Re: [Flightgear-devel] null-FDM and UFO-FDM instrument outages

[S A. <san...@gm...>]

Hi John,

John Denker wrote:
>> I ran into the same problem with using generic instruments when 
>> developing the bluebird over 2 years ago. Some instruments rely on 
>> properties that are only updated by the FDM, and the ufo doesn't.
>>     
>
> That's valuable information. Can you be more specific?
>   
> Can you be more specific?  What nasal are we talking about?
> Which instruments?
>
>   
Sorry, I was attempting to provide hints, rather than the answer to 
everything.

Looking at Aircraft/bluebird/Instruments-3d/alt-2/alt2-3d-b.xml
and Aircraft/Instruments-3d/alt-2/alt2-3d.xml
Comparing the two reveals a dependance on 
/systems/electrical/outputs/instrument-lights in the generic version, 
which I thought wasn't powered without the engine running. Maybe this 
has changed a little in 2 years. Maybe it is running on battery, I see a 
small drain...

2nd.
diff Aircraft/bluebird/Instruments-3d/ai/ai-ufo.xml 
Aircraft/Instruments-3d/ai/ai.xml
includes a reference to 
/instrumentation/attitude-indicator/indicated-pitch-deg
which is not updated by ufo FDM.

3rd:
Aircraft/bluebird/Nasal/bluebird.nas
line# 2361 says position/altitude-agl needs updating,
which upon a second look, appears to no longer be true, as of FG 1.0 it 
does update.

Looking at your screenshot, I see the instruments that would be frozen 
or Off with --fdm=ufo are actually showing good information, so that 
must be from a replay?
It doesn't look as bad as I expected.


> That's an interesting hypothesis.  However, I see nothing in
> vor.xml to support this hypothesis.
>   

I was not looking at vor.

> There are lots of aircraft with no electrical bus.  I would
> consider it a bug in the instrument for it to demand an
> electrical bus and not implement a reasonable default.  This
> should be easy to fix.  Which instruments are you referring 
> to?  
>   

Just the one I mentioned. I thought it would be an indicator that other 
systems may depend on the same or similar workings to function.
Since it appears the ufo now has a battery, but no way to recharge, it 
is not the real problem you are looking for.

Stewart