Svf

Question 1

Wx minima for all airspace classifications?

Answer 1

Above 10km
Below 10km
Below 3km

Question 2

What is the SVFR wx minima?

Answer 2

SVFR will only be granted if
CCSG
Grd vis > 1500km
< 140kts

Question 3

What is the SVFR wx minima for TO/LD?

Answer 3

Cloud ceiling > 600ft
Ground vis > 1500km

Question 4

When shall a SVFR not be permitted?

Answer 4

Never at night in the UK.

Other states permit it but is not permissible in UK

Question 5

What is relative airflow?

Answer 5

The direction of the airflow with respect to the wing direction is known as relative airflow. Lift acts 90 degrees to the RAF.

Question 6

What is total reaction?

Answer 6

The resultant of all aerodynamic forces acting on an aerofoil.

E.g. when an AC moves forward, thrust is required to overcome drag, and create a large enough pressure differential on the aerofoil to produce lift. So the total reaction of forward movement of an increase in thrust is a combination of lift and drag.

Question 7

What is the COP?

Answer 7

COP is the ave location of all aerodynamic px acting on a the aerofoil moving through a fluid.

Question 8

what is the boundary layer, transition and separation point?

Answer 8

Referring to aerofoil where boundary layer is the layer between is the laminar flow and free flow air above.
Transition point is where the laminar flow has lost so much of its energy it’s starting to become turbulent.
Separation point is where laminar flow has now detached from the aerofoil.

Question 9

What is parasite drag?

Answer 9

Parasite drag consists of form, friction and interference drag.

Question 10

What is interference drag?

Answer 10

A type of parasite drag. Interference drag describes specifically the drag caused by the mixing of airflow streamlines e.g. the airflow from the wing and the fuselage. The engine pylon and the wing.
Anything which has a junction.

Question 11

What is a chord line and chord length?

Answer 11

Chord line is the imaginary line drawn from TE to LE. The length of this imaginary line is chord length.

Question 12

What is mean dynamic chord?

Answer 12

Chord is also used to describe width as well as length (chord length). In a platform rectangular wing, the MAC = chord. But with tapered and different shaped wings the average chord is calculated and determined as the mean dynamic chord (MAC).

Pitching moments of AC acts on the aerodynamic centre of the MAC

Question 13

Difference between MAC and COP?

Answer 13

While both are found in the aerofoil, MAC refers to the point in which all pitching moments act through, while COP refers to the point in which lift acts through.

COP is the average location of all pressures acting upon a body through a fluid.

Question 14

AOA?

Answer 14

The angle where chord and RAF meet

Question 15

What is wing area?

Answer 15

The size of the wing surface, often measured as aspect ratio.

AR = length / average width (chord)

Question 16

Mean chamber line?

Answer 16

A line drawn from TE to LE equidistance apart from top and bottom of the aerofoil.

Question 17

What is zero lift drag?

Answer 17

Aka profile or form drag. Profile drag is the drag caused by the separation of the boundary layer and the wake caused by the separation.

Therefore this would only occur if the AC was moving through a fluid. Note this type of drag does not relate to lift at all so the question is confusing!

Question 18

What is lift dependent drag?

Answer 18

Aka Induced drag. As question suggests, this is a type of drag that is induced by lift, and at low speeds. Also induced vortices at wing tip.

Question 19

What is adverse px gradient?

Answer 19

This refers to the laminar flow on the upper sfc of aerofoil. The relatively low (dynamic) px on the LE of the upper sfc of flowing backwards to the relatively high (dynamic) px. Like in everything else high likes to move to low and NOT vice versa, this is why laminar flow, when it loses its energy it starts to transition before separating from the aerofoil. The low to high laminar flow is thus called adverse px gradient.

Question 20

How does boundary layer affect zero lift drag?

Answer 20

The boundary layer acts as an intermediate layer that reduces the curvature of the aerofoil, and therefore reduces the lift created. So, a smaller boundary layer gives a greater lifting capability.