
Introduction

Today an aircraft has to fulfil many different requirements and constraints to be effective and costfavourable.
According to a preliminary sizing process for aircraft, introduced by LOFTIN 1980, at first
five major requirements will be solved and second the coincide of it result the definite aircraft parameters.
Reqirements
1. landing field length
This requirement gives an upper value of the wing loading m_{MTO} /S_{W}.
Needed values are the maximum landing lift coefficient c_{L,max,L} and the landing field
length s_{LFL} according to JAR / FAR.
2. takeoff field length
Requirement takeoff field length gives a minimum value of the ratio takeoff thrust to weight over wing loading.
Input values are the maximum takeoff lift coefficient c_{L,max,TO} and the takeoff field
length s_{TOFL} according to JAR / FAR.
3. second segment climb
The second segment climb gives a minimum value of the ratio takeoff thrust to weight. Input is the lift to drag
ratio L / D .
4. missed approach climb
The missed approach climb gives a minimum value of the takeoff thrust to weight ratio. Needed valus are the lift
to drag ratio L / D and the ratio landing to takeoff mass m_{L} / m_{
MTO}.
5. cruise
The cruise requirement gives a minimum of the ratio takeoff thrust to weight over wing loading. Input values are
the Mach number Ma, the design liftcoefficient c_{L,Design} and the maximum lift to
drag ratio (L / D)_{max}.
Coincide of Parameters
All requirements yield a graph to a two dimensional matching chart.
Figure 1: matching chart
example Wing loading m_{MTO} /S_{
W} and the take off thrust to weight ratio T_{TO} /m_{MTO} g
can be determined and further the parameters: maximum takeoff mass m_{MTO}, operating empty
mass m_{OE}, fuel mass m_{F} and wing area S_{W}.