Simulation model

The model is a six degrees of freedom (6 dof) digital model with a linear aerodynamics model. The aerodynamics data is copied from “AIAA2000-0360.pdf”.
The program is written in PHP and is server based – for this specific application at an intranet server. It is run by use of a web client, in this case Windows Explorer.

Variable list and standard plots

The explanations below are based on “general understanding” of aeronautics terminology, in order to avoid the mathematical complications of the exact technical/scientific definitions.

wx, wy, wz aircraft’s angular velocity (rotation rate) rel. to Earth, around aircraft axis’.
Positive directions: roll right, nose up and nose to the right resp.
nx, ny, nz load factor in aircraft’s axis directions
Positive acceleration => negative load factor.
Alt altitude (geometric)
VT true airspeed
Ve equivalent airspeed
VG ground speed
alfa angle of attack
Positive alpha => wind from below.
beta sideslip angle
Positive beta => wind from the right.
gamma path angle - angle between aircrafts velocity vector and a horisontal plane
Positive gamma => climb.
fi, teta, psi aircraft’s attitude angles (euler angles in roll, pitch and yaw resp.) rel to Earth
Positive angles: Right wing down, nose above horizon and compass directions respectivly.
da, de, dr ailron-, elevator- and rudder angles
Positive directions: Left ailron down (right roll command), elevator down (nose down command),
rudder to the left (nose left command).
deL, deR left and right elevator-half angles
Positive directions: elevator down (nose down command)
dteL, dteR elevator trim tab angle, Left and Right.
Positive directions: Tab trailing edge down
df Flap angle, flap down is positive.
dthr thrust as time history, average, dthr =1 is full power, outside plot if dthr > 0.6
Fy_fin Fin load in y-direction, force to the right is positive.
Fz_stL Load on left stabilizer half in z-direction, force "downwards" is positive.
Fz_stR Load on right stabilizer half in z-direction, force "downwards" is positive.
Fz_stab Load on stabilizer in z-direction, force "downwards" is positive.
Fz_stab=Fz_stL+Fz_stR.
w_north
w_east
w_down 		North/South -component of gust. Positive means that the air moves towards North.
East/West -component of gust. Positive means that the air moves towards East.
Vertical component of gust. Positive means that the air moves downwards.
beta_fin As beta, but at position of fin (instead of cg).


The simulation result is presented graphically. There are five standard plots. They can easily be changed or completed and new plots can be added. In most cases only plot 1-4 are of interest.
Plot 1 shows pitch variables vs time
Plot 2 shows (mainly) yaw/roll variables vs time
Plot 3 shows the flight path in two views - from above (top) and from south (bottom).
Plot 4 shows the applied wind gusts and (exept for the first version) beta_fin, all vs time.
Plot 5 shows the flight path with an aicraft like symbol, that makes it possible to see the approximate values of attitude angles and - in some cases - angles of attack and sideslip.
Plot 6 shows the evaluated result from simulated flight in stochastic, normal distributed gusts in three tables: Table a for gust characteristics, b for flight conditions and c for statistics.

Data in the plots are presented in SI units with radian (r or rad) as angle unit.
Exeption: Plot 6, where angles are presented in degrees.