Private Pilot License (PPL) Aerodynamics Practice Exam

If an airplane weighs 3300 lbs, what is the approximate weight the structure must support during a 30-degree banked turn while maintaining altitude?

1. 3300 lbs

2. 4600 lbs

3. 5100 lbs

4. 6000 lbs

The correct answer is: 4600 lbs

In a banked turn, the aircraft experiences a combination of forces that increase the effective weight that must be supported by the structure. When an airplane banks, the lift vector tilts, and the vertical component of lift must not only counteract the weight of the airplane but also provide the necessary centripetal force to maintain the turn. At a bank angle of 30 degrees, the lift required to maintain altitude calculates as follows: 1. The total lift generated in a turn essentially increases due to the component of lift needing to counteract both the weight of the airplane and provide centripetal force. 2. The formula for lift can be expressed as \(L = W / \cos(\theta)\), where \(L\) is the total lift, \(W\) is the weight of the airplane, and \(\theta\) is the bank angle. 3. When we plug in the numbers for a 30-degree turn, we find: - \(L = 3300 \text{ lbs} / \cos(30^\circ)\) - Since \(\cos(30^\circ)\) is approximately 0.866, we have: - \(L = 3300 \text{ lbs}