a) 1000 N = ½ * 1.29kg/m³ * 1m² * (U² - (56m/s)²)
U = 68.45 m/s

(b) 1000 N = ½ * ¼ * 1.29kg/m³ * 1m² * (U² - (56m/s)²)
U = 96.68 m/s

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.