Assembly and Rigging – Fixed-Wing & Rotary-Wing Fundamentals

Comprehensive vocabulary flashcards covering fixed-wing aerodynamics, stability, control surfaces, rigging hardware, and rotary-wing flight controls and rotor systems to aid exam preparation.

Aerostatic Lift

Lift generated by a body lighter than the surrounding air (e.g., balloons, airships).

Aerodynamic Lift

Lift produced by the motion of an aircraft through the air as a result of pressure differences around an airfoil.

Bernoulli’s Principle

States that as the velocity of a fluid increases, its pressure decreases; fundamental to understanding wing lift.

Airfoil

Any surface, such as a wing, designed to obtain lift from air moving over it.

Camber

The curvature of an airfoil above or below the chord line; increased camber generally increases lift.

Chord Line

A straight line connecting the leading and trailing edges of an airfoil.

Angle of Attack (AOA)

The acute angle between the wing’s chord line and the relative wind.

Angle of Incidence

Fixed angle between the wing chord line and the aircraft’s longitudinal axis; set by design, not changed in flight.

Aspect Ratio

Ratio of wingspan to average chord; higher aspect ratio generally yields greater lift and less induced drag.

Fineness Ratio

Ratio of airfoil chord to maximum thickness; affects skin friction and turbulence.

Lift-to-Drag Ratio (L/D)

Measure of aerodynamic efficiency; the higher the ratio, the more efficient the wing.

Induced Drag

Drag resulting from lift production; increases with greater angle of attack and lower airspeeds.

Parasite Drag

Drag not associated with lift (form, profile, interference); increases with airspeed.

Form Drag

Parasite drag caused by the shape of an object moving through air.

Profile Drag

Parasite drag produced by skin friction over an airfoil’s surface.

Interference Drag

Additional drag created where airflow meets at junctions (e.g., wing–fuselage intersections).

Total Drag

Sum of induced and parasite drag acting on an aircraft.

Dihedral Angle

Upward angle of wings relative to the horizontal plane; provides lateral (roll) stability.

Sweepback

Rearward angle of wings relative to perpendicular of the fuselage; delays shock waves at high speed and contributes to directional stability.

Center of Pressure (Center of Lift)

Point along the chord where the resultant lift acts; moves with changes in AOA.

Stall

Loss of lift due to airflow separation when AOA exceeds critical value.

Aileron

Primary roll-control surface located on the trailing edge of each wing tip.

Differential Ailerons

Aileron system where the up-going aileron moves further than the down-going one to reduce adverse yaw.

Elevator

Tail surface hinged to the horizontal stabilizer that controls pitch.

Stabilator

Single-piece horizontal tail that combines stabilizer and elevator functions; pivots for pitch control.

Rudder

Vertical tail surface controlling yaw about the vertical axis.

Trim Tab

Small adjustable tab on a primary control surface used to relieve control pressures for hands-off flight.

Balance Tab

Tab that moves opposite the control surface to assist the pilot by aerodynamic force; may double as trim tab.

Servo Tab

Tab controlled directly by the pilot that aerodynamically positions the main control surface.

Anti-Servo Tab

Tab that moves with the control surface to make it harder to deflect and provide stability (common on stabilators).

Spring Tab

Tab linked by springs to assist control only at high aerodynamic loads.

Downspring

Mechanical spring that applies nose-down force on elevator to prevent stalls when CG is aft.

Vortex Generator

Small fin on wing surfaces that energizes boundary layer, delaying airflow separation at high speeds.

Winglet / Tip Dihedral

Upward-turned wing tip or added dihedral to reduce wing-tip vortices and improve efficiency.

Plain Flap

Simple hinged flap on wing’s trailing edge that increases lift and drag when deflected.

Split Flap

Flap that deflects from the lower wing surface creating large drag increase as well as lift.

Slotted Flap

Flap creating a slot for high-energy air to flow over the flap, delaying separation.

Fowler Flap

Flap that slides rearward and down, increasing wing area and camber for significant lift increase.

Triple-Slotted Flap

High-lift system with multiple flap panels forming slots, maximizing lift generation.

Kruger Flap

Leading-edge flap that pivots forward from wing underside to increase camber.

Leading-Edge Slat

Extendable device forming a slot at wing leading edge, allowing higher AOA before stall.

Canard

Forward horizontal surface providing lift and pitch control; stalls before main wing to aid recovery.

Longitudinal Axis

Nose-to-tail axis around which roll occurs.

Lateral Axis

Wing-tip to wing-tip axis around which pitch occurs.

Vertical Axis

Top-to-bottom axis around which yaw occurs.

Static Stability

Initial tendency of an aircraft to return to equilibrium after disturbance.

Dynamic Stability

Time history of the aircraft’s response after a disturbance (damping over time).

Positive Stability

Tendency to return to original condition after disturbance.

Neutral Stability

Tendency to remain in new condition after disturbance.

Negative Stability

Tendency to diverge further from original condition after disturbance.

Longitudinal Stability

Stability about the lateral axis (pitch); influenced by CG position and tail design.

Lateral Stability

Stability about the longitudinal axis (roll); aided by wing dihedral, sweep, and high-wing placement.

Directional Stability

Stability about the vertical axis (yaw); primarily provided by the vertical stabilizer.

Control Cable

Steel cable transmitting control inputs; classified by construction such as 7×19 extra-flexible.

Fairlead

Guide through which a control cable passes to prevent rubbing against structure.

Pulley Guard

Device that prevents a cable from jumping out of a pulley groove.

Turnbuckle

Adjustable fitting used to set and lock control-cable tension.

Safety Wire (Turnbuckle Locking)

Method of securing turnbuckle barrels using clips or wire wraps to prevent loosening.

Tensiometer

Tool used to measure tension in control cables.

Nicopress® Sleeve

Copper sleeve swaged onto cable to form eye or splice with 100 % cable strength.

Push-Pull Rod

Rigid tube with rod ends transmitting control forces where cables are impractical.

Torque Tube

Rotational shaft used to transmit control input through aircraft structure.

Dihedral Board

Special board with spirit level used to measure wing dihedral angle.

Incidence Board

Tool used with level to measure wing angle of incidence relative to fuselage datum.

Control Surface Protractor

Device with suction cup used to measure deflection angles of ailerons, elevators, rudders.

Collective Pitch Control

Helicopter control that changes pitch of all rotor blades simultaneously to vary lift/thrust.

Cyclic Pitch Control

Helicopter stick that tilts rotor disc by varying blade pitch cyclically, providing directional control.

Swashplate Assembly

Rotating and stationary plates that translate pilot control inputs to changing rotor blade pitch.

Stabilizer Bar (Flybar)

Gyroscopic bar providing rotor stability and damping to mitigate gusts and pilot over-control.

Rotor Blade Flapping

Vertical movement of rotor blades about a hinge to compensate for dissymmetry of lift.

Lead-Lag (Drag) Hinge

Rotor hinge allowing blades to move fore-aft to relieve in-plane stresses from flapping changes.

Feathering

Rotation of rotor blade about its spanwise axis to change pitch angle.

Fully Articulated Rotor

Rotor system whose blades can flap, lead-lag, and feather independently.

Semirigid Rotor

Two-blade rotor mounted on teetering hinge; blades flap as a unit and feather individually.

Rigid Rotor

Rotor system with blades fixed to hub (no flapping or lead-lag hinges) but able to feather.

Dissymmetry of Lift

Difference in lift between advancing and retreating rotor blades in forward flight.

Coning Angle

Upward bending of rotor blades during lift as centrifugal force balances blade lift.

Autorotation

Flight condition where rotor turns due to upward airflow rather than engine power.

Sprag-Type Freewheeling Unit

Clutch allowing rotor to spin freely during autorotation when engine power is lost.

Tail Rotor (Anti-Torque Rotor)

Small rotor producing lateral thrust to counter main-rotor torque and control yaw.

Fenestron

Shrouded tail-rotor system offering increased safety and reduced noise.

NOTAR System

No-tail-rotor design using directed airflow and Coanda effect along tail boom to counter torque.

Collective Pitch Sleeve

Component sliding up/down rotor mast to change blade pitch collectively.

Pitch Change Link

Rod transmitting swashplate motion to rotor blade pitch horn.

Blade Tracking

Ensuring rotor blades follow same tip-path plane; checked with flags or strobe lights.

Chadwick-Helmuth Balancer

Electronic analyzer used to measure and correct rotor vibration and balance.

Coanda Effect

Tendency of fluid jet to be attracted to a nearby surface; exploited in NOTAR systems.

Rotorcraft Coning

Upward bending of blades under lift; increases blade angle relative to plane of rotation.

Relative Wind (Rotor)

Airflow opposite to rotor blade’s direction of motion, varies between advancing and retreating sides.

Dissymmetry Correction

Combination of blade flapping and cyclic feathering that equalizes lift in forward flight.

Main Rotor Mast

Vertical shaft transmitting engine power to rotor head.

Pitch Horn

Lever on rotor blade root used to change pitch via control links.

Static Stops

Physical limits preventing excessive flapping of semirigid rotor blades at low RPM.

Rotor Coning Angle Bisector

Line midway between coned blades along which resultant lift acts.

CG (Center of Gravity)

Point where aircraft weight is considered to act; must remain within limits for stability.

Empennage

Tail assembly of an aircraft, including stabilizers, elevators, and rudder.

Rigging Pin

Manufacturer-provided pin to lock controls in neutral for adjustment and cable tensioning.

Fairlead Split/Solid

Guides (split removable or solid) supporting cables; split types allow installation without cable removal.

Cable 7×19

Common extra-flexible aircraft control cable with 7 strands of 19 wires each.

TCDS (Type Certificate Data Sheet)

FAA document listing essential specifications and limits for a certificated aircraft type.