Term
Which statement relates to
Bernoulli's principle? |
|
Definition
Air
traveling faster over the curved upper
surface of an airfoil causes lower
pressure on the top surface.
Bernoulli's principle states in part
that the internal pressure of a fluid
(liquid or gas) decreases at points
where the speed of the fluid increases.
|
|
|
Term
Lift produced by an airfoil is the
net force developed perpendicular to the
|
|
Definition
Relative
wind
Lift produced by an airfoil is the
net force developed perpendicular to the
relative wind.
|
|
|
Term
An airplane leaving ground effect
will |
|
Definition
Experience
a decrease in stability and a nose up
change in moments.
An Airplane will: require an increase
in angle of attack to maintain the same
lift coefficient, an increase in induced
drug & thrust required, decrease in
stability & nose up change in moment,
reduction in static source & increase in
indicated airspeed. |
|
|
Term
Which characteristics of a spin is
not a characteristic of a steep spiral? |
|
Definition
Stalled
wing
During a spin, both wings are stalled
although 1 wing in less stalled than the
other. In a steep spiral (steep,
descending turn), the wings are flying
at a relatively low angle of attack and
at a high airspeed. |
|
|
Term
As the angle of bank is increased,
the vertical component of lift |
|
Definition
Decreases
and the sink increases
In a streight-and-level flight the
vertical component of lift acts dirctly
opposite to the component of gravity or
weight. The vertical component of lift
decreases. As a result, gravity is not
offset by as much vertical lift, and the
sink rate increses. |
|
|
Term
When rolling out of a steep-banked
turn, what causes the lowered aileron to
create more drag than when rolling into
the turn? |
|
Definition
The wing's
angle of attack is greater as the
rollout is started.
When rolling out of a turn, the
adverse yaw effect caused by the
loweered aileron is more apparent than
rolling into a turn, due to the higher
angle of attack, wing loading, and the
slower airspeed of the lowered wing wher
rollout is started. |
|
|
Term
If the aircraft's nose initially
tends to move farther from its original
position after the elevator control is
pressed forward and released, the
aircraft displays |
|
Definition
Negative
Static Stability
When the airplane's nose moves
farther from its original position, it
has the undesirable characteristics of
negative static stability. |
|
|
Term
Which type of flap creates the least
change in pitching moment? |
|
Definition
Split
The split flap creates the least
change in pitching moment because,
although it provides lift, it also
results in considerably more drag than
other types of flaps. Accordingly, it
requires more power during approaches. |
|
|
Term
Which statement is true relating to
the factors which produce stalls? |
|
Definition
The
stalling angle of attack is independent
of the speed of airflow over the wings.
While the stalling speed of a
particula airplane varies, the airplane
will always stall at the same angle of
attack regardless of airspeed, weight,
load factor, or density altitude. |
|
|
Term
Which type of flap is characterized
by large increases in lift coefficient
with minimum changes in drag? |
|
Definition
Fowler
When extended, he fowler flap
increases the angle of attack, wing
camber, and wing area,which provides
added lift without significatly
increasing drag. Thus, the fowler flap
produces large increases in lift
coefficient with minimum changes in
drag. |
|
|
Term
During flight with zero angle of
attack, the pressure along the upper
surface of a wing would be |
|
Definition
Less than
atmospheric pressure
Zero angle of attack means that the
chord line of the wing coincides with
the relative wind. Air flows a greater
distance oe the upper wing surfae than
the lower wing surface of an
asymmetrical airfoil, the upper surface
has a lower pressure (less than
atmospheric pressure) than the lower
surface. |
|
|
Term
Why does increasing speed also
increase lift? |
|
Definition
The
increased impact of the relative wind on
an airfoil's lower surface creates a
greater amount of air being deflected
downward.
Increasing speed increases the air
flowing over and under an airflow. The
increased impact of teh relative wind on
an airfoil's surface creates a greater
amount of air being deflected downward,
producing greater lift. |
|
|
Term
During a steady climb, the angle of
climb depends on |
|
Definition
Excess
thrust
For a given weight of the airplane,
the angle of climb depends on the
difference between thrust and drag, or
the excess thrust. The maximum angle of
cloimb wold occur where there exists the
greatest difference between thrust
available and thrust required. |
|
|
Term
If an increase in power tends to make
the nose of an airplane rise, this is
the result of the |
|
Definition
Line of
thrust being below the center of gravity
If an increase in power tends to make
the nose of an airplane rise, it is an
indication that the line of thrust is
below the center of gravity. This
combines with the changing load on the
tail surface to create a pitch-up
attitude. |
|
|
Term
The force which imparts a change in
the velocity of a mass is called |
|
Definition
Thrust
Thrust is the force which imparts a
change in the velocity of the mass. It
may be measured in pounds but has no
element of time or rate. |
|
|
Term
That portion of the aircraft's total
drag created by the producion of lift is
called |
|
Definition
Induced
drag, and is greatly affected by changes
in airspeed
Induced drag is the undesirable but
unavoidable by-product of lift and is
greatly affected by changes in airspeed.
The slower the airplane flies, the
greater the coefficient of lift and thus
the greater the induced drag. |
|
|
Term
The point on an airfoil through which
lift acts is the |
|
Definition
Center of
pressure
Although lift is generated over the
entire wing, an imaginary point is
established which represents the
resultant of all lift forces. This
single point is the center of lift, also
known as the center of pressure. |
|
|
Term
An aircraft wing is designed to
produce lift resulting from |
|
Definition
Positive
air pressure below the wing's surface
and negative air pressure above the
wing's surface.
In the same period of time the air
flowing over the curved top of the wing
must travel farther than the air flowing
along the flat bottom. This means the
air on top must go faster. Bernoulli's
principle. |
|
|
Term
When the angle of attack of a
symmetrical airfoil is increased, the
center of pressure will |
|
Definition
Remain
unaffected
Unlike that of an asymetrical
airfoil, the center of pressure of a
symmetrical airfoil remains unaffected,
regardless of angle of attack. |
|
|
Term
Maximum gliding distance of an
aircraft is obained when |
|
Definition
Induced
drag and parasite drag are equal
The maximum gliding distance of an
aircraft is obtained when the total drag
is the minimum, and L/D ratio is at the
maximum. Minimum drag occurs when
induced drag and parasite drag are
equal. |
|
|
Term
As airspeed increases in level
flight, total drag of and aircraft
becomes greater than the total drag
produced at the maximum lift/drag speed
because of the |
|
Definition
Increase
in parasite drag
As airspeed increases, the total drag
of an aircraft becomes greater than the
total produced at L/DMAX
because of the increase in parasite
drag.
|
|
|
Term
During a steady climb, the rate of
climb depends on |
|
Definition
Excess
power
For a given weight of the airplane,
the rate of climb depends on the
difference between the power available
and the power required, or the excess
power. The maximum rate would occur
where there exists the greatest
difference between power required and
power available. |
|
|
Term
Lift produced by an airfoild is the
net force developed perpendicular to the |
|
Definition
Relative
wind
Lift produced by an airfoil is the
net force developed perpendicular to the
relative wind. |
|
|
Term
Which statement is true regarding the
forces acting on an airplane in a
steady-state climb? |
|
Definition
The sum of
all upward forces is equal to the sum of
all downward forces
In a steady flight condition, the
opposing forces are equal. Thus, in
steady climb, descent, or
straight-and-level flight, total upward
forces equal total downward forces. |
|
|
Term
Changes in the center of pressure of
a wing affect the aircraft's |
|
Definition
Aerodynamic balance and controllability
Center of pressure (CP) is the
imaginary but determinable point at
which all of the upward lift forces on
the wing are concetrated. At high angles
of attack the CP moves forwar while at
low angles of attack the CP moves aft.
The relationship of the CP & CG affects
aerodynamic balance and controllability. |
|
|
Term
An airplane would have a tendeny to
nose up and have an inherent tendency to
enter a stalled condition when the
center of pressure is |
|
Definition
Forward of
the center of gravity
As the angle of attact increases, the
center of pressure moves forward. If it
moves forward of the center of graity,
it will ted to raise the nose of the
airplane, thus increasing the angle of
attack een more. This will lead to a
stalled condition. |
|
|
Term
The resistance, or skin friction, due
to the viscosity of the air as is passes
along the surface of a wing is called |
|
Definition
Profile
drag
Profile drag is the resistance, or
skin friction, due to the viscosity
(stickiness) of the airas it passes alog
the surface of the wing. |
|
|
Term
Which statement describes the
relationship of the forces acting on an
aircraft in a constant-power and
constat-airspeed descent? |
|
Definition
Thrust is
equal to drag; lift is equal to weight
In a steady flight condition, no
change in speed or flight path occus.
The forces that oppose each other are
also equal to each other. Lift equals
weight, and thrust equals drag in a
steady climb, descent, or
straight-and-level flight. |
|
|
Term
Which relationship is correct when
comparing drag and airspeed? |
|
Definition
Induced
drag varies inversely as the square of
the airspeed
Parasite drag increases as the square
of the airspeed, and induced drag varies
inversely as the square of the airspeed. |
|
|
Term
When considering the forces acting
upon an airplane i straight-an-level
flight at constant airspeed, which
statement is correct? |
|
Definition
Weight
always acts verticaly toward the center
of the Earth
Weight is the force which is caused
by gravity accelerating the mass of the
airplane and alaways acts verticaly
toward the center of the Earth. |
|
|
Term
As airspeed decreases in level
flight, total drag of an aircraft
becomes greater than the total drag
produced at the maximum lift/drag speed
because of the |
|
Definition
Increase
in induced drag
As airspeed decreases the total drag
of an aircraft becomes greater than the
total drag produced at L/DMAX
because of the increase in induced drag.
The lower the airspeed the greater the
angle of attack required to produce lift
to equal the sum of the downward forces
& consequently the induced drag will be
greater. |
|
|
Term
If an airplane's gross weight is 3250
pounds, what is the load acting on this
airplane during a level 60°
banked turn? |
|
Definition
6500
pounds
Load factor is the ratio of the total
load supported by the airplane's wing to
the actual weight of the airplane and
its contents. A level 60° bank imposes a
load factor of appreximately 2.0. Thus,
imposing a load factor of 2.0 on an
airplane that weights an actual 3250 lb
would impose a wingload of 6500 lb. |
|
|
Term
An airplane as a normal stalling
speed of 60 MPH but is forced into an
accelerated stall at twice that speed.
What maximum load factor will result
from this maneuver? |
|
Definition
4 G's
A rule for determining the speed at
which an airplane will stall is that the
stalling speed increases in proportion
to the square root of the load factor.
Thus, in order to force an accelerated
stall at twice the normal stalling
speed, the load factor would have to be
4 since square root of 4 is 2. |
|
|
Term
A sweptwing airplane with weak static
directional stability and increased
dihedral causes an increase in |
|
Definition
Dutch roll
tenency
A sweptwing airplane has an increase
in dihedral effect. When an airplane's
dihedral effect is large in comparison
with its static directional stability,
its Dutch roll tendencies will increase. |
|
|
Term
A rectangular wing, as compared to he
other wing platforms, has a tendency to
stall first at the |
|
Definition
Wing root
providing adequate stall warning
A rectangular wing as compared to
other wing platforms, has a tendency to
stall first at the wing root, with the
stall progression toward the wingtip,
which provies adequate stall warning.
Because the wingtips and the ailerons
stall later, you are provided aileron
control in avoiding and recovering from
the stall. |
|
|
Term
At a constant veocity in airflow, a
high aspect ratio wing will have (in
comparison with a low aspect ratio wing) |
|
Definition
Decreased
drag, especially at a high angle of
attack
An increase in aspect ratio with
constant velocity will decrease the
drag, especially at high angles of
attack, improving climb performance and
decreasing stall speed. |
|
|
Term
If severe turbulance is encountered,
the aircraft's airspeed should be
reduced to |
|
Definition
Maneuvering speed
In severe turbulance, the airplane
should be slowed to its maneuvering
speed (VA), i.e. the airspeed
ta which the airplane will stall before
excessive loads can be imposed on the
wings sufficient to cause structural
damage. |
|
|
Term
The angle between the chord line of
the wing and the longitudinal axis of
the aircraft is known as |
|
Definition
The angle
of incidence
The angle of incidence is the acute
angle formed by the chord line of the
wing and the longitudinal axis of the
aircraft. |
|
|
Term
A line drawn from the leading edge to
the trailing edge of an airfoil and
equidistant at all points from the upper
and the lower contours is called the |
|
Definition
Camber
line
a reference line drawn from the
leading edge to the trailing edge whch
is equidistant at all points from the
upper and lower surface of the wing is
the mean camber line. |
|
|
Term
Which is the est technique for
minimizing the wing-load factor when
flying in severe turbulance? |
|
Definition
Set power
and trim to obtain an airspeed at or
below maneuvering speed, maintain wing
level, and accept variations of airspeed
and altitude.
When in severe turbulance you should
be at or below VA so that the
airplane will stall prior to incurring
structural loads of a magnitude
sufficient to cause stractural damage.
You should attempt to keep the wings
level and accept changes in airspeed and
altitude. |
|
|
Term
The use of a slot in the leading edge
of the wing enables an airplane to land
at a slower speed because it |
|
Definition
Delays the
stall to a higher angle of attack
The use of a slot and/or slat in the
leading edge of the wing provides for
the passage of air, which accelerates
the boundary layer on the upper surface.
The stall is delayed to a higher angle
of attack, thus enabling the airpane to
land at a slower speed. |
|
|
Term
A wing with a very high aspect ratio
(in comparison with a low aspect ratio
wing) will have |
|
Definition
A low
stall speed
An increase in aspect ratio with
costant velocity will decrease the drag,
especialy at a high angle of attack,
improving climb prformance and
decreasing stall speeds. |
|
|
Term
Which subsonic planform provides the
best lift coefficient? |
|
Definition
Elliptical
wing
The best subsonic wing planform from
a lift coefficient standpoint is the
elliptical wing. |
|
|
Term
On which planform does the stall
begin at the wing root and progress
outward toward the wingtip? |
|
Definition
Rectangular wing
Rectangular wings have a tendency to
stall first at the wing root,
progressing toward the wingtp. This
tendency gives adequate stall warning,
adequate aileron effectiveness, and
leads to a wing which is usually quite
stable. Rectangular wings are therefore
favored in the design of low-cost,
low-speed airplanes. |
|
|
Term
Aspect ration of a wing is defined as
the ratio of the |
|
Definition
Wingspan
to the mean chord
The aspect ratio is the ratio of the
wingspan to the mean chord. |
|
|
Term
The purpose of aircraft wing dihedral
angle is to |
|
Definition
Increase
lateral stability
Dihedral is the angle at which the
wings are slanted upward from the root
to the tip. When the airplane sideslips
slightly, one wing is forced down. The
greater angle of attack on the lower
wing produces increased lift, with a
tedency to return the airplane to
wings-level flights, i.e. lateral
stability is enhanced |
|
|
Term
The three axes of an aircraft
intersect at the |
|
Definition
|
|
Term
Action of the ailerons moves the
airplane on its
|
|
Definition
Longitudinal axis
An airplane is moved about its
longitudinal axis (rolling motion) by
action of the ailerons. |
|
|
Term
Action of the elevators moves the
airplane on its |
|
Definition
Lateral
axis
An airplane is moved about its
lateral axis (pitching motion) by action
of the elevators. |
|
|
Term
If the pilot applies right rudder to
a stable airplane, the |
|
Definition
Tail
deflects right and the nose moves right
The rudder pedals and the rudder
itself move in the same direction. By
pressing the right rudder pedal in the
cockpit, the pilot is causing the rudder
to move to the right as well. This
causes the airplane to yaw to the right. |
|
|
Term
The angle of attack of a wing
directly controls the |
|
Definition
Distriution of positive and negative
pressure acting on the wing
The angle of attact of a wing
directly controls the distribution of
positive and negative pressure acting on
the wing by altering the speed of the
airflow over the wing surfaces. |
|
|
Term
The angle between the chord line of
an airfoil and the relative wind is
known as the angle of |
|
Definition
Attack
The angle of attack is the acute
angle between the chord line of the wing
and the direction of the relative wind. |
|
|
Term
The critical angle of attack at which
a given aircraft stalls is dependent on
the |
|
Definition
Design of
the wing
The angle of attack at which an
airplane atalls is dependent upon the
wing design. It is a fixed number,
usually an angle of attack between 15°
and 20°. |
|
|
Term
What action is necessary to make an
aircraft turn?
|
|
Definition
Change the
direction if lift
In straight-and-level flight, lift
acts directly opposite to gravity or
weight. As the aircraft is banked, the
lift is divided into horizontal and
vertical components. This horizontal
component of lift pulls the aircraft
around the turn. |
|
|
Term
How can a pilot increase the rate of
turn and decrease the radius at the same
time? |
|
Definition
Steepen
the bank and decrease airspeed
The rate of turn is dependent upon
the horizontal component of lift. As the
horizontal component is increased
(steepen bank) the rate of turn
increases. The radius of a turn is
dependent upon airspeed. As airspeed is
decreased, the turn radius decreases. |
|
|
Term
Adverse yaw during a turn entry is
aused by |
|
Definition
Decreased
induced drag on the lowered wing and
increased induced drag on the raised
wing
When the pilot applies pressure to
the control stick or turns the control
yoke to the left, the right aileron
surface deflects downward and the left
aileron surface deflects upward. The
downward-deflection aileron produces
more lift and more drag which attempts
to pull or veer the airplane's nose in
the direction of the raised wing. |
|
|
Term
As the angle of bank is increased,
the vertical component of lift |
|
Definition
Decreases
and the sink rate increases
In straight-and-level flight, the
vertical component of lift acts directly
opposite to the component of gravity or
weight. Therefore, the vertical
component of lift decreases. As a
result, gravity is not offset by as much
vertical lift, and the sink rate
increases. |
|
|
Term
|
Definition
|
|