4.3 Load Factor and Maneuvering

What Load Factor Is

Load factor is the ratio of the total aerodynamic load supported by an aircraft to its actual weight, expressed in Gs:

Load Factor (G) = Total Lift / Weight

• In straight-and-level flight, lift equals weight, so load factor is 1G.
• In any banked turn, the aircraft must generate extra lift to hold altitude, so load factor rises above 1G.
• A higher load factor means more force on every structural component and a higher power demand.

The concept originates in manned aviation but appears on the Part 107 test because the same physics applies to multirotor and fixed-wing drones. A 5-pound drone pulling 2G is, structurally, momentarily a 10-pound drone — every arm, mount, and propeller shaft must carry that doubled load even though nothing about the aircraft's mass actually changed.

Two points the exam likes to probe: load factor is expressed in multiples of weight (Gs), not in pounds, so the same bank angle produces the same G on a light or a heavy aircraft; and load factor can be less than 1G during a pushover or a sharp descent, momentarily unloading the structure. The everyday case that matters most, though, is the level coordinated turn, where load factor always exceeds 1G and grows quickly with bank angle.

Load Factor in a Turn

The key fact the exam tests: load factor depends on bank angle, not on aircraft weight. The numbers below are the standard values every applicant should memorize.

Key anchor: A 60-degree bank produces 2G for any aircraft, regardless of weight. The structure and motors must momentarily support twice the aircraft's weight, which is why steep turns are punishing in thin air or near MTOW. The 45-degree / 1.41G and 30-degree / 1.15G values are the next most commonly tested.

Effects on the Aircraft

Structural stress: Aggressive maneuvers load the motor mounts, arms, propeller shafts, and bearings. Exceeding the rated load factor can snap an arm or throw a propeller. Most consumer drones are not rated for high-G aerobatics.

Power demand: Generating more lift means more thrust. A drone holding altitude at 1.5G needs roughly 50% more power than in level flight, accelerating battery drain.

Stall speed (fixed-wing sUAS): Stall speed increases with the square root of the load factor. At 2G the square root of 2 is about 1.41, so stall speed rises about 41%. A fixed-wing drone that stalls at 20 mph in level flight stalls near 28 mph in a 60-degree bank.

Turbulence and Involuntary G

Gusts impose load-factor changes you did not command:

• A strong updraft momentarily increases load factor.
• A strong downdraft decreases it, possibly to near-zero or negative G (the aircraft feels 'unloaded').
• Rapid gust cycles cause load-factor oscillations that fatigue the structure.
• A heavily loaded aircraft in turbulence compounds the stress, because high weight and high G multiply.

Practical Rules for Part 107 Operations

1. Avoid aggressive maneuvers near MTOW — the structure has the least margin when the aircraft is already heavy.
2. Slow down in turbulence — lower airspeed reduces the load factor a given gust can impose.
3. Do not make steep banked turns at low altitude — a mid-turn motor failure needs altitude to recover.
4. Respect the manufacturer's G limits — they are far lower than for crewed aircraft.
5. Treat weight and G as multiplicative — a 6-pound drone at 2G behaves as a 12-pound load on the airframe.

Worked example: You bank a fixed-wing sUAS to 60 degrees to circle a subject. Load factor jumps to 2G, lift demand doubles, stall speed climbs ~41%, and battery current spikes. If a gust then adds another fraction of a G, you can exceed structural limits or stall unexpectedly. The conservative fix is a shallower bank (30-45 degrees) and a wider, slower orbit, which keeps load factor near 1.15-1.41G and preserves margin.

Connecting Load Factor to the Rest of the Chapter

Load factor does not act in isolation. It multiplies against the weight lessons of section 4.1 — a heavy aircraft at high G stresses the structure most — and against the density altitude lessons of section 4.2, because thin air already reduces the surplus thrust a steep turn demands. In high density altitude, a 60-degree bank may simply not be sustainable, and the aircraft will descend or stall as it runs out of thrust. The disciplined remote pilot therefore reduces bank angle when heavy, hot, high, or gusty, treating the published G-by-bank table as a ceiling rather than a target.

For the exam: Memorize 30 = 1.15G, 45 = 1.41G, 60 = 2.0G, and that load factor depends on bank angle alone. Expect a scenario question linking steep turns or turbulence to increased structural stress and reduced margin, and remember that fixed-wing stall speed rises with the square root of the load factor.