Airfoil Selection MCQs : Here you will find MCQ Questions related to "Airfoil Selection" in Aircraft Design. These Airfoil Selection MCQ Questions Will help you to improve your Aircraft Design knowledge and will prepare you for various Examinations like Competitive Exams, Placements, Interviews and other Entrance Exmaniations
vehicle size was selected so that tunnel blockage did not exceed?
Explanation: The available wind tunnel test section cross sectional area was 2 feet × 3 feet; therefore, a restriction was imposed on the span of FWMAV to avoid solid blockage and wake blockage errors during wind tunnel experimentation. Hence, vehicle size was selected so that tunnel blockage did not exceed 5%.
Model span was kept within ________ of test section width
Explanation: Model span was kept within 20% of test section width so that wing tip vortices could grow easily and 3D flow conditions are recorded.
For trim flight, pitching moment coefficient at zero angle of attack, Cm0, must be?
D. None of the above
Explanation: For trim flight, pitching moment coefficient at zero angle of attack, Cm0, must be positive, whereas, for longitudinal stability, aerodynamic center must be aft of CG.
The cross-sectional shape of wing is called _____
Explanation: Wings are designed with airfoil cross-section. Engine inlets are typically circular in cross-sections. Camber and chord are parameters of an airfoil.
The model was fabricated using EPP foam with density __________ using CNC machine.
A. 30 g/L
B. 40 g/L
C. 50 g/L
D. 50 g/L
Explanation: Accuracy of a tested model is of prime importance if an accurate prediction of aerodynamic and stability parameters are desired. The model was fabricated using EPP foam with density 30 g/L using CNC machine
If an airfoil is operating at Mach 1.1, then it is working in _____
A. transonic range
B. supersonic range
C. subsonic range
D. hypersonic range
Explanation: Based on mach number flow can be subsonic, supersonic, transonic or hypersonic. If flow mach number is <0.8 then it is subsonic. If flow mach number is >0.8 but <1.2 then, it is transonic. If flow mach number is in the range of 1.2-5.0 then, it is supersonic. If flow mach number is <5.0 then, it is hypersonic.
Pressure on the upper surface is _________
A. higher than lower surface
B. lower than lower surface
C. always 30.25 times lower surface
D. always same
Explanation: Pressure on the upper surface of an airfoil is lower than that of the lower surface. This will provide pressure difference which will generate lift force. Pressure will be the same if AOA is 0° in case of symmetric airfoil.
Which of the following is correct?
A. Lift produced by an airfoil is always equal to weight
B. Drag by sphere is less than that of produced by an airfoil for similar conditions
C. Drag by sphere is more than the drag produced by an airfoil for similar conditions
D. Drag by sphere is equal to the drag produced by an airfoil for similar conditions
Explanation: Lift produced is not always same as weight. Sphere is a 3D object. Drag produced by sphere will be more due to increased friction and 3D effects. An airfoil is 2D shape which will have less drag as compare to sphere for all similar conditions.
Which of the following is not an application of an airfoil?
A. To provide lift
B. To provide lift co-efficient
C. To provide streamlined flow
D. To provide thrust for acceleration
Explanation: In an aircraft, engines are used to provide thrust for acceleration. Airfoil is used to provide lift, to improve certain flow characteristics. Streamlined flow is also produced by an airfoil.
What do you mean by double cambered airfoil?
A. Airfoil with flat lower surface
B. Airfoil with curved upper and lower surface
C. Airfoil with flat upper and lower surface
D. Only upper surface is curved
Explanation: Traditionally, airfoils with only curved upper surface and flat bottom was termed as camber airfoil. However, if both surfaces are curved then, it is called a double cambered airfoil. In now days not most people use this terms but at some places it is still in use.