Question

Let’s consider an aircraft has statistically determined aspect ratio of 8.1. Aircraft has canard which gives contribution of 10% for total lift. Determine the aspect ratio of wing.

(a) 9

(b) 0.9

(c) 10

(d) 8.1

I got this question in my homework.

The origin of the question is Wing Geometry-2 in portion Airfoil and Geometry Selection of Aircraft Design

Answer 1

Right choice is (a) 9

Explanation: Given, Aspect ratio statistically ARst = 8.1

Canard contribution = 10%

Here, total lift is not produced by the wing only. Canard is also responsible for it as well.

Hence, wing contribution = total lift – lift by canard = 100% – 10% = 90% = 0.9.

Now, aspect ratio of the wing is given by,

ARw = ARst / wing contribution = 8.1 / 0.9 = 9.