During a climb, the descending blade has a higher angle of attack, so the right side of the propeller disc creates more thrust.

• A. lower
• B. higher
• C. equal
• D. zero

Answer: (B)

In a climb the aircraft’s flight path is tilted upward, so the air flowing through the propeller disk isn’t symmetrical. The blade that’s moving downward (the descending blade) encounters air with a greater effective angle between the blade’s chord line and the resultant relative wind. With the same blade pitch, this higher angle of attack increases the aerodynamic lift—hence thrust—for that blade. Since the right side of the disc corresponds to that descending blade, it produces more thrust on that side. That’s why the correct description is that the descending blade has a higher angle of attack.