Question

Why dorsal fins are used?

(a) To improve tail-effectiveness at high slide slip angle

(b) To reduce tail-effectiveness at high slide slip angle

(c) Similar to horizontal tail

(d) Provides lift to fly

This question was posed to me during an interview.

Enquiry is from Tail Geometry and Arrangement in chapter Airfoil and Geometry Selection of Aircraft Design

Answer 1

Correct answer is (a) To improve tail-effectiveness at high slide slip angle

To explain: Dorsal fins are small attachments at the vertical tail. Dorsal fins are used for improving tail effectiveness at high slide slip angle. Dorsal fins are not similar to horizontal tail. Lift is primarily provided by wings.