Aircraft Structures and Components

Vocabulary practice flashcards covering primary and secondary aircraft structures, control surfaces, fairings, and aerodynamic concepts.

Structure

A physical framework arranged to support loads and maintain shape; in aircraft engineering, it maintains shape while transferring flight and ground loads.

Primary Structures

The critical load-bearing components of an aircraft essential for flight safety, whose structural failure would result in catastrophic loss of the aircraft.

Secondary Structures

Non-critical aircraft components that do not bear primary flight or ground loads, but function to enhance aerodynamics, access, or performance.

ATA-100 Specification

A standardized zoning system defined by the Air Transport Association of America using unique three-digit numbers to identify aircraft sections for maintenance.

Cantilever Wing

A wing structure requiring no external bracing, relying entirely on internal spars and ribs to carry flight loads.

Spars

Main longitudinal structural members in an aircraft wing that carry bending loads.

Ribs

Cross-sectional structural members in a wing that maintain its airfoil profile and distribute aerodynamic forces to the skin.

Stringers

Longitudinal stiffening elements attached to the aircraft skin to resist bending and prevent structural buckling.

Monocoque

A fuselage design where the external skin carries nearly all structural loads with minimal internal framing.

Semi-Monocoque

An aircraft fuselage design combining a load-bearing skin with internal frames, bulkheads, and stringers to distribute loads.

Bulkheads

Major vertical cross-sectional frames inside the fuselage that define its contour, transfer concentrated loads, and seal pressurized cabin ends.

Empennage

The tail assembly of an aircraft that provides pitch and yaw stability and control.

Horizontal Stabilizer

A fixed horizontal airfoil in the empennage that provides longitudinal pitch stability and supports the elevators.

Vertical Stabilizer

A fixed vertical fin in the empennage that provides directional yaw stability and supports the rudder.

Oleo Strut

A hydraulic shock absorber strut in landing gear assemblies that uses compressed gas and oil to dissipate touchdown impact energy.

Nacelle

A streamlined external housing surrounding an engine to protect components and reduce aerodynamic drag.

Pylon

A rigid structural mount attaching an engine nacelle to the wing or fuselage while transmitting thrust loads.

Tractor Configuration

A propulsion arrangement where the propeller is mounted at the front of the aircraft, pulling it through the air.

Pusher Configuration

A propulsion layout where the propeller is mounted behind the engine, pushing the aircraft forward.

Fairings

Secondary structural covers designed to smooth airflow across component intersections, reducing parasitic and form drag.

Wheel Pants

Streamlined fairings mounted over non-retractable landing gear wheels to diminish aerodynamic form drag.

Vortex Generators

Small vanes on airfoils that generate micro-vortices to energize the boundary layer and delay airflow separation.

Wing Fences

Vertical chordwise fins on swept wings that impede spanwise airflow and prevent outboard tip stalling.

Leading-Edge Extensions (LEX)

Forward extensions at the wing root that produce high-energy vortices to preserve lift at extreme angles of attack.

Winglets

Near-vertical wingtip appendages that mitigate wingtip vortex formation, thereby lowering induced drag.

Trim Tab

A small adjustable tab on a control surface edge that moves oppositely to aerodynamic forces to maintain hands-off flight balance.

Servo Tab

A tab directly driven by pilot input that deflects opposite to the main control surface to provide aerodynamic assistance.

Anti-Servo Tab

A tab deflecting in the same direction as the main control surface to increase control force resistance and prevent pilot over-controlling.

Spring Tab

A control tab integrated with a spring system that provides aerodynamic control assistance specifically during high-speed maneuvers.

Frise Aileron

An aileron featuring an offset hinge line whose nose extends below the wing when raised to create counteracting form drag.

Inset Hinge

A control surface hinge placed aft of the leading edge to utilize aerodynamic leverage and lower hinge moments.

Aerodynamic Balance

A design extension of a control surface forward of the hinge line that uses dynamic air pressure to assist surface deflection.

Control Horn

A lever arm extending near a control surface hinge line that attaches to cables or rods to provide mechanical advantage.

Adverse Yaw

An unwanted yawing moment opposite to the direction of roll turn created by differential drag on deflected ailerons.

Induced Drag Coefficient Equation

The formula calculating drag due to lift defined as $Cd_i = \frac{Cl^2}{\pi \cdot AR \cdot e}$, where aspect ratio is $AR = \frac{s^2}{A}$.