Question

Cessna 172R has total gross weight of the 1110.98kg with fuel capacity of 210 kg and weight of crew and passenger is 125kg. Find out empty weight fraction.

(a) 775.98kg

(b) 69.84kg

(c) 0.6984

(d) 0.6984lb

I got this question by my school teacher while I was bunking the class.

The origin of the question is Conceptual Sketch Sizing in chapter Conceptual Sketch Sizing of Aircraft Design

Answer 1

Right answer is (c) 0.6984

To explain: Given,

Design take-off gross weight, W0 = 1110.98kg

Crew and payload weight = 125kg

Fuel weight = 210kg.

Here, first we need to find the empty weight and then we can find empty weight fraction.

Now the design take – off gross weight is given by,

W0 = Wcrew + Wpayload + Wfuel + Wempty

1110.98 = 125 + 210 + Wempty

So, Wempty = 775.98kg

Hence, empty weight fraction = (Wempty / W0) = 775.98/1110.98 = 0.6984.