FAA Part 107 Remote Pilot (UAG)Loading and PerformanceEasy
A pilot compares flying a fixed-wing sUAS on a very hot afternoon versus a cool morning at the same field elevation. How will the higher temperature most likely affect performance?
- AAir density remains constant regardless of temperature
- BAir density will decrease, reducing lift and climb performance
- CAir density will increase, improving lift and climb performance
- DHigher temperature increases air density but has no effect on lift
Show answer & explanationAnswer & explanation
Correct answer: B. Air density will decrease, reducing lift and climb performance
Warm air molecules spread farther apart, lowering air density. Less dense air produces less lift and less propeller/motor thrust for a given airspeed, degrading climb and overall performance.
Why the other options are wrong
- A. Temperature is a primary driver of air density changes.
- C. Heat expands air, decreasing density, not increasing it.
- D. Density does decrease with heat, and that directly affects lift.
Temperature and Air Density
Air density decreases as temperature increases, reducing lift, thrust, and overall aircraft performance.
- Hot air = less dense = less lift
- Cold air = denser = better performance
- Density altitude rises with temperature
Memory trick: Hot air is thin air.