Unit 1 Flashcards
Landing gear
supports airplane during landing & on ground
Fuselage
common attachment point for major structural units of airplane
Wings
airfoils attached to fuselage → main lifting surface
Engine
generates force that provides power to rotate propeller
displace air in opposite direction
Powerplant
engine & propeller (provides thrust to move)
Composite construction
materials never dissolve or merge together (more resistant)
3 primary axes of rotation
pitch, roll, yaw
Pitch is controlled by what?
Pitch = lateral
controlled by elevator
Roll is controlled by what?
Roll = longitudinal
Controlled by ailerons
Yaw is controlled by what?
Yaw = vertical
Controlled by rutter
Attitude
rotation about 3 primary axes
Primary flight controls
ailerons, elevator, rudder
Does flight control effectiveness increase or decrease with speed?
INCREASE b/c more air flow over surface of control device
Aileron
control roll
Empennage
tail section
consists of: stabilizers, rudder, elevator
Elevator
Changes pitch attitude about lateral axis
(located on fixed horizontal stabilizer)
Horizontal stabilizer
provides longitudinal (pitch) stability
Vertical stabilizer
provides directional stability
Stabilator
1 piece horizontal stabilizer & elevator
changes AOA
Canard
small horizontal wing located at the front of some planes (creates lift)
Rudder
used to control yaw
attached to vertical stabilizer (controlled by rudder pedals)
Secondary flight controls
flaps, spoilers, trim systems, leading edge devices
Wing flaps
increase lift & drag
What are the benefits of wing flaps?
- Slower landing speed
- Shorter takeoff/landing
- Steeper angle descent
What are the benefits of spoilers and flaps?
increase rate of descent without increasing speed
Spoilers
high drag devices that disrupt smooth airflow over the wings
Trim systems
small airfoils attached to trailing edge of primary control surfaces
Trim tabs
neutralize control pressure
Antiverso tab
makes yoke less sensitive
(tab deflected into slipstream)
Basic forces
Lift, weight, thurst, drag
act on the airplane during all maneuvers
Bernoulli’s Principle
high speed = low pressure
(wing camber design, lower pressure top above wing → generates lift)
Newton’s 3rd Law of Motion
for every action there is an equal and opposite reaction
Lift
(upward force)
produced by airfoil → acts perpendicular flight path
Weight
force caused by gravity
accelerates mass of airplane toward the Earth
Thrust
propeller acting as an airfoil
(|| longitudinal axis)
Drag
disruption of airflow by wing, fuselage
Induced drag
undesirable but inevitable by-product of lift
Pressure on lower surface wing > upper surface
Parasite drag
resistance of the air as airplane passes through it
Relationship between basic fores in steady, unaccelerated flight?
lift = weight
thrust = drag
airfoils
any surface designed to obtain desired reaction force when in motion
camber
curvature of airfoil from leading edge to trailing edge
Angle of attack (AOA)
angle between wing chord line & relative wind
Angle of attack (AOA)
angle between wing chord line & relative wind
Critical angle of attack
AOA that wing stalls (constant no matter weight, airspeed)
Angle of incidence
angle wing is attached to fuselage
Attitude
relationship of airplane to horizon (ie. pitch and bank angle)
Center of gravity (CG)
point where airplane would balance
Center of lift/pressure
point along chord line where are aerodynamic forces are concentrated
Dihedral angle
angle wings slanted upward
Relative wind
for airplane in flight flows || opposite direction of flight
(flight path determined direction not horizon)
Stall
loss of lift & increase drag
occurs when AOA > critical AOA
Sweepback
angle wings slanted rearward
Washout
wing design
angle incidence wingtip > root
Wing platform
shape/form wing (viewed from above)
Wingspan
max distance from wingtip to wingtip
As airspeed decreases, AOA ? causing induced drag ? parasite drag ?
Decrease airspeed = increase AOA
Causing increase induced drag, decrease parasite drag
What does changing power do?
varies relationship of thrust to drag
(allowing airplane change airspeed altitude)
What does changing AOA do?
varies lift & drag
Why doesn’t altitude affect stall speed?
airspeed indicator directectly related to air density
Relationship between flaps & stall speed?
flaps increase lift, thus decrease stall speed
Relationship between load factor & stall speed?
Stall speed proportional square root of load factor
Other factors that influence stall speed
weight, snow, turbulence, spins
How to recover from a stall?
- move elevator control forward
- apply max power (increase airspeed)
(goal = decrease AOA)
Spin
aggravated stall results in autorotation (corkscrew down path)
Spin recovery
PARE
- Power to idle
- Aileron to neutral
- Rudder opposite of rotation
- Elevator input forward of neutral
Ground effect
interference of ground surface with airflow around plane
Relationship between ground effect & AOA?
How should ground effect be taken into account during takeoffs/landings?
required smaller AOA to produce same lift coeff.
Aircraft may become airborne with insufficient speed → it will fall back down to runway
What makes an airplane turn?
Horizontal component of lift makes planes turn
(counteracts centrifugal force)
Inertia
moving objects continue straight in same direction
Adverse Yaw
lowered aileron produced more lift than raised aileron
How to counteract adverse yaw?
apply RUDDER pressure
What do stable planes do?
return to original position after being disturbed
(easier to fly)
static stability
initial tendency of airplane after equilibrium is distrubed
dynamic stability
overall tendency of airplane after equilibrium is distrubed
What is the most desirable combination of stability?
positive static stability & positive dynamic stability
What determines longitudinal stability?
location CG with respect to CL
(closer CG is to CL = less stable)
Lateral stability
stabilize rolling effect when one wing gets lower than other
Controllability
aircraft’s ability to respond to pilot input
Maneuverability
ability to be operated easily & withstand stress
Torque effect
left turning tendency
How to correct torque effect?
right rudder pressure
When is torque effect the greatest?
low airspeed
high AOA
high power
(ie. takeoff)
What causes torque effect?
Torque reaction, corkscrew, gyroscopic action, p-factor
Load factor
Additional weight carried by wings due to plane’s weight + centrifugal force
Load factor equation
Load factor = total load / total weight
How does load factor effect stall speed, AOA, and bank angle?
Higher load factor =
higher stall speed, higher AOA, higher bank angle
How does load factor effect stall speed, AOA, and bank angle?
Higher load factor =
higher stall speed, higher AOA, higher bank angle
Relationship btw stall speed and load factor?
Stall speed increases proportionally to square root of load factor
Design maneuvering speed (VA)
max speed at which max load can be imposed without structural damage
(Approx 1.7x stall speed)
V-G diagram
graphic representation of operating limitations
VNE
never exceed speed
(structural damage)
Does the AOA at which an airplane wing stalls depend on gross weight?
no! AOA stall remains the same regardless of gross weight
The amount of excess load that can be imposed on the wing of an airplane depends upon the ___
speed of the airplane
An airplane has been loaded in such a manner that the CG is located aft of the aft CG limit. One undesirable flight characteristic a pilot might experience with this airplane would be
difficulty in recovering from stalled condition
An airplane loaded with the Center of Gravity (CG) rear of the aft CG limit could
increase the likelihood of inadvertent overstress.
An aircraft leaving ground effect during takeoff will
experience an increase in induced drag and a decrease in performance.
The left turning tendency of an airplane caused by P-factor is the result of the
propeller blade descending on the right, producing more thrust than the ascending blade on the left.
What causes an airplane (except a T-tail) to pitch nosedown when power is reduced and controls are not adjusted?
The downwash on the elevators from the propeller slipstream is reduced and elevator effectiveness is reduced.
