Aerodynamics of sUAS Flashcards
7 cards from real FAA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Aerodynamics of sUAS flashcards as text
How does wind shear affect sUAS flight operations?
Answer: A sudden change in wind speed or direction can cause rapid attitude changes and potential loss of control
Abrupt wind shear can instantly change the relative wind acting on all rotors simultaneously, causing attitude excursions that the flight controller may not recover from quickly enough.
How does operating in hot, humid summer conditions affect sUAS endurance compared to cool, dry conditions?
Answer: Hot, humid conditions reduce endurance because lower air density requires higher RPMs for the same lift
High temperature and humidity reduce air density (increase density altitude), requiring motors to spin faster and consume more power per minute, shortening total flight time.
What is the primary aerodynamic concern when operating an sUAS near large buildings or other tall structures?
Answer: Mechanical turbulence and unpredictable wind gusts caused by airflow disruption around the structures
Buildings disrupt smooth laminar airflow and create mechanical turbulence, eddies, and unpredictable gusts on the leeward side that can cause sudden and severe attitude excursions.
How can a strong tailwind affect an sUAS during high-speed forward flight?
Answer: A strong tailwind reduces relative airspeed over the rotors, decreasing control effectiveness and lift efficiency
Rotor lift and control authority depend on relative airspeed — a strong tailwind reduces the relative wind over the rotors, degrading lift efficiency and pitch/roll control response.
What phenomenon commonly occurs when an sUAS performs a rapid deceleration (quick stop) from high-speed forward flight?
Answer: The aircraft pitches nose-high and may experience a momentary altitude loss before stabilizing
During a quick-stop, inertia carries the aircraft forward while the rotor disc tilts rearward to brake — the nose pitches up, the vertical lift component decreases, and altitude drops momentarily.
How do thermal updrafts and convective activity during midday hours affect sUAS flight stability?
Answer: Thermal updrafts create localized vertical air movement and turbulence that can cause unpredictable attitude changes
Surface heating creates localized columns of rising warm air (thermals) surrounded by cooler descending air, generating pockets of turbulence and vertical air movement that can destabilize an sUAS.
How does operating at high altitude affect both battery performance and the power required to maintain hover?
Answer: Cold temperatures at altitude reduce battery capacity while reduced air density simultaneously requires more power, compounding endurance loss
At high altitude, reduced air density forces motors to draw more power to generate sufficient lift, while colder temperatures reduce available battery capacity — both factors severely shorten endurance.