Question

What will be the total fuel weight fraction for x-number of mission phases?

(a) Wf / W0 = 1 – (Wx / W0)

(b) Wf / W0 = 1 + (Wx / W0)

(c) Wf / W0 = 1 / (Wx / W0)

(d) Wf / W0 = 1 + (Wx / W0)

The question was posed to me in semester exam.

My enquiry is from Conceptual Sketch Sizing in portion Conceptual Sketch Sizing of Aircraft Design

Answer 1

Right option is (a) Wf / W0 = 1 – (Wx / W0)

Best explanation: The fuel-fraction method is used to determine total fuel weight fraction.

According to which if there are x – number of mission phases in mission profile then the total fuel weight fraction is given by,

Wf / W0 = 1 – (Wx / W0)

Since, reserved fuel is not mentioned we can neglect it.