[Flightgear-devel] Consistent aircraft states

[David M. <dav...@gm...>]

On 12/10/2007, dave perry <ski...@mi...> wrote:

> Welcome back.  I am the one that made all the changes to the Warrior.
> Starting directions and keyboard switch equivalents are under the help
> menu-Aircraft help, just like with the pa24-250.  It was after you had
> commented on how you liked what I had done on the pa24 that you sent me
> your pictures and asked if I wanted to continue developing the Warrior,
> so I used the pa24 nasal work as a starting point for implementing the
> Warrior electrical system and switches.

You did a great job on it -- I'm very impressed.

> I still consider the Warrior your aircraft and had communicated to you
> off list in mid August that I had made updates and changes.  I asked for
> feedback in that note.  I assume that you did not disable or bypass the
> nasal implemented switches with the above change.

No, but I did migrate some of the property settings out of the Nasal
script and into the XML settings file.

> I am clearly one that prefers to  start with the brakes set and all
> switches off as that is the way every real flight  starts.

(An aside: In my experience, it's rare that the parking brake is on
when a real light plane is parked, because line staff wouldn't be able
to move it around without gaining inside access -- in fact, when I get
out of the plane at a remote airport, the first question from line
staff is usually not "do you need fuel?" but "is the brake off?".
Normally, a plane on an apron is chocked, while a plane in longer-term
parking is tied down.)

> But I also
> see the advantage of having an easy  option to start in the air with
> switches and fuel valve set for an approach.  Perhaps with a little more
> effort, there is a way to accomplish both.

Here are a few usability guidelines that might help:

1. Consistency - all aircraft should start in same default state as
far as possible (obviously, a glider doesn't have an engine), so that
a user isn't surprised when switching aircraft types.

2. Configurability - it should be not only possible but very easy for
a user to override the default state without editing XML or Nasal
files.

3. Simplicity - the default state should be the easiest one for new
users.  Experienced users  will have an easier time changing the
default.

I suggest that we introduce a new global property, such as
/sim/start-state, which can be set to (say) "parked", "in-air", or
"idling".  The configuration files for every aircraft could respect
that property, so that if you set it to "parked", *every* aircraft
(even the default 172) would start parked, etc. (we could even put it
on the apron instead of the runway if we add parking coordinates to
the airports file).

I think "idling" should be the default the first time someone runs
FlightGear, since it's standard with all flight sims and by far the
easiest for new users, but one menu selection should be able to switch
to "parked" for people (like you) who prefer to go through the startup
and taxiing routine every time.


All the best,


David