No. of Printed Pages: 3 IBAS..OI7I
B.Tech. AEROSPACE ENGINEERING
(BTAE)
Term-End Examination
December, 2016

::JCl44....3
BAS-017 FLIGHT MECHANICS
Time 3 hours Maximum Marks: 70
Note: Attempt Beven· questions in all. Question no. 1 is compulsory. Attempt any six questions from the remaining questions. Use of scientific calculator is permitted.


1. Explain the following terms and their importance:

Trim Tab

Wing dihedral

Rudder power

2. Derive the expression for pitching moment curve slope and pitching moment at zero lift for stick-free longitudinal case, i.e., for and Cm0 for complete aircraft.

3. Define adverse yaw. How can it be taken care of Explain the design criteria for rudder in adverse yaw.

Define weathercock stability with the help of sketches. 2

4. Define stick-fixed and stick-free neutral points. Calculate stick-fixed and stick-free neutral points using the following data:


Xac 0.25 C CL 0.11 per deg

C 1.7m CL 0.091 per deg

Lt 7m nt 0.95

Sw 30m Cm 0.12 per rad

St 4.5 m Ch — 0.016 per rad

ARw 8 Cho — 0.027 per rad

CL 0.25 per rad

5. Define dihedral effect. How does dihedral affect the lateral stability of the aircraft? 2+4

Derive the expression for aileron power. 4

6. Define stick force gradient and explain its importance. How can, you estimate maneuver point (stick-fixed) experimentally?

7. Define the following terms: 5x2

Damping in yaw

Restoring characteristics

Elevator effectiveness

Trim condition

Stability

8. Write short notes on the following: 2x5

Methods of Aerodynamic Balancing

Control of Wing Torsional Diversion

9. Define static stability. Calculate Cm0 (pitching moment coefficient at zero lift) and Cm (pitching moment curve slope) for complete aircraft for stick-fixed condition using the following data:

CL0w 0.31 Cmacw -0.11

CL 0.11 per deg Cm0fus — 0.01

CL 0.091 per deg Cm0fus 0.12 per rad

Xc8 0.29 C Sw =30 m2

Xac 0.25 C St 4.5 m2

ARw 8 lt 5.5 m

iw 1.1 deg nt 0.92

it 1.1 deg

C 1.9 m