# Aerodynamics Questions and Answers – The Symmetric Airfoil – 1

This set of Aerodynamics Multiple Choice Questions & Answers (MCQs) focuses on “The Symmetric Airfoil – 1”.

1. Is symmetric airfoil with good lift to drag ratio is used for an aircraft wing?
a) True
b) False

Explanation: The symmetric airfoil with good lift to drag ratio is used for an aircraft wing, this will be translated into lower fuel consumption, shorter take-off and landing times, and shorter runways. Airfoil With backward facing will get high lift coefficient.

2. Is fluid flows across the airfoil with a backward facing step?
a) False
b) True

Explanation: The fluid flows across the airfoil with a backward facing step, a vortex region which has a lower pressure will be created. This will reduce the wake region of the symmetric airfoil. The idea of the backward facing step airfoil originates from the idea of dimples on the golf ball where the dimples induce the creation of a small vortex region.

3. Is NACA 0012 is symmetric airfoil?
a) True
b) False

Explanation: The NACA 0012 is symmetric airfoil because the mean camber line and chord line intersect in the same line.so, there is no camber in the NACA 0012 airfoil. That the reason the first and second digits are will become zero, and the thickness of NACA 0012 airfoil is 12 percent.

4. What is the thickness of NACA 0002 airfoil?
a) 3%
b) 1%
c) 0%
d) 2%

Explanation: The thickness of the NACA 0002 airfoil is 2 percent. There is no camber in the NACA 0002 airfoil because of the mean camber line and chord line intersect in the same line, so the position maximum camber in the NACA 0002 airfoil is zero.

5. Is wake behind the airfoil exhibits a continuous vortex?
a) False
b) True

Explanation: The wake behind the airfoil exhibits a continuous vortex shedding pattern below 8 degrees incidence angle of NACA 0002 and below 7 degrees incidence angle for NACA 0012 at remolds number 1000 it exhibits the continuous vortex.

6. How many types the wake structure is classified?
a) 2
b) 3
c) 5
d) 4

Explanation: The wake structure is classified into five different modes according to their pattern obtained from instantaneous and mean vorticity fields by also taking into account the amplitude spectrum of the lift coefficient.

7. How lift is calculated?
a) Perpendicular to the direction of motion
b) Parallel to the direction of motion
c) opposite to the direction of motion
d) relative to the direction of motion

Explanation: An airfoil shaped body moved through a fluid produces an aerodynamic force. The component of this force perpendicular to the direction of motion is called lift. The lift will oppose the motion and it produces the lift.

8. Is upper and lower curvatures are equal in symmetric airfoil?
a) True
b) False

Explanation: The upper and lower curvature are equal in the symmetric airfoil because there is no maximum camber in the symmetric airfoil when compare to cambered airfoil it does not produce high lift, so these are used in the subsonic flights.

9. Is symmetric airfoil produce positive lift?
a) False
b) True

Explanation: A symmetrical airfoil only produces positive lift, when it is at a positive angle of attack that is leading edge is higher than the trailing edge. The air stream splits between top and bottom at the stagnation point which is in front of and below the Centre of nose radius.

10. Is flat bottomed wing is more efficient than fully-symmetrical airfoil?
a) True
b) False

Explanation: The flat bottomed wing is more efficient at low speeds than a fully-symmetrical airfoil with an angle of attack less, so that the reason most of the flat bottomed, under cambered wing uses less power and drag for the same lift.

Sanfoundry Global Education & Learning Series – Aerodynamics.

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