AC STRUCTURES 1 DEFINITIONS

- removable panel for inspection or maintenance.

Access panel

- maximum stress level allowed in a structure.

Allowable stress

- The downward angle of aircraft wings from the horizontal cross section of the wings.

Anhedral

- a structural member loaded at an angle to its length.

Beam

- underside of central portion of fuselage.

Belly

- spar assembled from front and rear webs separated by upper and lower booms.

Box spar

- out of plane bending, followed by crushing of material under compressive loads.

Buckling

- The beating of an aerodynamic structure or surface by unsteady flow and gusts.

Buffeting

- an aircraft control maneuver where the pilot combines a 180° turn with a climb.

Chandelle

- small angles or simple sheet metal parts for connection of various parts.

Cleat

- single structural member having more than two supports.

Continuous beam

- Air deflected perpendicular to the motion of the airfoil.

Downwash

- maximum stress withstood by material without causing permanent set or deformation.

Elastic limit

- deliberate weak link to prevent overload damage to costly structure.

Fail link

- the principle of designing a structure so that the failure of one part does not affect the safety of the whole.

Fail safe

- secondary structure whose function is to reduce drag.

Fairing

- a temporary structure used to support a permanent structure during its construction and until it becomes self supporting.

Falsework

- aerodynamic fairing giving radius at junction of two surfaces.

Fillet

- an oscillation caused by interaction between structural and aerodynamic effects.

OSCILLATION = SWAYING OR SWINGING

Flutter

- A small plate attached to two or more members of a structure.

Gusset

- structural beam with vertical web and flat upper and lower booms.

I-beam

- A small offset near the edge of a piece of sheet metal.

It allows one sheet of metal to overlap another sheet while maintaining a flush surface.

Joggle

- maintains fuselage shear and bending continuity over the wing center section cut-out.

Keel structure

- an aerial maneuver in which a plane by gradual climbing, banking, and turning traces an imaginary figure eight on its side.

Lazy eight

- single piece of aircraft skin.

Panel

- the principle of putting the least load or force on each component, so that it will last well beyond an expected life.

Safe Life

- a biplane that has a lower wing considerably smaller than the upper.

Sesquiplane

- a non-structural protective panel that is used to block something from view.

Shroud

- particularly strong frame or bulkhead to which a spar is attached.

Spar frame

- normally a strip or beam attached to sheet to resist load normal to surface.

Stiffener

- ratio of steady applied force to resulting displacement or ratio of applied torque to resulting angular deflection.

Stiffness

- has been used to describe lower rear half of main fuselage structure.

Tub

- angle or other sections riveted or bonded at intervals along spar web or fuselage keel to resist buckling in vertical plane.

Vertical stiffener

- a stall during a vertical climb in which the nose of the airplane whips violently forward and then downward.

Whip stall