http://wiki.flightgear.org/index.php/Im ... er_Realism,
and a devel list reply by Ian :
I'll see if I can help a bit with the FG ridgelift implementation.
Which glider has the best flight model and instruments? Ridgelift only really pays off when you have a decent glider.
I've expanded the wiki stub http://wiki.flightgear.org/index.php/Im ... er_Realism to at least create a section for each area
that needs a decent solution to have a competitive soaring capability in FlightGear.
The bits I worked on for FSX were ridgelift, the TE and netto variometers, the IGC logger, and the flight model to upgrade the stock
glider (DG808S). The default capabilities of FSX for soaring were very poor (unrealistic glider flight model, no ridge lift, only an
uncompensated rate-of-climb vario). Peter Luerkens programmed CumulusX! which provides the thermals.
Cheers,
B21 / Ian Forster-Lewis
p.s. can you link directly to external images in the wiki, or do you have to upload all images to the actual wiki server?
In my honnest opinion, the gliders in FG still need a lot of improvements, but the ASK21 is yet in a good, usable state. It has a compensated, audio variometer, that works quite well. I don't know if it i really realistic, but this audio vario helps me a lot in thermals and ridge.
http://wiki.flightgear.org/index.php/Schleicher_ASK_21
Gauges
Unfortunately it is not possible to create a decent glider by simply copying across existing instruments from a power aircraft. The minimum instrument set is an altimeter, air speed indicator, and variometer. The variometer (vario) is unique to soaring.
You could check in the flight gear sources, in "(fg-source-path)/data/Aircraft/Instruments-3d/" , and in each glider implementation, to see what currently exist as instruments.
Total energy compensation. If the glider is climbing, a factor can be subtracted from the indicated lift if the glider is decelerating, and the reverse during descent. So if the glider is neither accelerating or decelerating the absolute rate of climb (or sink) will be shown.
I don't know of a FG graphic one, but the ASK21 has an audio one ( see above )
Netto compensation. The design sink rate of the glider at the current airspeed is added to the total energy vario reading, so the variometer actually displays the vertical rate of the air outside the glider. For a perfectly compensated instrument, the vario will show zero in still air regardless of the airspeed of the aircraft
This one would be quite easy to simulate, just by using "wind-from-down-fps" as driving property. this would make a perfect one. Probably too perfect, even.
IGC file logger
To compare flights with others, it helps to have a log of your flight in the 'IGC format'. This is a text file with an agreed format, with some header rows and then one-row-per-timestamp for the lat/long/alt.
I don't know what format is used internally, but flightgear currently features this :
http://fgfs.i-net.hu/modules/fgtracker/
For instance, this is one of my flights with the new ridge lift
http://fgfs.i-net.hu/modules/fgtracker/ ... TID=759405 ( flight details )
http://fgfs.i-net.hu/modules/fgtracker/ ... TID=759405 ( to be seen in google-earth )
As far as I know, every flight made on a public multiplayer server is logged here.
Peter Luerkens programmed CumulusX! which provides the thermals
Do you think Peter would be interested in contributing to FG too ? Or maybe let us see his code ?