Mass and Balance Flashcards
What does Basic Empty Mass not include?
Pilots and crew
Payload
Ballast
Usable fuel
How does Empty Mass differ from Basic Empty Mass?
BEM includes full oil rather than undrainable oil
BEM + items necessary for flight =
Operating Mass
What fuel does Zero Fuel Mass include?
Unusable fuel
What kind of mass is always greatest? Structural or performance?
Structural
The lower of a maximum structural mass and performance-limited mass is called the…
Regulated mass
Fuel gravity
0.72 Avgas
Oil gravity
0.96 synthetic and 0.90 mineral
1 USG equals how many pounds?
6lb
Turning moment of a force depends on?
Size of the force
Moment arm (length)
Turning moment equation
Force x Distance
How is an Index Unit composed?
Mass.length (Pound.Inch)
Is the Index Unit a mathematical unit?
No, it is a convenient figure
1 Index Unit equals
1000 kg.mm
The lift force of a tailplane depends upon its…?
Airspeed
Forward CG affects stability how?
Stability is greater as tailplane has long moment arm
Aft CG affects stability how?
Stability is less as tailplane has shorter moment arm
Why are fuel tanks often designed to be near the CG?
As fuel is burnt, change in CG is kept to a minimum
Normal category involves what max degree of bank?
60 degrees
Utility category involves what range of bank degrees?
60 to 90 degrees
What manouevre does utility category include that normal category doesn’t?
Spins
What is the datum?
The point from which all items are measured
When is the ‘+’ used for moment arms?
When mass is aft of the datum
When is the ‘-‘ used for moment arms?
When mass is forward of the datum
What elevator force is insufficient if CG is too far forward?
Nose-up force
What elevator force is insufficient if CG is too far aft?
Nose-down force
Longitudinal stability is reduced = very
sensitive to pitch control occurs when?
CG is too far aft
How does CG movement affect glide range?
CG too far aft reduces glide range
How does CG movement affect the flare?`
CG too far forward will mean not enough elevator nose-up force to flare
Why does drag generally increase if CG is too far forward?
A large balancing download is required
from the tailplane, requiring large
elevators deflections increasing DRAG
How is longitudinal stability affected if CG is too far forward?
Longitudinal stability increases
How is stick force affected if CG is too far forward?
Slow to respond to stick inputs hence an
increase in stick force is required
