Aircraft Design Practice Test 10

1. Find tail efficiency if, dynamic pressure at tail and wing is 25Pa and 28Pa respectively.

0.067

0.892

12.54

67.89%

2. Which of the following is incorrect?

Lift is not always same as weight

Stick free and stick fixed are same

Thrust required is not always same power

Uncambered wing lift curve is not same as that of the Cambered

3. Which of the following is not the type of aircraft dynamic mode?

Lateral mode

Flap

Dutch roll

Phugoid

4. An aircraft is operating with CL of 1.5 and has power required of 120W. If we want to reduce the power required by half then, find the value of CL at this power required condition. Consider steady level flight.

1.946

5.59

9.45

2.38

5. Find the value of lift coefficient to ensure power required minimum condition for cruise if CD0/K is given as 0.480.

1.2

7.5

1.7

2.1

6. Determine the corrections or otherwise of the following Assertion [A] and Reason [R]:
Assertion [A]: For longitudinal static stability of an aircraft, slope of moment curve should be negative.
Reason[R]: Positive slope will result in more static stability than negative slope. Hence, slope should be positive always.

[A] is true but [R] is false

Both [A] and [R] are true and [R] is the correct reason for [A]

Both [A] and [R] are true but [R] is not the correct reason for [A]

[A] is false but [R] is true

7. Which of the following is correct to trim an aircraft at positive AOA?

Cm0 < 0

Every value of cm0 will trim at positive AOA

Cm0 will not affect positive trim AOA

Cm0 > 0

8. Find the velocity for minimum thrust required at steady level flight if wing loading is 75N/m² and induced drag factor K is 0.0025. Consider CD0 as 0.02 and density as sea level.

97m/s

6.45m/s

75m/s

120m/s

9. Object shown in the following diagram can be considered as __________

stability can't be guessed from diagram

neutrally stable

statically unstable

statically stable

10. If lift coefficient at thrust required minimum is 0.85 and induced drag factor K is 0.0085 then, find the approximate value of drag coefficient at zero lift.

0.061

0.0061

0.61

6.1