Aerodynamics Flashcards
The four forces acting on an airplane in flight are
lift, weight, thrust, drag
When are the four forces that act on an airplane in equilibrium?
During unaccelerated flight.
What is the relationship of lift, drag, thrust, and weight when the airplane is in straight-and-level flight?
Lift=weight and Thrust=drag
Which statement relates to Bernoulli’s principle?
Air traveling faster over the curved upper surface of an airfoil causes lower pressure on the top surface.
Angle between chord line of the wing and relative wind is
angle of attack
As altitude increases, the indicated airspeed at which a given airplane stalls in a particular configuration will
remain the same regardless of altitude.
The angle of attack at which an airplane wing stalls will
remain the same regardless of gross weight.
In what flight condition must an aircraft be placed in order to spin?
Stalled.
During a spin to the left, which wing(s) is/are stalled?
Both wings are stalled.
How will frost on the wings of an airplane affect takeoff performance?
Frost will disrupt the smooth flow of air over the wing, adversely affecting its lifting capability.
Why is frost considered hazardous to flight?
Frost spoils the smooth flow of air over the wings, thereby decreasing lifting capability.
How does frost affect the lifting surfaces of an airplane on takeoff?
Frost may prevent the airplane from becoming airborne at normal takeoff speed.
One of the main functions of flaps during approach and landing is to
increase the angle of descent without increasing the airspeed.
What is one purpose of wing flaps?
To enable the pilot to make steeper approaches to a landing without increasing the airspeed.
An airplane said to be inherently stable will
require less effort to control.
What determines the longitudinal stability of an airplane?
The location of the center of gravity with respect to the center of lift.
Loading an airplane to the most aft center of gravity will cause the airplane to be
less stable at all speeds.
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.
An airplane has been loaded in such a manner that the center of gravity 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 a stalled condition.
Changes in the center of pressure of a wing affect the aircraft’s
aerodynamic balance and controllability.
What force makes an airplane turn?
The horizontal component of lift.
The amount of excess load that can be imposed on the wing of an airplane depends upon the
speed of the airplane.
Which basic flight maneuver increases the load factor on an airplane as compared to straight-and-level flight?
Turns.
During an approach to a stall, an increased load factor will cause the airplane to
stall at a higher airspeed.
How to figure load factor.
How to figure total load.
Bank angle compared to G’s Chart
Weight x load factor = total load
In what flight condition is torque effect the greatest in a single-engine airplane?
Low airspeed, high power, high angle of attack.
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.
When does P-factor cause the airplane to yaw to the left?
When at high angles of attack.
The angle of attack for a propeller is defined as
The angle between the propeller chord line and the relative wind.
VLE
Maximum landing gear extended speed
VA
Maneuvering speed
VFE
Maximum flap extended speed
VLO
Maximum landing gear operating speed
VMC
Minimum control speed
VNE
Never exceed speed
VNO
Normal operating speed
VR
Rotation speed
VS
Stall speed with clean configuration
VSO
Stall speed with landing configuration
VX
Best angle of climb. most altitude in shortest distance
VY
Best rate of climb. most altitude in shortest time
VG
Best glide speed
What is an important airspeed limitation that is not color coded on airspeed indicators?
Maneuvering Speed (VA)
Upon encountering severe turbulence, which flight condition should the pilot attempt to maintain?
Level Flight attitude.
Which V-speed represents best-angle-of-climb speed?
VX
The speed at which a single flight control can be moved, one time, to its full defection without risk of damage to the aircraft is
maneuvering speed.
White ARC
Flap operating range.
Lower limit of white ARC
Power-off stalling speed with flaps and landing gear in the landing position. (VSO)
Top of white ARC
Maximum flap extended speed (VFE)
Green ARC
Normal operating range.
Lower limit of green ARC
Power-off stalling speed specified configuration
Top of green ARC
Maximum structural cruising speed (VNO)
Yellow ARC
Caution range
Red radial line
Never exceed speed (VNE)
max speed the airplane can be operated in smooth air.
Greatest vortex strength
Heavy, clean, and slow.
Wingtip vortices are created only when an aircraft is
developing lift.
Wingtip vortices created by large aircraft tend to
sink below the aircraft generating turbulence.
When taking off or landing at an airport where heavy aircraft are operating, one should be particularly alert to the hazards of wingtip vortices because this turbulence tends to
sink into the flightpath of aircraft operating below the aircraft generating the turbulence.
the condition that requires maximum caution when avoiding wake turbulence on landing is a
light, quartering tailwind.
When landing behind a large aircraft, the pilot should avoid wake turbulence by staying
above the large aircraft’s final approach path and landing beyond the large aircraft’s touchdown point.
When departing behind a heavy aircraft, the pilot should avoid wake turbulence by maneuvering the aircraft
above and upwind from the heavy aircraft.
When landing behind a large aircraft, which procedure should be followed for vortex avoidance?
Stay above its final approach flightpath all the way to touchdown.
How does the wake turbulence vortex circulate around each wingtip?
Outward, upward, and around each tip.
What is ground effect?
The result of the interference of the surface of the Earth with airflow patterns about an airplane.
Floating caused by the phenomenon of ground effect will be most realized during an approach to land when at
less than the length of the wingspan above the surface.
What must a pilot be aware of as a result of ground effect?
Induced drag decreases; therefore, any excess speed at the point of flare may cause considerable floating.
Ground effect is most likely to result in which problem?
becoming airborne before reaching recommended takeoff speed.
