Glide Polar Graphs Quiz: Same Glide and Flight Manual

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Questions and Answers

Which force counters gravity during straight-and-level flight?

Thrust

Lift (correct)

Drag

None of the above

What happens to the potential energy of a glider as it glides downward?

It is converted into lift

It is converted into thrust

It is converted into drag

It is converted into kinetic energy (correct)

Which type of drag increases with the square of speed?

Induced drag

Form drag (correct)

Interference drag

Skin friction drag

What is the force called that results from the difference in pressure between the front and back surfaces of an object?

Form drag Signup and view all the answers

What is the type of drag caused by the roughness of the glider's surfaces?

Skin friction drag Signup and view all the answers

Which type of boundary layer generates more skin friction drag?

Turbulent boundary layer Signup and view all the answers

Which axis does yaw movement represent?

Vertical axis Signup and view all the answers

What controls the pitch of the glider?

Pulling the stick back or pushing it forward Signup and view all the answers

What does positive dynamic and static stability mean?

The glider tends to return to equilibrium and reduces its oscillations with time Signup and view all the answers

Which one of the following wing planforms is known for minimizing induced drag?

Elliptical Signup and view all the answers

What is the purpose of a turbulator on a glider wing?

To eliminate separation of the boundary layer Signup and view all the answers

What causes interference drag on a glider?

Varied currents of air meeting and interacting Signup and view all the answers

What is the consequence of a turbulent boundary layer on a glider wing?

Increased skin friction Signup and view all the answers

Which type of wing design is more efficient in terms of lift-to-drag ratio (LD), but has the drawback of potentially causing loss of control with little warning?

Elliptical Wing Signup and view all the answers

Which wing design creates more induced drag than an elliptical wing of comparable size?

Rectangular Wing Signup and view all the answers

Which wing design is most frequently found on gliders and produces less drag than the rectangular wing, assuming equal wing area?

Tapered Wing Signup and view all the answers

What is the primary consideration for choosing a tapered wing over a rectangular wing?

Drag Signup and view all the answers

Which of the following is the correct definition of the glide polar graph?

A graph that shows the glider's glide ratio at different airspeeds within its flight envelope Signup and view all the answers

What is the minimum sink speed?

The airspeed at which the glider loses altitude at the lowest rate Signup and view all the answers

What is the best glide speed?

The airspeed at which the glider achieves its best glide ratio Signup and view all the answers

How does adding water ballast affect the glide polar graph?

Shifts the graph down and to the right Signup and view all the answers

According to Newton’s Third Law of Motion, for every action there is an equal and opposite reaction. Thus, the air that is deflected downward also produces an upward 3-2 (lifting) reaction.

The downward deflection of air by the lower surface of the wing creates an equal and opposite upward force on the wing Signup and view all the answers

Which factor does not affect the amount of lift generated by an aircraft wing?

Wing surface area Signup and view all the answers

What happens to lift when airspeed is doubled, assuming all other factors remain the same?

Lift quadruples Signup and view all the answers

What is the relationship between the coefficient of lift and the angle of attack?

As the angle of attack increases, the coefficient of lift increases Signup and view all the answers

Study Notes

Forces in Flight

Lift counters gravity during straight-and-level flight.
The force resulting from the difference in pressure between the front and back surfaces of an object is called lift.

Energy of Glider

As a glider glides downward, its potential energy decreases.

Drag

Parasite drag increases with the square of speed.
The type of drag caused by the roughness of the glider's surfaces is skin friction drag.
Turbulent boundary layer generates more skin friction drag.
Interference drag is caused by the interaction between different parts of the glider.

Wing Design and Drag

Elliptical wing planform is known for minimizing induced drag.
A turbulator on a glider wing is used to create a turbulent boundary layer and reduce drag.
A rectangular wing design creates more induced drag than an elliptical wing of comparable size.
Tapered wing design is more efficient in terms of lift-to-drag ratio (LD) but has the drawback of potentially causing loss of control with little warning.
The primary consideration for choosing a tapered wing over a rectangular wing is to reduce drag.