"minor update for the rotor FDM. It results in a more realistic
calculation of the phase shift of rotor and therefor in a little bit
more realistic flight behavior.
(Additionally you can modify the initial position of the rotor and some
(not finished) modifications for the jet ranger rotor)."
"""
- ground properties (e.g. feel bumpiness and the reduced friction of
grass or go swimming with the beaver)
- initial load for yasim gears (to get rid of the jitter the beaver has
on ground)
- glider/winch/aerotow (do winch start with YASim glider or do aerotow
over the net) I will place a how-to on the wiki soon, here very short:
use the sgs233y (or the bocian if you have AJ (up ot now) non-GPL
bocian)
winch start: Ctrl-w for placing the winch, hold w to winch, press
Shift-w to release the tow
aerotow: Place the glider within 60m to a MP-aircraft, press
Ctrl-t to tow to this aircraft. If the MP-aircraft is the
J3 and the patch is installed on both sides, the J3 feels the
forces, too. The J3-pilot has to taxi very slow up to the
moment, the glider starts moving. Increase the throttle gently.
Don't lift the J3 early, wait for the glider being lifted,
lift gently.
"""
utils/Modeller/Makefile.am src/FDM/YASim/Makefile.am:
Remove -lssg from the linker lines.
Do no longer build threedconvert. A very similar functionality
is available with osgvconv. But leave threedconvert in place
if somebody will need that ...
I found a small conspicuity in YASim. The destructor of the fdm was
never called, therefore a modification of the heli fdm (not in cvs) did
not work after reset (I tie some properties and untie them in the
destructor, but the destructor was not called and the tieing failed
after reset. I don't know if any other parts of YASim need their
destructors, at least it wastes memory.
Another small fix I have made to the turbulence.cpp. The code needed,
that (a-floor(a)) is >=0 and <1. This is analytical correct, but
numerical only for "small" values. In normal fg-operation a in this
function is always small, but with unrealistic parameters in the
aircraft config file it is not and then fg crashes (instead a crash of
the aircraft or cataputling it far away).
More realistic calculation of vortices at the blades and therefore
real airfoil parameters can be used now (not to be mixed up with the
vortex ring state which is still not simulated), ground effect is now
continuous e. g. at buildings, calculating of the rotor in more than 4
directions, better documentation of the airfoil parameters.
values that were angles between the aircraft's orientation and the
global velocity vector, not the airflow velocity. So the HUD velocity
vector was wrong when the wind was non-zero. Fix that.
generates a data file of aerodynamic lift and drag (and L/D) against
AoA at a specified speed and altitude through a full circle. Wrote it
to track down the YF-23 superthrust issue, but it wasn't any help.
All the forces look fine.
state. The only really obvious problem was a giant negative engine
RPM, which happened because of a lack of clamping in the engine code
combined with the YF-23's ability to actually reach speeds near the
engines _vMax value. It's not clear to me that this will fix the
superthrust issue at high AoA's, but it's an obvious bug nonetheless.
+ The wing compilation step was accidentally omitting regions that lie
between the tips and the first/last control object. That's a real
problem for wings that contain no controls, and a significant issue
for those that contain only a few. I'm stunned that this went
undetected for so long.
+ The Surface::flapLift() function was oddly returning 1.0 Newtons as
a minimum, instead of zero.
bunch of memory leaks that had accumulated over the years. FlightGear
doesn't currently bother to destroy and recreate a YASim context, but
at least it can do so now without worry.
groundcache addition -- the ground callback doesn't do anything at
solution time, so the ground plane was unset. Valgrind was whining
about this; it's not clear that it was actually causing a problem.
and in the calculation of the launchbar angle (by Vivian).
It also calculates the holdback angle, and sets a Boolean value which
can be used to initiate the release of the catapult strop submodel at
the appropriate moment (new code by Vivian).
control to piston engines that allows external scripts to control the
turbo/supercharger boost programatically by setting this axis to
values in the range [0:1]. It also adds a "turbo-lag" attribute (a
time in seconds) to engines implementing turbocharger spooling delays.
This isn't terribly well tested, but doesn't seem to have broken
anything.
propeller pitch stops for constant speed propellers. The default
values are the same as the previous hard-coded values. The new
attributes, "fine-stop" and "coarse-stop", are documented in the base
package, Docs/README.yasim.
This patch makes use of the vectors now available in simgear with that past
patch. And using that it simplyfies the carrier code somehow.
- Small additional factory's to the quaternion code are done in the simgear
part. Also more explicit unit names in the factory functions.
- The flightgear part makes use of them and simplyfies some computations
especially in the carrier code.
- The data part fixes the coordinate frames I used for the park positions in
the carrier to match the usual ones. I believed that I had done so, but it
was definitly different. Also there are more parking positions avaliable now.
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).
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.
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 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.
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.
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.
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 ...
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. :)
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.
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.
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.
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.
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.
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.
> > 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).
