remove a hack and do it properly: if the requested elevation is for some
reason below the surface and the intersection test fails (as it appears
to be the case in EGLL), try again from 10000m ASL
mf: typos
are sharp, as intended. These were are never seen in practice; I
found the problem while looking at 360 degree lift curve graphs
looking for discontinuities.
"jitter" when the aircraft was stopped. This is a fundamental
characteristic of the gear model, and can't be fixed without major
surgery (and not a small amount of blinding insight). But we can at
least clamp it so the value can't change unless the wheel is moving
with a nontrivial velocity (5cm/sec in this case).
there was the situation where four directories contained jst two files,
of which three directories were aircraft related, and one directory contained
test code from Curt that might be better of in SimGear anyhow.
This is just a patch to move a bunch of files to new locations. In case of
local changes to any of them you can do the following:
move replay.[ch]xx from src/Replay to src/Aircraft
move control.[ch]xx from src/Control to src/Aircraft
move ssgEntityArray.[ch]xx from src/Objects to simgear/screen
In addition it has been decided only to use .[ch]xx files in all directories
unless it's contained within an FDM specific directory, in which case the
author is free to do whatever (s)he wants.
In this repspect the following files have been renamed in src/Multiplayer:
tiny_xdr.[ch]pp has become tiny_xdr.[ch]xx
multiplaymgr.[ch]pp has become multiplaymgr.[ch]xx
CygWin/gcc-3.4.4 updates.
I replaced my cygwin compiler with 3.4.4, did a make clean of plib, simgear,
and flightgear, then did a make install of all three. With the included changes,
everything builds fine, and runs fine.
Attached is a patch to add oil temperature to the YASim piston engine
model. This brings to life one of the pa28-161's otherwise 'dead'
guages. It's a pretty simple 'model' based on temperatures and warmup
times I've observed in the labs on auto engines and run through my
dodgy-memory filter. It does the job of populating the guage with
something plausible though.
Using new gcc 4.0 I have some serios warnings about uninitialized
variables, that are used. I created a patch, but I have no idea if it
is possible to do it my way. Can you check this out please?
Erik: I've modified the patch slightly based on the contents of an older
version of hitlist.cxx. I think this is correct now.
it for the B-29). The gear model itself has supported this always,
but there was no interface from the XML file. Should be backwards
compatible. I don't think I broke anything...
I stumbled across two memory errors with two wrong const references to
std::string.
As I fixed that, I also moved aircraft_dir which is only used from UIUC into
UIUC. With that uiuc_aircraftdir.h is empty and can be removed.
I believe I have found the agl hud problems as well as the 'hole' in the
carrier's deck. I spent half the day to reproduce that problem, it did not
occure when you start on the carrier not does it occure with JSBSim and my
really often used testaircraft. So I really need to improove my helicopter
flying qualities.
I was under the impression that *all* FDM's call
FGInterface::updateGeo*Position(..)
so set the new position in the FDM interface. Therefore I had added at the
some code that updates the scenery elevation below the aircraft to *those*
functions.
Ok, not all FDM's do so :/
The attached patch factors out a function computing the scenery altitude at
the current FDM's position. This function is also used in those FDM's which
need to update this value themselves.
Also this patch restores the nearplane setting and uses the current views
altitude instead of the current aircrafts. I think that this should further
be changed to the eypoint's agl in the future.
The agl is again ok in YASim's hud.
Some quite extensive changes to the AIModel code:
1. Mathias has made major changes to the AICarrier code to provide better
alignment of an aircraft on deck with the carrier - this feature is a major
improvement on the existing, but has a bug which might cause it to fail when
the computer carries out other tasks - changing window size is a known
example. This bug is outwith this code.
2. I have made significant changes to the AIShip code to enable a ship the
turn and roll smoothly.
3. I have added some simple AI which enables the carrier to remain within,
or return to, an operating box.
4. An automated turn into wind for flying operations.
5. A simplistic implementation of TACAN within AICarrier. I am in the course
of implementing this as a generic instrument, but this is some time off
completion.
I have prepared a patch that:
- Introduces a FGTileMgr::scenery_available method which asks the tilemanager
if scenery for a given range around a lat/lon pair is already loaded and make
use of that method at some -9999 meter checks.
- Introduces a FGScenery::get_elevation_m method which queries the altitude at
a given position. In constrast to the groundcache functions this is the best
choice if you ask for one *single* altitude value. Make use of that thing in
AI/ATC classes and for the current views ground level. At the current views
part the groundcache is reused if possible.
- The computation of the 'current groundlevel' is no longer done on the
tilemanagers update since the required functions are now better seperated.
Alltogether it eliminates somehow redundant terrain level computations which
are now superseeded by that more finegrained functions and the existence of
the groundcache. Additionally it introduces an api to commonly required
functions which was very complex to do prevously.
Turns out to be a bad interaction between jsbsims crash detection and my
past initialization changes.
The attached patch fixes this by moving crash detection out of the
initialization phase of jsbsim.
I have traced that reset on carrier problem down to several problems. One of
them is the fact that on reset the carrier is updated while the aircraft is
not. That made the aircraft drop down an elevator sometimes. Depending on the
passed realtime while loading some parts of the scenery.
I have introduced the posibility to start directly on the carrier.
With that patch you will have a --carrrier=id argument where id can either be
the pennant number configured in the nimitz scenario or the carriers name
also configured in the carriers scenario.
Additionaly you can use --parkpos=id to select different positions on the
carrier. They are also configured in the scenario file.
That includes the switch of the whole FGInterface class to make use of the
groundcache.
That means that an aircraft no longer uses the current elevation value from
the scenery class. It rather has its own local cache of the aircrafts
environment which is setup in the common_init method of FGInterface and
updated either manually by calling
FGInterface::get_groundlevel_m(lat, lon, alt_m);
or implicitly by calling the above method in the
FGInterface::_updateGeo*Position(lat, lon, alt);
methods.
A call get_groundlevel_m rebuilds the groundcache if the request is outside
the range of the cache.
Note that for the real usage of the groundcache including the correct
information about the movement of objects and the velocity information, you
still need to set up the groundcache in the usual way like YASim and JSBSim
currently does.
If you use the native interface, you will get only static objects correctly.
But for FDM's only using one single ground level for a whole step this is IMO
sufficient.
The AIManager gets a way to return the location of a object which is placed
wrt an AI Object. At the moment it only honours AICarriers for that.
That method is a static one, which loads the scenario file for that reason and
throws it away afterwards. This looked like the aprioriate way, because the
AIManager is initialized much later in flightgears bootstrap, and I did not
find an easy way to reorder that for my needs. Since this additional load is
very small and does only happen if such a relative location is required, I
think that this is ok.
Note that moving on the carrier will only work correctly for JSBSim and YASim,
but you should now be able to start and move on every not itself moving
object with any FDM.
on RPM via a model developed by Vivian Meazza. Add a "boost" output
to the property tree. Fix a bug where MP would be reported "before"
the wastegate clamping.
this is basically the past patch I sent to the list and which should now
really (...!?!?) fix the no ground below aircraft problem.
Reasons:
I understood my remaining thinko I introduced with the prevous patch, and the
same thinko I made in my test cases.
The feedback from the list told me that it should help.
2.
I made YASim query the the ground cache at the wrong place. This one fixed
this, one can now land the bo105 on top of the oracle buildings :)
3.
Is a followup of the scenery center update code: Register the scenery center
transform at the time it is put into the scene graph not at creation time.
4.
I held that part back from the past hitlist patch, because I hoped that it
will be sufficient (and the last one was in fact the biggest part) without.
As some test cases from Melchior showed me, it is not. We have additionally
to the wrong computed transform from the prevous patch some roundoff
problems. This patch adds some small tolerance to for the point in triangle
test.
... may be one even needs to increase the eps value further if starting at
some tile boundaries still fails.
5.
That is a big chunk.
Tested now for two days while hunting the second patch :) .
That is a partial rewrite of the groundcache to use its own datastructures for
that flat scenegraph in the cache. The basic advantage is, what Erik
suggested, to precompute some often used values of these triangles. Also
allmost all computations are now in double precision which should decrease
(hopefully fix), together with a similar tolerance for some point in triangle
tests, the problems with 'no ground below aircraft'.
I am playing with octrees for the groundcache, that will finally solve the
performance problem when high triangular count models end up in the
groundcache. This patch is also some prework for those octrees ...
I have done a patch to eliminate the jitter of 3D-objects near the viewpoint
(for example 3D cockpit objects).
The problem is the roundoff accuracy of the float values used in the
scenegraph together with the transforms of the eyepoint relative to the
scenery center.
The solution will be to move the scenery center near the view point.
This way floats relative accuracy is enough to show a stable picture.
To get that right I have introduced a transform node for the scenegraph which
is responsible for that shift and uses double values as long as possible.
The scenery subsystem now has a list of all those transforms required to place
objects in the world and will tell all those transforms that the scenery
center has changed when the set_scenery_center() of the scenery subsystem is
called.
The problem was not solvable by SGModelPlacement and SGLocation, since not all
objects, especially the scenery, are placed using these classes.
The first approach was to have the scenery center exactly at the eyepoint.
This works well for the cockpit.
But then the ground jitters a bit below the aircraft. With our default views
you can't see that, but that F-18 has a camera view below the left engine
intake with the nose gear and the ground in its field of view, here I could
see that.
Having the scenery center constant will still have this roundoff problems, but
like it is now too, the roundoff error here is exactly the same in each
frame, so you will not notice any jitter.
The real solution is now to keep the scenery center constant as long as it is
in a ball of 30m radius around the view point. If the scenery center is
outside this ball, just put it at the view point.
As a sideeffect of now beeing able to switch the scenery center in the whole
scenegraph with one function call, I was able to remove a one half of a
problem when switching views, where the scenery center was far off for one or
two frames past switching from one view to the next. Also included is a fix
to the other half of this problem, where the view position was not yet copied
into a view when it is switched (at least under glut). This was responsible
for the 'Error: ...' messages of the cloud subsystem when views were
switched.
I have some small updates to the ground cache.
- Remove the usage of dynamic_cast where it is known that the result will be
non null.
- Renormalize the surface normal in double precision.
- Place the groundcaches center at the point it was requested not at the
scenery center. This fixes the problems with JSBSim's trimming together with
the ground cache. Now I am ready to commit JSBSim's ground cache usage.
have a "property" mode as well as the original "binary" mode. The property mode
will allow the remote module to request any set of properties, and it will send
those properties each frame. The remote module can reply with a list of arbitrary
property name/value pairs to update on the FlightGear side.
This is a first stab, so it's not the cleanest, most well concieved code, but it
allows an external module (communicating via a pipe) to have a huge amount of
flexibility in the data in can access and update.
popping up and crashing when the B-29 model is in use. This isn't the
right solution; we should fine the NaN condition. But it's harmless
and allows development with the B-29 to continue.
back, but forgot to put the same fix into the runtime code. Also
added some comments so I don't get confused again the next time I come
through here. :)
I still work on getting the YASim models see the detailed environment
especially the carrier.
I have *forgotten* to initialize and to destruct the ground cache object!
Oooopppss!
currently just returns a lagged normalized value in the range of 0-1 that
is proportional to N1. It's up to the engine gauge to scale to the right
range. This is for lack of a real model of these items so we can have
something to drive the engine gauges.
I have now split out the ground cache functions into src/FDM/groundcache.[ch]xx
Attached are the two files and the patch to integrate that cache into
FGInterface.
The code is nowhere used at the moment, the fdm's need to be updated to use
that ground cache. The JSBSim-dropin.tar.gz from Martins ftp server does this
for example.
The carrier's scenegraph is not yet processed to be visible for ground
intersection testing. So the only benefit up to now is that the api is set
up. Using this I can put the changes to make JSBSim work with that into
JSBSim's cvs. Also I aim to provide Andy a patch to make use of that with
YASim.
I've added two new debug log types for the instrumentation and systems. They
used to use the autopilot debug log, because I couldn't figure out how to
make new log types. Well, now I have figured it out. ;-)
As I had reported on 2004/8/4 00:02:56 ("yasim + bo105 + vrp + @#%$#@ == argh!")
there must be a bug somewhere in YASim, which is responsible for the Bo105
turning around the FDM origin (nose tip) rather than the CG. Some people assumed
that I was just another victim of the "view offset" illusion, but this wasn't
and isn't the case.
Maik Justus (the rotor man) has now supposedly found the bug in YASim[1].
Look at this code in FDM/YASim/Integrator.cpp:35--66:
Stub in hooks for Propeller feathering controls and the turbo prop "condition"
lever.
I added a line in FGFDM.cpp to force control properties to exist if they
don't already. This way you can specify anything you want and find them
in the property browser, otherwise no one else may create them and you are
stuck.
In PropEngine::solve() the code original sets _running = true at the
beginning and then sets running = false at the end. I changed this to
save the current value at the start, set to true, solve(), and then
restore the original value at the end. That way if we start off with
_running = true, we don't have to hack up the calc() routine which wasn't
using the value anyway.
Finally I added some very initial support to shut down a turbine engine
(_running = false) when the condition lever goes to zero.
I have 3 issues that are fixed by this set of patches.
1. In extensions.cxx
#else if !defined( WIN32 ) must be changed by
#elif !defined( WIN32 ) because the text after #else
seems to be ignored
2. banner is not available on windows, only cygwin
3. ANSI escape sequences are not interpreted on the
windows console. We just have garbage that is hard
to read.
the 30 seconds that Maik had originally intended, according to the comment.
This is important for the pending sound and rotor disc changes (and of course
for realism).
"slow/windmilling propeller" regime. I'm happy with the foundations
of the solution, but this hasn't been complete tested yet. The
solution behavior seems fine on the planes I tried.
PistonEngine class has grown an "Engine" superclass. Some other stuff
moved around too, and I cleaned up some property naming while I was in
there. This hasn't been tested very thorougly, hopefully I didn't
break anything.
configure and compile out-of-the-box on a MinGW target:
Use -lSDL instead of -lglut32 on windows builds when --enable-sdl
is set.
Link against alut.dll in addition to openal32.dll.
Replace BSD bcopy() with ANSI C memmove() in a few places. This is
simpler than trying to abstract it out as a platform dependency in a
header file; bcopy() has never been standard.
The ENABLE_THREADS handling has changed to be set to 0 when threads
are not in use. This breaks expressions like #ifdef ENABLE_THREADS.
Replace with a slightly more complicated expression. It might have
been better to fix the configure.ac script, but I didn't know how and
this whole setting is likely to go away soon anyway.
The MinGW C runtime actually does include snprintf, so only MSVC
builds (and not all WIN32 ones) need _snprintf in JSBSim/FGState.cpp
Building on a platform with no glut at all exposed some spots where
plib/pu.h was being included without a toolkit setting (it defaults to
glut). Include fg_os.hxx first.
And when still using glut, glut.h has a bizarre dependency on a
_WCHAR_T_DEFINED symbol. It it's not defined, it tries to redefine
(!!) wchar_t to disasterous effect.
This update contains a change to not overwrite the altitude-ft preset during
"onground" start. The change also prevents a ground trim issue with the
JSBSim fdm when a "reset" is done by FlightGear.
work on the pa28 idle and without creating ridiculous side effects
(like being able to fly the aircraft with the starter motor, heh).
This one looks pretty good for now, pending work on the propeller to
get its low speed drag in line with reality.
reads the /consumables tree for input to determine weights, but
places output only in /engines/engine[n]/fuel-consumed-lbs where
it gets picked up by the Nasal code.
This is a fix for my earlier "Remove some hardcoded dependencies between fdm,
viewer and acmodel" patch. The problem was discovered when testing the
wrightFlyer.
deriving a class and the base class used this type.) Return to using
const char and hope people compiling against earlier versions of plib
have compilers that think typedef const char cchar; char *abc; is equivalent
to const char *abd;
controls in the cockpit vs. which wheels they apply to. FlightGear now
sets /controls/gear/brake-left, /controls/gear/brake-right, and
/controls/gear/brake-parking. It should be up to the FDM to sort out
which wheels under which circumstances are affected by these controls
and ultimately what happens to the physical motion of the aircraft.
places now use sgCartToGeod() instead of rolling their own
approximation. And YASim is now using exactly the same 3D coordinate
system as the rest of FlightGear is.
the core YASim stuff. Mostly cosmetic: whitespace adjustment, dead
code & meaningless comment removal, a little code motion to better
partition the helicopter handling from the original code (no more
giant if() { ... } around the solver). Added a warning to the parser
to try to eliminate the string booleans that crept in.
There should be NO behavioral changes with this checkin.
Here's a new FGSimTurbine module. Changes are:
1. Adds starting and stopping functionality
2. Calculate() now calls other functions, based on the engine's state, which gives more readable code.
Until now turbine engines were always running as long as fuel was available. With this new module the engine defaults to OFF. To start with the engine running, the variable FGEngine::Running must be set to true at sim startup. In FlightGear this is done with --prop:/engines/engine[n]/running=true.
To start the engine (on the ground), first set the starter to ON, i.e. FGEngine::Starter is set to true. In FlightGear this is done by toggling /controls/engines/engine[n]/starter to TRUE. Note that the current FlightGear key binding will not work, as it causes the starter to quit when the key is released. A new key binding is needed, without the mod-up.
When N2 reaches 15% or greater, place the fuel cutoff control to FALSE. This is FGEngine::Cutoff. In FlightGear this is done with /controls/engines/engine[n]/cutoff set to FALSE. The engine will then accelerate to idle. Upon reaching idle, the starter is automatically turned off, and the engine is running. There is presently no FlightGear key binding for the fuel cutoff switch.
To shut off the engine, place the fuel cutoff control to TRUE.
If you shut down the engine in flight it will windmill. To airstart you will need at least 15% N2, just as with a ground start. When you have enough N2, place the cutoff control to FALSE and the engine will restart. Note that if you can't get enough N2 by speeding up, you can get it by using the starter.
The reverser still works, and is controlled in FlightGear with /controls/engines/engine[n]/reverser. With the reverser control on (TRUE), the engine will produce negative thrust in proportion to throttle position, i.e. to get more reverse
thrust, increase throttle.
Here's a new FGSimTurbine module. Changes are:
1. Adds starting and stopping functionality
2. Calculate() now calls other functions, based on the engine's state, which gives more readable code.
Until now turbine engines were always running as long as fuel was available. With this new module the engine defaults to OFF. To start with the engine running, the variable FGEngine::Running must be set to true at sim startup. In FlightGear this is done with --prop:/engines/engine[n]/running=true.
To start the engine (on the ground), first set the starter to ON, i.e. FGEngine::Starter is set to true. In FlightGear this is done by toggling /controls/engines/engine[n]/starter to TRUE. Note that the current FlightGear key binding will not work, as it causes the starter to quit when the key is released. A new key binding is needed, without the mod-up.
When N2 reaches 15% or greater, place the fuel cutoff control to FALSE. This is FGEngine::Cutoff. In FlightGear this is done with /controls/engines/engine[n]/cutoff set to FALSE. The engine will then accelerate to idle. Upon reaching idle, the starter is automatically turned off, and the engine is running. There is presently no FlightGear key binding for the fuel cutoff switch.
To shut off the engine, place the fuel cutoff control to TRUE.
If you shut down the engine in flight it will windmill. To airstart you will need at least 15% N2, just as with a ground start. When you have enough N2, place the cutoff control to FALSE and the engine will restart. Note that if you can't get enough N2 by speeding up, you can get it by using the starter.
The reverser still works, and is controlled in FlightGear with /controls/engines/engine[n]/reverser. With the reverser control on (TRUE), the engine will produce negative thrust in proportion to throttle position, i.e. to get more reverse thrust, increase throttle.
now read the config file out of the individual aircraft directory rather
than the collective Aircraft-yasim/ directory (which is now obsolete.)
This requires a corresponding update of the base package cvs.
The Propeller class ignored negative RPM but still returned a torque
value, which ratcheted up a higher and higher negative RPM until drag
overwhelmed the aircraft.
In reality, the propeller should windmill at a reasonable postive RPM,
introducing a constant drag on the aircraft -- the propeller should
*not* stop unless the plane is flying very slowly. That's a future
project.
I have added a fledgling replay system that records flight data and control
positions during the flight.
I have added an internal command called "replay" which will trigger a replay
of the entire saved flight data set. This could be bound to a keyboard or
menu command, in fact this entire module is screaming for someone to build
a gui to control playback speed, amount of playback, etc.
This is the initial version so there are kinks that still need to be worked
out, please be patient.
Square the normalized direction acceleration for the y and z axes, so
that turbulence predominantly affects pitch.
Bind to the /environment/turbulence/magnitude-norm and
/environment/turbulence/rate-hz properties in FlightGear.
This version handles a zero fuel load better. I found that if you try to consume fuel from an empty tank, with zero fuel flow, the FGEngine::Starved flag alternates
> > Here's a patch to add manual-pitch control to the propeller in YASim. A new
> > control axis "PROPPITCH" is added. Requires "manual-pitch" boolean property
> > in the "propeller" tag.
> >
> > Tags and Properties to add in order to enable:
> >
> > manual-pitch="true"
> >
> > <control-input axis="/controls/engines/engine[0]/propeller-pitch"
> > control="PROPPITCH" src0="0" src1="1" dst0="0.40" dst1="0.80"/>
> >
> > Note that for the time being, excessively low RPM or excessively high RPM is
> > brought undercontrol by a scaling range defined in the control-input tag
> > (see "dst0" and "dst1" properties).
I have attached some revisions for the UIUCModel and some LaRCsim.
The only thing you should need to check is LaRCsim.cxx. The file
I attached is a revised version of 1.5 and the latest is 1.7. Also,
uiuc_getwind.c and uiuc_getwind.h are no longer in the LaRCsim
directory. They have been moved over to UIUCModel.
I split the FGModelPlacement code out into it's own set of source files.
I created two versions of the fgLoad3DModel() routine. One that is
unecumbered by a panelnode dependency and one that is. acmodel.cxx is
the only place that needs to load an aircraft with instrument panels.
model.[ch]xx are now pretty much free to move over into simgear.
loader.[ch]xx should be able to follow closely behind.
This will be a big step towards being able to move the material management
code over into simgear.
scene management code and organizing it within simgear. My strategy is
to identify the code I want to move, and break it's direct flightgear
dependencies. Then it will be free to move over into the simgear package.
- Moved some property specific code into simgear/props/
- Split out the condition code from fgfs/src/Main/fg_props and put it
in it's own source file in simgear/props/
- Created a scene subdirectory for scenery, model, and material property
related code.
- Moved location.[ch]xx into simgear/scene/model/
- The location and condition code had dependencies on flightgear's global
state (all the globals-> stuff, the flightgear property tree, etc.) SimGear
code can't depend on it so that data has to be passed as parameters to the
functions/methods/constructors.
- This need to pass data as function parameters had a dramatic cascading
effect throughout the FlightGear code.
that after a reset or reposition, several FDM variable were not unbound
correctly and left dangling pointing to unallocated memory. This wasn't
a crash type bug, but those properties then had bogus values. This
specifically prevented the turn coordinator gyro modeling from working after
a reset or reposition.
ttStandard is copied from ttBerndt, with the following modifications:
1. All turbulence is diminished within three wingspans of the ground.
2. The horizontal forces are used to calculate the moments, but then
zeroed out so that only the vertical force is actually applied to
the aircraft.
3. The yaw moment is not used.
In fact, the horizontal forces and the yaw moment should be allowed,
but they are extremely rare compared to the vertical force and the
pitch/roll moments. For now, simply zeroing them gives the most
accurate feel.
FGExternalPipe is destructed.) This leaves the name pipe hanging around
even after flightgear exits, but assuming we put the files in /tmp that
shouldn't be a big deal.
ExternalNet interface:
- allows a much more closely coupled execution. A remote network FDM will run
at it's own rate, and maybe a particular data packets will come, maybe it
won't. This makes it very hard to control timing and keep the animation
smooth. There are also cpu scheduling issues with running multiple
processes on a single machine. The linux scheduler by default runs at
100hz. If an FDM process uses a sleep/alarm system to avoid wasting
CPU, it will be forced to run at 100hz, 50hz, 25hz, 20hz, etc. This
makes it *impossible* to serve a display system running at 60hz without
dropping frames.
- the downside is that the FDM process must now run on the same machine as
the master flightgear process.
- NED and UVW are working correctly
- knots is giving true airspeed instead of calibrated airspeed
- mach is not working at all
This desperately needs a trimming routine.
Some more cmall changes to the SimGear header files and removed the
SG_HAVE_NATIVE_SGI_COMPILERS dependancies from FlightGear.
I've added a seperate JSBSim patch for the JSBSim source tree.
really useful unless we simultaneously change the per-iteration deltas
to be smaller. Add another pseudo-tunable to control the speed with
which we change values across iterations. As it turns out, this is
much more effective than the threshold tunable. It does come at the
cost of lower solution performance, however.
Link the standalone executable against the source files explicitly rather
than libYASim, as the Irix linker can't handle the unneeded dependance on
other parts of FlightGear.
isn't well-constrained by the solution process is the drag-vs-aoa curve.
The default value that YASim picked was very steep, and resulted in most
of the jets flying their approaches *way* behind the power curve. This
changes the default to be more forgiving, and adds an "idrag" tunable
to the configuration file for tweakers.
Also, change the default gear springiness to be less stiff.
Changed steering to use the rudder command rather than the rudder
position. During taxi, the rudder trim shouldn't affect the steering
in any serious way.
This should be configurable in the aircraft file, since not all
aircraft use the rudder pedals for ground steering.
[In FlightGear, this may make it easier to taxi straight.]
The general idea is to help clean up some aspects of the FDM init and be
able to provide startup conditions in a less ambiguous manner.
Previously, things like positions, orientations, and velocites were set on
"the bus". These had to be read by the FDMs which then were supposed to
initialized themselves to those values and turn write around and start
modifying those values. It was messy and cumbersome.
Now, all the initial fdm conditions are written to a sub-[property-]tree
under /sim/presets/
The values in /sim/presets/ always stay set to what the user has specified.
The user can change these at his/her liesure, and then request a "reset"
which will reset to the new conditions. I don't even want to say how this
worked before. :-)
Now, an script, or gui interface can stage a set of initial conditions while
the sim is running (without disrupting it), and then call "reset" to commit
the change.
People who should worry about all this are FDM writters, and a small few
others who care about over all program structure and flow.
