Aerodynamics Flashcards
When an aircraft is rolled, what force is inclined?
Lift
Lift is always perpendicular to the direction of what?
Relative airflow
During a roll, the aircraft is pulled sideways. What is the name for this effect and what is the cause?
Sideslip resulting from the lift being inclined to one side.
What is the secondary effect of a roll and why?
Yaw due to loss of lift resulting in sideslipping which pushes the tail sideways into the air
What is the primary effect of using rudder?
Yaw
What is the secondary effect of applying rudder and why?
Roll because the rudder creates a yaw that increases relative airflow over the wing on the outer side of the turn.
What is the term used to specify the degree of cross sectional curvature of a wing.
Camber
What is the typical critical angle (in degrees)?
15 to 16
What is the name of the type of drag that is greatest at low IAS?
Induced drag
The trim control is used to provide what?
Aerodynamic balance
Flutter of control surfaces is prevented by what?
A mass balance that brings centre of mass of the control surface closer to the hinge.
During takeoff, should flaps be used?
Flaps are used according to manufacturer specifications
What is Vx used to represent and what is the value in a Jabiru J160?
Speed of climb in a max angle climb -60Kts
In a Jabiru J160, what is Vy (max rate climb speed) in Kts?
80
What does VSI stand for?
Vertical speed indicator
Performance is determined by what and what?
Power and Attitude
Lift divided by weight is called what?
Load factor
Stall speed increases by what function of an increased load factor?
The Square root
In a level flight bank, what happens to the load?
Lift has to increase to compensate for being inclined so that the load factor also increases
Turn performance is related to what and what?
Angle of bank and IAS
The lift equation ( CL . 1/2 . Density . V^2 . S ). CL is related to what two properties?
Angle of attack and camber
A slipping right turn (analogous to understeer in a car) causes the balance ball to drift to which side?
Right
A skidding turn (analogous to oversteer in a car) sees the balance ball pushed to which side of the turn? (Outside or inside)
Outside
If the aircraft is skidding when turning should more or less rudder be applied?
Less
If an aircraft is carrying luggage that has been stowed such that shifts the centre of gravity to the aft, will the stalling speed increase or decrease?
Increase
What happens to the angle of attack when a wing encounters a thermal updraft?
It increases as the air is approaching the aircraft from below
If one wing stalls, it may cause the aircraft to roll. The downwards motion of that wing relative to the air increases its angle of attack. What is the term for effect this has on the stall?
Aggravating the stall
Why should ailerons never be used in a stall?
They increase the drag
What control input is used in a stall?
Rudder
What is the correct response to a spin?
Throttle to idle, apply opposite rudder, lower the nose, apply full power to recover lost altitude
How can a pilot distinguish between a spiral dive and a spin?
If the indicated airspeed is low, the aircraft is in a spin. If it’s high, the aircraft is in a spiral dive.
A dynamic accelerated stall is also known as a what? Why might this occur?
High speed stall. Beyond the critical angle a stall will occur regardless of speed.
Beyond the critical angle, is there a speed that can prevent a stall
No
With a faster airspeed the radius of a turn is what
Increased
What is worst for a small aircraft when a nearby larger aircraft is flying slowly, taking off or landing or is flying on a clam day?
Wake turbulence
When taking off after a larger aircraft, you should lift off where (relative to the larger aircraft’s liftoff point)
Before