各位航空迷，試一試你能答對多少題？

以下的題目來自科大「MECH1906」於2021-22年度的期中考。我選了一些和飛機原理相關的題目，你們可以答對多少題？
1. Which of the following does NOT directly control the lift and/or drag on airplane?
(A) Fuselage
(B) Flaps
(C) Spoiler
(D) Winglet

2. Which of the following statement about development of aircrafts in the future may NOT be true?
(A) Future aircrafts will be further optimized and the
best and correct configuration will be achived.
(B) Fuel efficiency will be further improved.
(C) Noise of aircrafts will be further reduced
(D) Emission of pollutants will be further reduced

3. Airplanes experiences both lift and drag during flying. Which of the following description about
drag is NOT true?
(A) Lift is due to higher pressure at bottom surface of an airfoil and lower pressure on top
surface.
(B) Total drag on an airplane is due to both induced drag and parasite drag
(C) Induced drag is inherent with lift.
(D) Parasite drag can be eliminated by optimized aerodyanmic design.

4. Which of the following statement may NOT be true about airfoil and angle of attack?
(A) An airfoil is a 2-D cross-section of a 3-D wing;
(B) The airfoil-shaped component moving through air generates aerodynamic forces such as lift
and drag
(C) The angle of attack is defined as the angle between the chord line and the relative wind;
(D) When angle of attack is zero, there will be no lift force.

5. Which of the following BEST describes the feature that an aircraft wing and a propeller blade of
a helicopter share in common?
(A) Both of them are in same size
(B) Both of their cross-section is airfoil shape
(C) Both of them must be made of composites
(D) Both of them must be twisted to have variable pitch angle

7. Aerodynamics forces on a flying object is very important for us to understand the principles behind
various aerospace vehicles. Which of the following statement is INCORRECT about the nature of
aerodynamics forces?
(A) An airfoil shape is required to generate aerodynamic forces on a flying object;
(B) At any point of the airfoil surface, there is surface pressure working perpendicular to the surface and
surface shear along the tangential direction;
(C) Due to the resultant aerodynamic force, it impossible to have zero net force on a flying object
(D) The overall resultant aerodynamic force has a tendency of rotating the flying object

8. Lift-to-Drag ratio L/D (defined as the ratio of lift force to drag force) is a very important design
parameters for airplanes Which of the following statement may not be true ?
(A) Lift-to-Drag ratio L/D is also equal to the ratio of life coefficient to drag coefficient
(B) If the lift-to-drag ratio is 10, it means that every one Newton of thrust to overcome one
Newton of drag, the wing is lifting 10 Newton of weight.
(C) Lift-to-drag-ratio can continue to increase even after stalling occurs.
(D) With a larger Lift-to-Drag ratio L/D , an airplane can fly for longer range

9. Which of the following may lead to INCREASE of drag forces on an aircraft? Assuming everything else
of the aircraft remains the un-changed.
(A) Extend the landing gear in the air before landing;
(B) Reduce aircraft flying speed;
(C) Smooth out the angle at junction between the wing and fuselage;
(D) Smooth the aircraft surface roughness

我冇讀過工程、冇查過維基，嘗試作答如下：

1D　2A　3D　4D　5B　7A　8C　9A

幾時開估？