Properties of the Atmosphere
SECTION 2 :
Aircraft Weight, Geometry, Lift/Drag Coefficient and Engine Thrust Properties.
SECTION 3 :
|The calculation of the performance of a fixed wing aircraft can be
done using a set of simple force equilbrium equations. In most flight
conditions an aircraft will have force equilibrium in all three dimensions.
If a wind axis system is used with vertical being defined at right angles
to the freestream velocity vector then the applied vertical forces will
be a combination of lift, aircraft weight and ground support reaction forces.
For the horizontal axis parallel to the stream direction the applied forces
will consist of a combination of thrust, drag, weight components and ground friction
effects. In the case of a turning aircraft the crosswind axis equilibrium
also needs to be considered as there will be additional inertial forces
generated by centripetal acceleration.
When the aircraft is not in equilibrium then the resulting accelerations
will cause dynamic motion which will need to be analysed by applying the
equations of flight mechanics and control. In this chapter it is assumed
that the aircraft is in equilibrium, or near equilibrium, so that the simpler
aircraft performance equations can be applied. Calculations of take-off
roll, field length, climb rate, climb gradient, ceiling, range, endurance,
turn rate, descent angle and landing roll will be shown using
basic equilibrium equations.
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© Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, 1998-2005.