Question

If an aircraft is climbing at a constant speed in a straight line at a steep angle of climb, the load factor it sustains during the climb is

• A. equal to one
• B. greater than one
• C. positive but less than one
• D. dependent on the weight of the aircraft

Hint:

In steady climb, thrust shares part of the weight’s vertical component, reducing lift demand.

Answer 1

The Correct Option is C

In the context of aerospace engineering, the load factor experienced by an aircraft, often denoted as n, is defined as the ratio of the lift force to the aircraft's weight. Mathematically, it is given by:

n = L/W

Where:

• L is the lift force.
• W is the weight of the aircraft.

During level flight, the load factor is equal to one because the lift force exactly balances the weight of the aircraft. However, when an aircraft is climbing at a steep angle, the dynamics change.

In a climb, the aircraft's velocity vector is inclined relative to the horizontal. As a result, a component of the thrust must counteract gravity, reducing the portion of thrust contributing to lift. Since the lift is oriented perpendicular to the flight path, the effective lift that balances the weight decreases, resulting in a reduced load factor.

Thus, during a climb at a constant speed and straight line, the load factor n can be analyzed as:

• Since thrust contributes to both lift and overcoming gravity, the lift alone doesn’t have to fully balance the weight.
• This results in a load factor that is positive but less than one.

This situation reflects a scenario where the aircraft is dynamically balanced to climb efficiently. Therefore, the correct answer is that the load factor the aircraft sustains during the climb is positive but less than one.