Change the drag coefficient for fuselages along the Y and Z axes
(i.e. perpendicular to the fuselage's main axis) to use a fixed
value of 0.5. (The value can still be adjusted using the fuselage's
"cy" and "cz" XML attributes.)
For the Y-axis and Z-axis drag on fuselages, YASim originally used
a drag coefficient equal to:
(solver drag factor) * (fuselage length/width ratio)
This value turns out to be way too small for well-streamlined
aircraft, even those with long, narrow fuselages, and especially
so for those with short, stubby fuselages. Such fuselages are
streamlined in the X direction, but not along Y or Z.
0.5 is only a ballpark estimate, but it's reasonably close for the
common case of a fairly long fuselage with a round cross section. For
flat-sided fuselages, a larger value should be used, up to a maximum
of 2 for a slab-sided block. For short fuselages, the value should be
reduced to account for end effects. The fuselage's "cy" and "cz" XML
attributes can be modified to make such adjustments.
This fix won't affect straight flight much, but it should have a strong
impact on some maneuvers. For example, it will make slips more
effective and may make knife-edge flight easier on aerobatic aircraft
which should be capable of it.
Only aircraft which specify version="YASIM_VERSION_32" or newer are
affected.
This commit is in prepartion for the following commit, which is a bug fix for
Issue 1463 (YASim underestimates off-axis forces on fuselages).
Previously the solver would adjust the drag factor for all of an Airplane's
non-Wing Surfaces in one pass, with no attempt to distinguish Fuselage Surfaces
from the Surfaces for Gear and Weights. This makes it difficult to modify how
fuselage drag is calculated while leaving unaffected the drag for landing gear
and external weights.
Now the solver adjusts the drag for an Airplane's fuselages, landing gear, and
external weights in three separate passes. To do this, each Fuselage now has a
list of its Surfaces. The fuselage pass simply iterates through the list of
Fuselages, running through each Fuselage's list of Surfaces.
The Airplane's list of non-Wing Surfaces, "_surfs", is no longer used here, but
there may still be uses of it elsewhere.
Correct handling of fuselage's "midpoint" XML attribute so that the midpoint's
location matches the point assumed by all aircraft developers and YASim docs.
This means the fuselage won't be generated "back-to-front".
Also correct the variation of diameter for tapered fuselages so that both ends
of the fuselage narrow from the midpoint to the endpoints.
Before this, one end was narrowing from the endpoint to the midpoint, the
opposite of what was expected.
These changes affect both weight distribution and the distribution of lateral
aerodynamic forces.
user attribute "version" of the airplane element of the YASim config file
to define the version this config uses.
Example:
<airplane mass="1344" version="YASIM_VERSION_CURRENT">
Initially, the following can be used:
YASIM_VERSION_ORIGINAL - The original version of YASim as implemented up to
FlightGear 3.0.0
YASIM_VERSION_32 - The version of YASim implemented in FlightGear 3.2.x
(and the development version 3.1.x)
YASIM_VERSION_CURRENT - The current and latest version of YASim.
add checks against buffer overruns
CVE-2012-2091 mentions various buffer overruns in simgear and
flightgear. This patch addresses this issue in Rotor::getValueforFGSet().
From: Tom Callaway
are the accelerations (forces) as felt from the pilot's perspective. This
combines the accelerations due to change in velocity vector and gravity.
Previosly the gravity part was right, but the body accelerations were being
transformed incorrectly. The error was very subtle and basically amounted to
the fact that inverting an axis of a vector before transforming it is not
equivalent to transforming the vector and then inverting that axis.
After this fix, pilot accelerations + gyro + gps can be fed into an external
kalman filter and it will converge properly (extra confirmation that there
was a problem and this fix corrects it.)
Replace SG_GENERAL by more specific log classes in many places.
Allow "," to separate logging classes (using "|" is odd on the
command-line).
Also add new option to make logging more useful for developers.
You can use:
--log-level=debug --log-class=environment
to only get environment debug messages, or
--log-level=debug --log-class=sound,ai
to only get debug messages related to the sound or AI subsystem.
