
I will explain assumptions I have made:

        All global vars, such as Alpha, Alpha_dot, Density, Altitude, so on,
        have correct values in the moment cherokee functions are called.

        Body coord system is defined as follows:
                X_body  -> from cg to nose
                Y_body  -> along right wing
                Z_body  -> "down" (to make right coord system)
                All forces and moments act in CG.

                If strange behaviour is experienced, (like impossibility of level
                flight), it is probably misused coord system. Let me know and fix
                the error.

        All controls are in the range [-1.0, 1.0] If it is not so, values in
        cherokee_aero.c on lines 119-121 should be changed acordingly. If
        commands appear to be oposite, this is the place to change sign
        convention.

        Engine controls are in range [0.0, 1.0] (I found out later that lower
        bound is -0.2, so I added fabs(). I know, it is dirty and phisiclly
        wrong, but it was simply the fastest way to deal with it).

        All initialization files are *.ic:
                mass = 74.53 slugs
                Ixx  = 1070  slugs
                Iyy  = 1249  slugs
                Izz  = 2312  slugs
                Ixz  = 0.0   slugs
        above changes are writen in *.ic included in cherokee.zip. However,
        other data in *.ic files are not changed in any way.

        aditional properties: (if needed)
                S    = 157.5 ft^2   -> wing area
                b    = 30.0 ft                 -> wing span
                Ar   = 5.71                        -> aspect ratio
                c    = 5.25 ft                -> midspan chord


Once more: Source are TOTALY UNCHECKED. I hope it will work, but I do not
dare to claim that ewerything will work first time you compile it.

Good Luck!
Gordan
gsikic@public.srce.hr


PS

Work to be done (for myself):
        Landing gear (it is just navion_gear.c copied for now, these are similar
        class of aircraft, so it should work),
        Alpha_max is still undone,
        Spin (if I find any references concerning simulating spin),
        Efect of ground,
        Flaps,
        .......

