Introduction to Airplane Performance

Assignment Week 1

1. What is most likely sequence of pressure for the given figure. Ans: b

(a) A > B > C

(b) A < B < C

(c) A = B = C

(d) Cant be said

2. An aircraft is equipped with symmetrical aerofoil. For complete aircraft the lift curve slope is 5

/rad. Stall angle is 12 deg, wing area is 10 m2. What is mass during flight, whereas stall speed is

observed 90 Km/hr. g = 9.8 m/s2, density of air is 1.225 kg/m3. Ans : d

(a) 68707 kg

(b) 5301.4 kg

(c) 23438 kg

(d) 409.06 kg

3. Lift is perpendicular to: Ans : b

(a) Thrust

(b) Free-stream velocity

(c) Chord line

(d) Fuselage reference line

4. In the given figure, Xg, Xc and V are, X-axis of inertial frame, chord reference line and free

stream velocity respectively. What is the correct sequence of flight path angle, angle of attack

and pitch angle? Ans : b

(a) 3, 1, 2

(b) 2, 1, 3

(c) 1, 3, 2

(d) 2, 3, 1

5. Vortices causes: Ans : a

(a) Lift induced drag

(b) Parasite drag

(c) Skin friction drag

(d) Wave drag

6. Rudder is primarily used for: Ans : a

(a) Yaw

(b) Roll

(c) Pitch

(d) To increase drag

7. Aileron is primarily used for: Ans : b

(a) Yaw

(b) Roll

(c) Pitch

(d) To increase lift

8. Elevator is primarily used for: Ans : c

(a) Yaw

(b) Roll

(c) Pitch

(d) To increase lift

9. A typical drag-polar looks like: Ans : a

(a)

CL

CD

(b)

(c)

(d)

10. Induced drag for aerofoil is: Ans : b

(a) Infinite

(b) Zero

(c) Half of finite wing

(d) Depends upon aerofoil

CL

CD

CL

CD

CL

CD

11. For a certain angle of attack, at a given altitude, the lift will be doubled for which combination(s)

of S and V Ans : a, c, d

(a) V2, S

(b) V/2, 2S

(c) V, 2S

(d) 2V, S/2

12. For the following vs curve, which has higher aspect ratio? Ans : a

(a) Plane 1

(b) Plane 2

(c) Both have same Aspect Ratio

(d) Cant be determined

CL Plane 1

Plane 2