Lec 8.4.13 Aerodynamic Forces
Transcript of Lec 8.4.13 Aerodynamic Forces
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AERODYNAMIC FORCES IN FLIGHT
MANEUVERS
Turns
Climbs
Descents
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Still remember the Traffic Pattern?
Upwind Crosswind Downwind (1000ft)
Base - Final
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VFR flying
Where we are and our DESINATION
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Visual Flying Rules- Clear of cloud
- In sight of the ground and sea
- Have other aeroplane in sight
- Avoid collision with other planes or terrain- Not at night
SummaryYOU TAKE CARE OF YOUR SEPARATION
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Clear of Cloud
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VFR Weather Minima
1. General
Visibility 5 km and cloud ceiling of not less
than 1500ft.
In Uncontrolled airspace remain clear of cloud
and in sight of surface under 3000ft.
Not at night!
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Weather Minima
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How can I not
collide with others?
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General Flight Rules
A/C CONVERGING FROM THE RIGHT
TRAFFIC AT THE RIGHT
HAS THE RIGHT OF WAY
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CONVERGING
TRAFFIC AT THE RIGHT
HAS THE RIGHT OF WAY
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General Flight Rules
A/C APPROACH HEAD-ON
EVERYONE TURNS RIGHT!
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General Flight Rules
A/C OVERTAKING
RIGHT OF WAY
OVERTAKE FROM THE RIGHT
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Our AirspaceZones and UCARAs
Controlled and Uncontrolled airspace
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Our Airspace
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Zone Under control (conc. )
Lei Yue MunWaglan Zone
Tuen Mun Zone
Pak MongShum Shek
Place to Note
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Place to Note
UCARA Not Under control
Port Shelter Tolo
New Town
SKARA Border
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Route 1Straight Out departure SSKFANCCC
GRIHBRJoin KaitakCircuit : Downwind runway 13
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Right Crosswind departureHBRGRI
Ma Wan Corridor 1000ft maxTPZ
PAK () - Join CLK Circuit : Final Runway 25L
Route 2
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Sek Kong Airfield
Ex- RAF Sek Kong Camp
HKAC can fly during weekend
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Entry Points
Gaps ()
-: Kadoorie Gap (,)-: Fire Station Gap (,)
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Entry Points
Gaps ()
-: Kam Tin Gap
-: Pagoda
-: Mai Po
(, GFS Only)
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Straight Out departureLYMWAG
PSH TOL
NEW TOWNKDGKadoorie Gap
SKARA
Route 3
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Still have any questions?
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Aerodynamic Forces: Turns
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Aerodynamic Forces: Turns In turns, two forces (lift and weight) would be apparent
In a bank it would be apparent that lift is not act directly oppositeto the weightit now acts in the direction of the bank.
When the airplane banks, lift acts inward toward the center of theturn, as well as upward, meaning the force of lift is divided into twocomponents.
Why? An airplane, like any moving object, requires a sideward forceto make it turn. In a normal turn, this force is supplied by bankingthe airplane so that lift is exerted inward as well as upward.
The force of lift during a turn is separated into two components atright angles to each other.
One component, which acts vertically and opposite to the weight(gravity), is called the vertical component of lift.
The other, which acts horizontally toward the center of the turn, is
called the horizontal component of lift, or centripetal force.
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Aerodynamic Forces: Turns
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Aerodynamic Forces: Turns To provide a vertical component of lift sufficient to hold
altitude in a level turn, an increase in the angle of attack isrequired.
Since the drag of the airfoil is directly proportional to itsangle of attack, induced drag will increase as the lift isincreased. This, in turn, causes a loss of airspeed inproportion to the angle of bank; a small angle of bankresults in a small reduction in airspeed and a large angle of
bank results in a large reduction in airspeed. Additional thrust (power) must be applied to pre-vent a
reduction in airspeed in level turns; the required amount ofadditional thrust is proportional to the angle of bank.
To compensate for added lift, the angle of attack must be
decreased, or the angle of bank increased, if a constantaltitude is to be maintained.
An increase in airspeed results in an increase of the turnradius
Standard Rate Turn
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Aerodynamic Forces: Climbs
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Aerodynamic Forces: Climbs
Aerodynamic Forces: Climbs
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Aerodynamic Forces: Climbs If the climb is entered with no change in power setting,
the airspeed gradually diminishes because the thrust
required to maintain a given airspeed in level flight is
insufficient to maintain the same airspeed in a climb.
When the flightpath is inclined upward, a component
of the airplanes weight acts in the same direction as
the total drag of the airplane, thereby increasing thetotal effective drag.
Consequently, the total drag is greater than the power,
and the airspeed decreases.
The reduction in airspeed gradually results in a
corresponding decrease in drag until the total drag
(including the component of weight acting in the same
direction) equals the thrust.
Aerodynamic Forces: Climbs
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Aerodynamic Forces: Climbs
Aerodynamic Forces: Climbs
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Aerodynamic Forces: Climbs Since in a climb the airplanes weight is not only
acting downward but rearward along with drag,additional power is required to maintain thesame airspeed as in level flight.
The amount of power depends on the angle ofclimb.
When the climb is established so steep that thereis insufficient power available, a slower speedresults.
It will be then the amount of reserve power or
excess power determines the climb performanceof the airplane.
Aerodynamic Forces: Descents
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Aerodynamic Forces: Descents When forward pressure is applied to the elevator control to start
descending, or the airplanes nose is allowed to pitch down, theangle of attack is decreased and, as a result, the lift of the airfoil
is reduced. This reduction in total lift and angle of attack is momentary and
occurs during the time the flightpath changes downward.
The change to a downward flightpath is due to the liftmomentarily becoming less than the weight of the airplane as
the angle of attack is reduced. This imbalance between lift and weight causes the airplane to
follow a descending flightpath.
From the time the descent is started until it is stabilized, theairspeed will gradually increase.
This is due to a component of weight now acting forward alongthe flightpath, similar to the manner it acted rearward in aclimb.
The overall effect is that of increased power or thrust, which inturn causes the increase in airspeed associated with descendingat the same power as used in level flight.
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Four Fundamentals of Flight
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Four Fundamentals of Flight The four fundamentals of flight are
"Straight and Level",
"Level Turns",
"Straight Climbs and Climbing Turns", and
"Straight Descents and Descending Descents"
The four fundamentals of flight are required
to maneuver the aircraft in all phases of
normal and emergency flight.
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Straight and Level
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Straight and Level References: Both flight instruments and Outside visual
Use Pitch, Bank and Power
Primary and Secondary Instruments
If heading deviates, set Bank with Horizon and AI Verify coordination with TC
Bank angle no greater than standard rate: 3 degrees/second
If Altitude deviates:
Set pitch with Horizon and AI Small changes (100') Pitch ONLY
Large changes (>100') Pitch AND Power
Coordination of Controls:
Always keep ball of TC centered
Trim Technique
Trim to relieve control pressure already held. NOT to control yokemovement.
Turns
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Turns Purpose: Change A/C direction
References: Both flight instruments and Outside visual
Banking
Types:
a) Shallow: Stability acts to level wings
b) Medium: A/C tends to hold bank angle
c) Steep: Overbanking tendency
Purpose of bank: Change vertical lift to horizontal lift during which:
(1) Vertical lift opposite gravity
(2) Horizontal lift parallel to earth surface
(3) Resultant vector perpendicular to wings Requires greater AOA to counter loss of lift
Adverse Yaw
1. Caused by lowered aileron on raised wing (more drag)
2. Use of rudder to control
Straight Climbs
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Straight Climbs References: Both flight instruments and Outside visual
Controls used: Elevator, Rudder, and Power
Considerations:
a) As airspeed reduces power must be increased.
b) Climbs require excess thrust (AOA requires excesspower)
Left Turning tendencies:
a) Torque
b) Asymmetrical thrust (P-Factor)
c) Spiral slip stream (slow airspeed) d) Gyroscopic precession (right tendency)
e) Counter Left turning tendencies with rudder
f) Keep Ball Centered on inclinometer
Trim: After established, set trim.
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