Re: airplane structural terms

Date:         13 Feb 99 02:25:48 
From:         Keith Barr <barr@aerosys-eng.com>
Organization: AeroSys Engineering, Inc.
References:   1
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boeing707 wrote:

> Can somebody please define the following terms:
> 1. Mean Aerodynamic chord (relating to wing structure)
> 2. Percent of mean aerodynamic chord (%MAC) (i think this relates to
> wing loading)

>From ASA's "Flight Engineer Test Prep 99":

     The MEAN AERODYNAMIC CHORD (MAC) is the average distance from
     the leading edge to the trailing edge of the wing.  The MAC
     is specified for an aircraft by determining the average chord
     of an imaginary wing which has the same aerodynamic
     characteristics as the actual wing.

     LEMAC stands for LEADING EDGE of MEAN AERODYNAMIC CHORD.  Its
     position is expressed in inches aft of the datum.

CG of Gravity (CG) of swept wing aircraft is normally calculated as a
percent of MAC.  For example, if MAC is 141.5" and the CG is at 22.5%, the
CG is at 31.84" aft of LEMAC.

> 3. Wing incidence

This is the angle the wing is mounted at on the fuselage.

> 1. STA (relating to fuselage) and how are the STA numbers determined?

STA is the station number, normally in inches aft of the datum used for
weight and balance determination.

--
Keith Barr           AeroSys Engineering, Inc. & New England Airlines
mailto:barr@aerosys-eng.com         Broomfield, CO & Block Island, RI
http://www.aerosys-eng.com/barr                    BN-2, PA-32, PA-28