Aerodynamics Flashcards
What is Wing Aspect Ratio?
Describe the difference between high aspect ratio and low aspect ratio.
Give me an example of those types of planes
A Square has an aspect ratio of 1:1 or 1/1.
Wing Aspect Ratio is the ratio between it’s Wingspan to the Chord
High aspect ratio:
1. Longer and thinner than low aspect ratio wings
2. Less drag
3. Higher lift to drag ratio
4. More stable
5. Example: glider.
Low aspect ratio:
1. Shorter and thicker wings than high aspect ratio
2. More drag
3. More maneuverable
4. Example: Cessna 172.
What is a Dihedral wing?
Dihedral is the upward angle of an aircraft’s wings, which increases lateral stability in a bank by causing the lower wing to fly at a higher angle of attack than the higher wing.
What is balanced field length?
A balanced field is when the accelerate go and accelerate stop distances are
equal
What is coffin corner?
Coffin corner, a critical flight regime that occurs at high altitudes and high speeds. It refers to the narrow range of altitude and airspeed in which an aircraft’s stall speed and critical Mach number are very close to each other.
At high altitudes, the air density decreases, which affects both the aircraft’s stall speed (minimum lift speed) and its critical Mach number (percentage of the speed of sound).
If an aircraft operates too close to its stall speed, it risks stalling due to reduced lift caused by the thin air at high altitudes. If it flies too fast and reaches or exceeds its critical Mach number, it may experience a loss of control and encounter adverse aerodynamic effects, such as shockwave-induced buffet or control surface effectiveness reduction.
What is green dot? And when would it be useful in cruise?
The speed that optimizes the Iift/drag ratio. Would be the best glide speed in a
dual engine failure scenario
What is mack tuck?
Approaching Mach 1.0 the center of lift moves so far aft that the elevator no longer has the authority to overcome a downward pitching tendency
Can you describe some indications you might be entering a microburst?
Increasing airspeed, throttle rolling back, nose pitching down to maintain altitude
Tell me about a supercritical wing?
A supercritical airfoil is an airfoil designed primarily to delay the onset of wave
drag in the transonic speed range
What is the maximum bank angle under normal law with maximum side stick deflection?
67 degrees
What are accelerated stop distances?
The total distance required to accelerate a twin engine airplane to a specific speed where if an engine failure happens, the airplane can stop on the remaining runway
What is a Dutch Roll
Dutch roll is a type of aircraft motion, consisting of an out-of-phase combination of “tail-wagging” and rocking from side to side
How does a spin occur?
In one wing the lift is increased, and on the other one the lift is decreased with an increase of drag
What is VRef?
1.3 stall speed for a configuration
What is V1,V2, Vref, Vapp?
V1 - Speed at which we continue the takeoff even if we have an emergency
V2 - Climb speed that ensures sufficient aircraft control
Vref - Reference speed for approaches, plan to cross threshold at 50’
Vapp - Approach speed (Vref with additives for wind, gusts, icing, etc.)
How does dihedral help in a single engine situation?
The dihedral angle assists in:
1. Increases stability
2. Improving lateral control,
3. Enhancing the aircraft’s handling characteristics in a single engine situation
What are some characteristics of swept wing aerodynamics?
Delay the shock waves and accompanying aerodynamic drag rise when flying near the speed of sound
Result:
1. Increased critical Mach number
2. Trick the wing into thinking it is flying slower than it actually is (no shockwave)
3. Increased lateral stability
