Principles of Flight
Aerodynamics, flight mechanics, and aircraft performance fundamentals.
Overview
Principles of Flight covers the science of aerodynamics and how aircraft achieve and maintain flight. This includes understanding the four forces (lift, weight, thrust, drag), airfoil theory, stability and control, performance limitations, and flight envelope boundaries.
Key Topics
1. The Four Forces of Flight
Lift opposes weight, thrust opposes drag. In steady level flight, these forces are in equilibrium. Understanding how changing one force affects the others is fundamental to all flight maneuvers.
2. Airfoil Theory and Lift
How an airfoil generates lift through pressure differential (Bernoulli's principle) and Newton's Third Law. The angle of attack is the primary factor controlling lift, with the critical angle of attack causing a stall.
3. Drag
Parasite drag (form, skin friction, interference) increases with airspeed squared. Induced drag (a byproduct of lift) decreases with airspeed. Total drag is minimized at the speed where these two components are equal.
4. Stalls and Spins
A stall occurs when the critical angle of attack is exceeded, regardless of airspeed or attitude. Factors affecting stall speed include weight, load factor, configuration, and bank angle. Spin recovery follows the PARE procedure.
5. Stability and Control
Longitudinal (pitch), lateral (roll), and directional (yaw) stability. Static stability is the initial tendency to return to equilibrium; dynamic stability determines whether oscillations damp out over time.
6. Load Factor and Maneuvering
Load factor (G-force) increases in turns and pull-ups. In a 60° bank turn, load factor is 2G, which increases stall speed by √2 (×1.41). Understanding the V-n diagram defines the aircraft's maneuvering envelope.
Key Terms & Definitions
Exam Tips
- Tip 1:Remember: stall occurs at a critical angle of attack, NOT at a specific airspeed
- Tip 2:Know the relationship between bank angle and load factor (1/cosθ)
- Tip 3:Understand why induced drag increases at lower speeds and parasite drag at higher speeds
- Tip 4:Learn the effects of flaps on stall speed, lift, and drag
- Tip 5:Know the axis of rotation for each control surface (ailerons, elevator, rudder)
Recommended References
Pilot's Handbook of Aeronautical Knowledge Ch. 5
FAA handbook covering aerodynamics of flight
Principles of Flight (EASA)
European study material for principles of flight examination
Aerodynamics for Naval Aviators
Classic reference text on aerodynamics and aircraft performance
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