Definition
Disk loading is the ratio of an aircraft's weight to the area of the rotor disk that supports it, expressed in pounds per square foot. It is calculated by dividing gross weight by the area swept by the rotor blades.
Plain English
It is how much weight each square foot of the spinning rotor has to hold up. A smaller rotor lifting the same weight has higher disk loading; a bigger rotor lifting the same weight has lower disk loading.
Context Anchor
Seen in helicopter performance discussions, especially when comparing hover, climb, and power required.
Derivation
Disk' refers to the flat circular area swept by the rotor blades as they spin — the blades trace out a disk shape in the air. 'Loading' means the weight being carried per unit of area. Together: how much weight is placed on each square foot of that imaginary disk.
Why Pilots Care
Higher disk loading increases power required to hover and reduces climb performance, especially in high density altitude conditions.
Grounding Statement
For the same weight, a larger rotor disk spreads the lifting work over more area; a smaller rotor disk concentrates the work into less area.
Intuition Check
Disk loading is not about a physical disk being loaded with cargo. It is about how much weight is being supported by the circular area swept by the rotor or propeller.
Example Sentence 1
The new utility helicopter has a higher disk loading than the older model, so it requires more power to hover at the same weight.
Example Sentence 2
A helicopter with lower disk loading climbs more readily in hot weather.