Loading and Performance

The smallest area on the exam (7–11%) and the most math-shaped. A handful of concepts covers every question.

Center of gravity

The point where the aircraft's weight balances in every direction - hang it from a string glued there and it hangs level. Set by the manufacturer, normally slightly forward of the center of lift. For a drone, battery and payload placement are what move it.

• CG too far forward = nose-heavy; too far aft = tail-heavy.
• Loading outside the designed CG limits degrades performance: sluggish handling, altered stall behavior, reduced control. That phrase - "performance is negatively affected" - is usually the exam answer.

Load factor

Load factor = the G-forces the aircraft experiences in a maneuver. It is not about takeoff weight or required lift - distractors will offer both.

• Straight-and-level flight = 1.0 G.
• Any turn increases it: banking tilts the lift vector, so the wings/rotors must produce more total lift to hold altitude.
• The chart the exam gives you (testing supplement Figure 2) maps bank angle → load factor: 10° ≈ 1.015 (negligible), 30° ≈ 1.15, 40° ≈ 1.3, 60° = 2.0 - the load factor doubles at 60° of bank. Memorize the 60°=2G point; read the rest off the chart.
• Structural load = aircraft weight × load factor. A 50-lb aircraft in a 40° banked level turn: 50 × 1.3 = 65 lb the structure must support. A 33-lb aircraft at 30°: 33 × 1.15 ≈ 38 lb. The exam wants the closest answer choice, not decimal perfection - and yes, a basic calculator is allowed at the testing center.

Stalls and the critical angle of attack

A stall is an aerodynamic event, not an engine event: airflow separates from the wing and lift collapses.

• Critical angle of attack = the maximum angle between the wing's chord line and the relative wind before that separation happens - typically 17–20°.
• The critical angle of attack is CONSTANT for a given aircraft. It does not change with airspeed, weight, or altitude. Any answer implying it varies is wrong. An aircraft can stall at any airspeed and any attitude - what's fixed is the angle.
• Stall speed rises with weight (a heavier aircraft needs more speed to make enough lift): heavier = stalls faster = worse. It also rises in a banked turn, because load factor raises the effective weight - that's why steep low turns kill.

Density altitude (performance summary)

High density altitude - hot, high, humid - means thin air: less lift, less prop/rotor efficiency, more battery draw, longer takeoff distances for manned aircraft. Full treatment in the weather lesson; here it's the performance punchline: high density altitude = degraded performance.

Traps to drill

• Load factor questions with CG or gross-weight answer choices: wrong axis - the answer involving "maneuvers other than straight-and-level" is the one.
• 60° bank = 2G, exactly.
• Critical AoA never changes; exceeding it always stalls the wing - the same fact gets asked in both directions.
• Heavier = higher stall speed.
• Chart-reading answers are approximate - pick nearest.