Chapter 2 Aerodynamics Flashcards
The four forces acting on an airplane are
Lift, weight, thrust, drag
When are the four forces that act on an airplane in equilibrium?
During unaccelerated flight
Airplanes climb because of
Excess thrust
Lift acts at a ___ degree angle to the relative wind
90
The minimum forward speed of the airplane is called the ____ speed
Stall
You can determine the proper climb attitude for your airplane by referring to the
Airspeed indicator
The chord line is an imaginary line connecting the
Leading edge of the wing with the trailing edge
The chord line is used to represent
The general shape of the wing
The definition of chord enables us to understand
The angle the wind meets a wing that may vary in size and shape
Relative wind results from the motion of the
Airplane through the air
Relative wind is ___ and ___ to the airplanes motion.
Opposite to, equal
Relative wind is ___ which way the airplane’s nose is pointed.
Independent of
The term “angle of attack” is defined as the angle
Between the wing chord line and the relative wind
An important principle to understand when dealing with angle of attack is that the nose (therefore the wing) can be pointed on an incline that’s ___ the actual climb path.
Different from
Wings are expressly built to plow through air molecules separating them either above or below while offering little resistance in the ___ direction
Horizontal
Wind deflected downward by the airfoil creates a/an ___ movement of the wing.
Upward
Bernoulli figured out that the faster the air flows over a surface, the ___ pressure it exerts on that surface
Less
Air flowing faster over a curved surface causes a slight ___ in pressure on that surface
Decrease
High velocity airflow over the wing causes a slight decrease in pressure on the wing’s upper surface. In other words, the pressure on ___ the wing is now ___ than the pressure on bottom of the wing.
Top, less
Since high pressure always moves toward low pressure, the wing ( which just happens to be in the way) is pushed ___ in the process.
Upward
Because of the wing’s shape, even at a very small angle of attack, a cambered wing will adds a slight curve and ___ to the wind.
Acceleration
At a relatively slow speed ( such as during takeoff), the wing’s engineered curve isn’t capable of curving or deflecting enough air ___ the produce the necessary lift for flight.
Downward
Raising the nose slightly increases the angle of attack which forces the air to undergo an additional ___ greater than that which the ___ of the airfoil can produce.
Curve, engineered shape
An increased angle of attack permits the airplane to produce the necessary lift for flight at a ___ airspeed.
Slower
As the angle of attack increases, an airplane can fly at a ___ speed and still develop the necessary lift for flight.
Slower
As the angle of attack exceeds approximately 18 degrees the air molecules flowing over the wing don’t negotiate the turn very well. When this happens, they spin off or burble into the free air, no longer providing a uniform, high-velocity, laminar airflow over the wing. The wing ___
Stalls
When the critical angle of attack is exceeded, the airplane will
Stall
All wings have what?
a critical angle of attack
If the wing stalls, you need to do one very important thing:
Reduce the angle of attack to less than its critical value
You can unstall a wing by ___ the angle of attack
Reducing
You should realize that an airplane can be ___ at any attitude or any airspeed
Stalled
Whether an airplane exceeds its critical angle of attack is independent of…
attitude or airspeed
If an airplane stalls, the first step in recovering is to decrease the angle of attack by moving the elevator control ___ or releasing ___ on the elevator control
forward, back pressure
Once the airplane is no longer stalled it should be put back in the desired attitude while making sure you don’t ___ again
Stall
Which of the following may indicate the onset of a stall?
Stall horn sounding, diminished control response, noticeable buffet
When the weight of an airplane is increased, the airplane stalls at ___ indicated speed.
a higher
An increase in weight (apparent or real) means the wings must develop more ___ to remain airborne
lift
The critical angle of attack at which the wing stalls ___
Never changes, regardless of airplane weight
The angle of attack at which an airplane wing stalls will ___
remain the same regardless of gross weight
Increasing the airplane’s weight will not affect the ___ of attack at which the airplane stalls
Angle
Which basic flight maneuver increases the load factor on an airplane as compared to straight-and-level flight?
A turn
If the airplane “feels” twice as heavy as it actually is, then the lift must ___ if the airplane is to maintain altitude.
double
An increased load factor will cause the airplane to
Stall at a higher airspeed
When the bank increases, the nose wants to ___
Pitch down, which results in the pilot pulling on the elevator to maintain altitude, causing an increased angle of attack
Why is it important for a pilot to be especially sensitive to the amount of G-force he or she is experiencing while maneuvering the airplane?
Increasing G-force always means an increase in stall speed
What are the most important parts of your anatomy for avoiding stalls?
Your brain, for planning to avoid steep turns near the ground and your butt for sensing G-force which helps alert you to an increase in stall speed
Drag is the airplane’s natural response to an object’s movement through the ___
Air
Wings are designed to deflect air ___ while offering very little ___ resistance
Vertically, Horizontal
The two basic forms of drag are:
Parasite and induced drag
Parasite drag is the result of
Friction
As airspeed doubles, parasite drag ___
Quadruples
