Discussion
Match each lateral mode with its typical behaviour.
List I
A. Dutch roll
B. Roll subsidence
C. Spiral
List II
P. Time constant of a few tenths of a second
Q. Oscillation of a few seconds, lightly damped
R. Time to double amplitude of tens of seconds
Select the correct match.
Answer: A
Dutch roll is the oscillation, roll subsidence the fast time constant and the spiral the slow divergence, so A-Q, B-P, C-R. The numbers are worth carrying: a Dutch roll period of three to six seconds with a damping ratio around 0.1, a roll time constant of 0.2 to 0.5 seconds, and a spiral that doubles in twenty seconds or more when it is divergent at all. Swapping the first two confuses an oscillation with a decay, and attributing tens of seconds to the Dutch roll would make it as slow as a phugoid.
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development