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GATE 2023 AE – Question 23

Structures · Flight vehicle structures: torsion, bending and shear of thin-walled sections, loads on aircraft · 1 mark · Multiple choice

Consider the four basic symmetrical flight loading conditions corresponding to the corners of a typical V-n diagram. For one of these flight loading conditions, it is observed that (i) the compressive bending stresses have a maximum value in the bottom aft region (see figure) of the wing cross-section; and (ii) the tensile bending stresses are maximum in the upper forward region (see figure) of the wing cross-section. For the preceding observations, select the corresponding flight loading condition from the options given.

source diagram and its labels are reproduced in the attached image.
  1. Positive high angle of attack
  2. Positive low angle of attack
  3. Negative high angle of attack
  4. Negative low angle of attack

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Show answer and explanation

Correct answer: (D) Negative low angle of attack

Explanation

The accepted loading condition is negative low angle of attack (D). Negative bending puts the lower skin in compression and the upper skin in tension. The stated aft-versus-forward extrema distinguish the negative low-angle corner of the V–n envelope; identifying only negative lift is insufficient.

Official GATE 2023 answer key: https://gate2026.iitg.ac.in/doc/download/Answer_keys2023/AE_ANS_GATE2023.pdf