Airplane Stability and Control(Northwestern Polytechnical University)mooc慕课答案2026年版满分测试WYC

对应课程:点击查看
起止时间:2020-09-15到2020-12-28
更新状态:已完结

1. Introduction, Basic Concepts and Definitions Quiz 1

1、 The AOA response of an aircraft after being disturbed is given below. The airplane is statically , and dynamically .

A:stable, stable
B:stable, unstable
C:unstable, stable
D:unstable, unstable
答案: stable, unstable

2、 For the International Coordinate System, x-axis points from CG to the nose, and y-axis points from CG to the right. According to the right-hand system, the z-axis points downward. For the USSR coordinate system, x-axis points from CG to the nose, and y-axis points upward. According to the right-hand system, the z-axis points .

A:upward
B:downward
C:to the left
D:to the right
答案: to the right

3、 The average Cooper-Harper rating of an aircraft is 4.5, it belongs to flying quality.

A:Level I
B:Level II
C:Level III
D:Uncontrollable
答案: Level II

4、 According to the sign convention in this course (international coordinate system), roll to the right about the x-axis is , and yaw to the left about the z-axis is .

A:positive, positive
B:negative, positive
C:positive, negative
D:negative, negative
答案: positive, negative

5、 If the side force acting on the rudder is left (negative), this side force will generate a yawing moment.

A:left
B:right
C:upward
D:downward
答案: right

6、 Rudder locates aft of CG, therefore, a left rudder force will generate a right yawing moment.If the lift acting on the horizontal tail is upward (positive), this tail lift will generate a pitching moment.

A:nose-up
B:nose-down
C:right
D:left
答案: nose-down

7、 Which category of flight phases has the highest flying quality requirement?

A:Category A
B:Category B
C:Category C
D:Category D
答案: Category A

8、 Which of the following aircraft belong to class IV?

A:F-22
B:A-10
C:C-130
D:B-2
E:A320
F:F/A-18
答案: F-22;
A-10;
F/A-18

9、 Which flight phases belong to Category A?

A:Takeoff
B:Landing
C:Air-to-Air Combat
D:Formation
E:Cruise
F:Aerobatic
答案: Air-to-Air Combat;
Formation;
Aerobatic

10、 According to the Cm ~ CL figure, the aircraft is longitudinally stable before stall.

A:正确
B:错误
答案: 正确
分析：According to the longitudinal static stability criterion, for a positive AOA disturbance, if a nose-down (negative) pitching-moment is generated, it is longitudinal static stable. Before stall, as AOA increases, CL increases, so Cm ~ AOA, like Cm ~ CL, has a negative slope, therefore, it is longitudinally stable.

11、 and are the same coefficient.

A:正确
B:错误
答案: 错误
分析：Cl is the rolling moment coefficient while CL is the lift coefficient.

2. Longitudinal Static Stability Contributions Quiz 2

1、 Which of the following factors is not related to the tail contribution on longitudinal static stability.

A:Horizontal tail area
B:Distance between CG and horizontal tail aerodynamic center
C:Downwash angle of the horizontal tail
D:setting angle of the horizontal tail
答案: setting angle of the horizontal tail

2、 Wing contribution on longitudinal static stability depends on CG location, CG moves forward, the stability 。

A:decreases
B:increases
C:doesn’t change
D:depends on Mach number
答案: increases

3、 Most of the wings use positively cambered airfoil, the zero-lift pitching moment Cm0 is .

A:positive
B:zero
C:negative
D:depends on AOA
答案: negative

4、 Horizontal tails increase the longitudinal stability, while canards the longitudinal stability.

A:increase
B:don’t affect
C:decrease
D:[ \ ]
答案: decrease

5、 Which of the following parameters is not affected by the propeller slipstream?

A:local dynamic pressure
B:local lift
C:local drag
D:engine power
答案: engine power

6、 For a given flight condition, which of the following parameters are related to the longitudinal static stability?

A:Wing camber
B:Tail volume ratio
C:CG location
D: Lift coefficient
E:Downwash angle
F:Tail dynamic pressure ratio
答案: Tail volume ratio;
CG location;
Downwash angle;
Tail dynamic pressure ratio

7、 Which of the following parameters are related to the pitching moment generated by the engine?

A:Engine type
B:Engine setting angle
C:Engine thrust
D:Engine position
答案: Engine type;
Engine setting angle;
Engine thrust;
Engine position

8、 The wing has a stabilizing effect on longitudinal static stability.

A:正确
B:错误
答案: 错误
分析：The wing contribution depends on the relative positions of CG and wing aerodynamic center. If CG is ahead of ac, the wing contribution is stabilizing. While if CG is aft of ac, the wing contribution is destabilizing.

9、 Neutral point is the CG location where the aircraft is neutrally stable.

A:正确
B:错误
答案: 正确
分析：The longitudinal static stability of the aircraft is closely related to the CG position. When CG moves forward, longitudinal stability increases, while when CG moves aft, longitudinal stability decreases. Therefore, there is a CG position corresponds to neutrally stable, which is called neutral point.

3. Longitudinal Control and Trim Quiz 3

1、 For a given aircraft, if the control effectiveness of elevator increases, the most forward CG location will

A:move forward
B:move aft
C:remain unchanged
D:[ / ]