Weight Estimation

Aircraft Weight

The weight estimation for an aircraft is very important. From a control point of view the weight distribution and CG location is quite significant because of the finite amount of aerodynamic control power that is available from the flying aircraft - (notice in commercial planes which are not full you are assigned a window seat without asking)

The preliminary design starts when the specifications are decided. The preliminary design focuses mostly on aircraft performance and preliminary sizing.

It has to start with the weight since the aerodynamic engineer wants to know how much he has to lift and drag. The structural engineer can start his work on after the aerodynamic designer tells him about the aerodynamic load distribution.

How do you start to asses the weight of a plane that is to be designed ?- the first prototype must be the only one and has to be successful.

While companies that design and manufacture planes have their own data base and expert knowledge, new operations need to estimate the weight of the aircraft by adding weights of components obtained by statistical analysis of currently flying examples in the same class of aircrafts (and developing their own thumb rules).

One way to estimate the weight of aircraft is the consideration of weight fractions. If

Dividing the above expression by the total weight will yield weight fractions.

The empty weight itself can be broken into:

Components: It is possible to know the weight of the complete aircraft from Wikipedia or Jane's All the World Aircraft but difficult to know about the distribution. We can use these tables as suggestions for out type of aircraft.