Talk:Implementing VNAV support in FlightGear

From FlightGear wiki
Jump to navigation Jump to search

another VNAV procedure which requires the PerfDB is the geographical path decent(i.e w/ECON, it gets all blurry to me here), where the aircraft wants to remain at a given thrust per speed(Idle thus "Econemy"), thrust and speed is binded together here.

someway to implement this, given all the correct input ofcourse. is a simple exponential function(im not very good at math) for the lateral path.

to balance drag and lift with the trajectory path.

these are example where we might quiery our database, what is left is for us to specify the DB file structure and the inputs needed to gather in it(data analysis phase), for our functions.

as you can see, if dividing this project to few abstract ideas it becomes easier.

  • database structure(contains inputs for trajectory function)
  • third party system(that contains this database)

It really involves a few different concepts that are related/connected - i.e. the autoflight system, the FMS controlling it, the CDU and MCP being the frontend to control it, the performance DB being used to look up proper pitch/thrust settings, according to the flight plan and PerfDB etc.
It's normal for such things to take a while to settle, so I wouldn't worry about it. You seem to have switched to the "interesting" stuff pretty quickly - which is why there are still some gaps probably.
Imagine it like a pyramid - the interesting stuff being the top, i.e. your manuals, books and the real aircraft systems (CDU/MCP and FMS) - but we need a solid foundation first.
I would suggest to continue using the "divide & conquer" approach, i.e. build up a repository of VNAV knowledge and come up with the simplest VNAV modes, and see what's missing in FG/JSBSim to implement those, and then take it from there.--User:Hooray

change notes

  • Removal of section "Implementing VNAV support in FlightGear" ( revision 70754, see: [1] ), i thought it was confusing, lacking specifics and need clarification or more legwork first, sorry about that, feel free to undo.

--Flyingsolo (talk) 02:20, 30 October 2014 (UTC)

Related discussions