M5 Loading and performance

Weight

• Total weight includes the aircraft, batteries, and every payload or attachment
• Must stay under 55 lb (Part 107), and within the manufacturer's limits
• More weight: more power needed, shorter flight time, slower climb

Center of gravity

• Payload off-center shifts CG
• Out-of-limits CG: drone fights to stay level, can lose control
• Secure payloads so they cannot shift in flight (107.49)

Load factor

• Ratio of the total load the aircraft structure supports to its weight, measured in G
• Level flight: 1 G; banked turn: more than 1 G
• 30 deg 1.15 G, 45 deg 1.41 G, 60 deg 2.0 G

Why it matters

• Higher load factor raises stall speed (fixed wing) and demands more thrust (multirotor)
• Stall speed increases with the square root of the load factor
• Aggressive maneuvers with a heavy payload stack these effects

Reading the chart

• Find the bank angle on the horizontal axis
• Go up to the curve, read load factor across to the vertical axis
• Multiply aircraft weight by the load factor

Worked example

• 33 lb drone, 30 deg bank
• Load factor about 1.15
• 33 x 1.154 = about 38 lb of load the structure must support

Check for understanding

1. Load factor in a level 60 deg banked turn?

   Reveal answer

   2 G.

2. What happens to stall speed as load factor increases?

   Reveal answer

   It increases.

3. What does adding an unsecured payload off to one side risk?

   Reveal answer

   A CG shift, reduced control, and possible loss of control; the payload must be secured before flight.