Weight and BalanceWeight and Balance

Joey GiangrassoJoey Giangrasso

This is a study tool developed by Joey Giangrasso as part of the development training for CFI certification under the supervision of Joseph J. Zubay, CFI.

Weight and BalanceWeight and Balance

SafetySafety

Calculating Center of Gravity (CG)Calculating Center of Gravity (CG)

Loading configurationsLoading configurations

SafetySafety Stay within the limitationsStay within the limitations

Center of GravityCenter of Gravity Location in airplane where all forces Location in airplane where all forces

are balancedare balanced

All three axes pass through CGAll three axes pass through CG

String analogy String analogy

CG RangeCG Range Check it out one timeCheck it out one time

Weight at a Distance Weight at a Distance Origin (Place to Start) Origin (Place to Start)

Weights are known Weights are known

See Saw See Saw • Middle Middle • Weight on both ends Weight on both ends

INSERT PICTURE HEREINSERT PICTURE HERE

AirplanesAirplanes

Datum Line=imaginary line of Datum Line=imaginary line of referencereference

Arm=distance from datum (InchesArm=distance from datum (Inches

Weight=measured (pounds)Weight=measured (pounds)

Moment Moment

More TermsMore Terms Gross Take Off WeightGross Take Off Weight max max

weight at take offweight at take off

1 gal1 gal AvGas = AvGas = 6 lbs6 lbs 1 gal 1 gal Oil = Oil = 7.5 lbs7.5 lbs

Basic Empty WeightBasic Empty Weight normally normally includes unusable fuel and full oil includes unusable fuel and full oil (Early 1970s) (Early 1970s)

EquationsEquations

Moment=Weight x ArmMoment=Weight x Arm

Center of Gravity = Center of Gravity = Total MomentTotal Moment Total WeightTotal Weight

The TableThe Table

CG=Total Moment/Total Weight=_______________

Limitations

Forward _________(CG or Mom) Aft ______(CG or Mom)

Two ChartsTwo Charts Used to determine moments Used to determine moments

• READ EVERYTHING ON THE CHART READ EVERYTHING ON THE CHART FIRSTFIRST

• Figure 35Figure 35

Table Table

Line Graph Line Graph

Two ChartsTwo Charts Used to determine moments Used to determine moments

• READ EVERYTHING ON THE CHART READ EVERYTHING ON THE CHART FIRSTFIRST

Table Table

Line Graph Line Graph

SAMPLE 1SAMPLE 1 Basic Empty Weight (B.E.W.) 2015lbsBasic Empty Weight (B.E.W.) 2015lbs Moment Moment

155,400 155,400 Front 200lbsFront 200lbs Back 100lbsBack 100lbs Fuel 24gals Fuel 24gals

AND THE ANSWER IS…..AND THE ANSWER IS….. CG=79.75CG=79.75

Total weight 2479Total weight 2479 Total moment 197,720Total moment 197,720

Two ChartsTwo Charts Used to determine moments Used to determine moments

• READ EVERYTHING ON THE CHART READ EVERYTHING ON THE CHART FIRSTFIRST

Table Table

Line GraphLine Graph

Sample 2Sample 2 B.E.W 1350 lbsB.E.W 1350 lbs Empty Moment 51500 inch-lbsEmpty Moment 51500 inch-lbs Front 200lbsFront 200lbs Back 200lbsBack 200lbs Fuel 30 galsFuel 30 gals Oil 15qtsOil 15qts

And the answer is…..And the answer is….. Total moment 81800Total moment 81800

Total weight 1945Total weight 1945

Within limitations…..YESWithin limitations…..YES

Forward and Aft LoadingForward and Aft Loading Forward Forward

AftAft