Question

The empty weight fraction of a jet transport with fixed sweep is given by ______

(a) 1.02*(Wo^-0.06)*1.0

(b) 1.5*(Wo^-0.16)*1.0

(c) 1.09*(Wo^-0.06)*1.12

(d) 1.02*(Wo^-0.06)*1.04

This question was posed to me in a national level competition.

My question comes from Conceptual Sketch Sizing in portion Conceptual Sketch Sizing of Aircraft Design

Answer 1

Right option is (a) 1.02*(Wo^-0.06)*1.0

To elaborate: The design take-off gross weight is W0 = Wcrew + Wpayload + Wfuel + Wempty

The fuel and empty weight are taken as fractions of gross weight and thus following is given as

Empty weight fraction= Wempty / W0 = A*K*(W0) ^c

Where, A and c are constant and dependent of type of Aircraft and K = variable sweep constant

For a typical Jet transport aircraft with fixed sweep, A = 1.02, c = -0.06 and K = 1.0.