Shuttle Fleet Exactly what was changed in Shuttle Fleet's flight model?

[Pipcard]

It has more accurate aerodynamics than the default Shuttle (most importantly, it is compatible with AutoFCS and high AoA holds), but how?

(note to those who don't know: Shuttle Fleet is available here)

 

[PhantomCruiser]

You could try to get in touch with David413, if anyone would be able to help you understand it, it'd be him.

Or maybe shop around for a coder? But then we all do this stuff for free, so it might not be all that timely.

I seem to remember something in the shuttle fleet thread where David was talking about the flight aerodynamics and AutoFCS, but I've got no time (seriously) to dig through that thread to find it. Even then I don't think it was descriptive enough to help out.

 

[Urwumpe]

The main problem was that the default Atlantis only simulates subsonic aerodynamics. At supersonic speeds, it produces too much lift and too little drag.

There is an important quality called maximum lift-to-drag (L/D) to judge the performance of aerodynamic vehicles: At subsonic speeds, like during landing, the Shuttle has a L/D of 4.5 (which is a flying brick with style). At supersonic speeds, high in the atmosphere at high speed, the L/D is only about 1.0-1.6 (Which is much more like a flying brick). That's an important difference, since L/D for example determines how far something glides for every drop in altitude. The default Atlantis would be constantly overshooting unless you plan some extra miles in your re-entry - it needs 3-4.5 times more distance to glide home at constant speed (but the distance is a bit shorter since the Shuttle slows down during a slightly more shallow glide).

In SSU, this all went a little further and more out of control...

 

[martins]

If somebody was sufficiently fed up with the default Shuttle's flight model that they wanted to donate an improved one, I would gladly replace it (and even credit the donor with a line of comment :thumbup: )

Only, the replacement code shouldn't be significantly more complicated, since all the default vessels are primarily meant as code samples to help addon developers. They shouldn't be more difficult to read than necessary, so the balance should be at simplicity rather than accuracy.

 

[Urwumpe]

If somebody was sufficiently fed up with the default Shuttle's flight model that they wanted to donate an improved one, I would gladly replace it (and even credit the donor with a line of comment :thumbup: )

Only, the replacement code shouldn't be significantly more complicated, since all the default vessels are primarily meant as code samples to help addon developers. They shouldn't be more difficult to read than necessary, so the balance should be at simplicity rather than accuracy.

The SSU code would be clearly out then, since it is defined by external CSV tables and pretty complex.

:lol:

But maybe somebody can provide a simpler version that just adds the dimension Mach number to the existing function, with some sample points like "<0.8, 1, 2.0, 5.0, >8.0"

Would need to look if I can calculate this automatically from the SSU data by some Lua...