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Documented twist and incidence properties for wings.

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david 2003-02-18 20:11:52 +00:00
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115
Aircraft-yasim/README.yasim
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@ -7,23 +7,23 @@ different from the coordinate system used by JSBSim. Sorry. The
origin can be placed anywhere, so long as you are consistent. I use
the nose of the aircraft.
XML Tags
--------
XML Elements
------------
airplane: The top-level tag for the file. It contains only one
airplane: The top-level element for the file. It contains only one
attribute:
mass: The empty (no fuel) weight, in pounds.
approach: The approach parameters for the aircraft. The solver will
generate an aircraft that matches these settings. The tag
can (and should) contain <control> tags indicating pilot
generate an aircraft that matches these settings. The element
can (and should) contain <control> elements indicating pilot
input settings, such as flaps and throttle, for the
approach.
speed: The approach airspeed, in knots TAS.
aoa: The approach angle of attack, in degrees
cruise: The cruise speed and altitude for the solver to match. As
above, this should contain <control> tags indicating
above, this should contain <control> elements indicating
aircraft configuration. Especially, make sure the engines
are generating enough thrust at cruise!
speed: The cruise speed, in knots TAS.
@ -41,37 +41,47 @@ fuselage: This defines a tubelike structure. It will be given an even
wing: This defines the main wing of the aircraft. You can have
only one (but see below about using vstab objects for extra
lifting surfaces). The wing should have a <stall> subtag to
indicate stall behavior, control surface subtags (flap0,
lifting surfaces). The wing should have a <stall> subelement to
indicate stall behavior, control surface subelements (flap0,
flap1, spoiler, slat) to indicate what and where the control
surfaces are, and <control> subtags to map user input
surfaces are, and <control> subelements to map user input
properties to the control surfaces.
x,y,z: The "base" of the wing, specified as the location of
the mid-chord (not leading edge, trailing edge, or
aerodynamic center) point at the root of the LEFT
(!) wing.
length: The length from the base of the wing to the midchord
point at the tip. Note that this is not the same
thing as span.
chord: The chord of the wing at its base, along the X axis
(not normal to the leading edge, as it is
sometimes defined).
taper: The taper fraction, expressed as the tip chord
divided by the root chord. A taper of one is a
hershey bar wing, and zero would be a wing ending
at a point. Defaults to one.
sweep: The sweep angle of the wing, in degrees. Zero is
no sweep, positive angles are swept back.
Defaults to zero.
dihedral: The dihedral angle of the wing. Positive angles
are upward dihedral. Defaults to zero.
idrag: Multiplier for the "induced drag" generated by this
surface. In general, low aspect wings will
generate less induced drag per-AoA than high
aspect (glider) wings. This value isn't
constrained well by the solution process, and may
require tuning to get throttle settings correct in
high AoA (approach) situations.
x,y,z: The "base" of the wing, specified as the location of
the mid-chord (not leading edge, trailing edge, or
aerodynamic center) point at the root of the LEFT
(!) wing.
length: The length from the base of the wing to the midchord
point at the tip. Note that this is not the same
thing as span.
chord: The chord of the wing at its base, along the X axis
(not normal to the leading edge, as it is
sometimes defined).
incidence: The incidence angle at the wing root, in degrees.
Zero is level with the fuselage (as in an
aerobatic plane), positive means that the leading
edge is higher than the trailing edge (as in a
trainer).
twist: The difference between the incidence angle at the
wing root and the incidence angle at the wing
tip. Typically, this is a negative number so
that the wing tips have a lower angle of attack
and stall after the wing root (washout).
taper: The taper fraction, expressed as the tip chord
divided by the root chord. A taper of one is a
hershey bar wing, and zero would be a wing ending
at a point. Defaults to one.
sweep: The sweep angle of the wing, in degrees. Zero is
no sweep, positive angles are swept back.
Defaults to zero.
dihedral: The dihedral angle of the wing. Positive angles
are upward dihedral. Defaults to zero.
idrag: Multiplier for the "induced drag" generated by this
surface. In general, low aspect wings will
generate less induced drag per-AoA than high
aspect (glider) wings. This value isn't
constrained well by the solution process, and may
require tuning to get throttle settings correct in
high AoA (approach) situations.
hstab: These defines the horizontal stabilizer of the aircraft.
Internally, it is just awing objects and therefore work the
@ -91,11 +101,16 @@ vstab: A "vertical" stabilizer. Like hstab, this is just another
with the solver computation, so you can have none, or as
many as you like.
stall: A subtag of a wing (or hstab/vstab) that specifies the stall
behavior.
aoa: The stall angle (maximum lift) in degrees.
stall: A subelement of a wing (or hstab/vstab) that specifies the
stall behavior.
aoa: The stall angle (maximum lift) in degrees. Note that
this is relative to the wing, not the fuselage (since
the wing may have a non-zero incidence angle).
width: The "width" of the stall, in degrees. A high value
indicates a gentle stall. Low values are viscious.
indicates a gentle stall. Low values are viscious
for a non-twisted wing, but are acceptable for a
twisted one (since the whole wing will not stall at
the same time).
peak: The height of the lift peak, relative to the
post-stall secondary lift peak at 45 degrees.
Defaults to 1.5. This one is deep voodoo, and
@ -103,7 +118,7 @@ stall: A subtag of a wing (or hstab/vstab) that specifies the stall
explanation if you're curious.
flap0, flap1, slat, spoiler:
These are subtags of wing/hstab/vstab objects, and specify
These are subelements of wing/hstab/vstab objects, and specify
the location and effectiveness of the control surfaces.
start: The positition along the wing where the control
surface begins. Zero is the root, one is the tip.
@ -127,8 +142,8 @@ flap0, flap1, slat, spoiler:
slat extension.
jet: A turbojet/fan engine. Really cheezy right now, so there's
not much to set. It accepts a <control> subtag to map a
property to its throttle setting, and an <actionpt> subtag
not much to set. It accepts a <control> subelement to map a
property to its throttle setting, and an <actionpt> subelement
to place the action point of the thrust at a different
position than the mass of the engine.
x,y,z: The location of the engine, as a point mass. If no
@ -138,13 +153,13 @@ jet: A turbojet/fan engine. Really cheezy right now, so there's
thrust: The maximum sea-level thrust, in pounds.
propeller: A propeller connected to a non-turbocharged piston engine
The engine model is evolving, this tag is likely to change
The engine model is evolving, this element is likely to change
radically in the future.
x,y,z: The position of the mass (!) of the
engine/propeller combination. If the point
of force application is different (and it
will be) it should be set with an <actionpt>
subtag.
subelement.
mass: The mass of the engine/propeller, in pounds.
moment: The moment, in kg-meters. This has to be
hand calculated and guessed at for now. A
@ -159,11 +174,11 @@ propeller: A propeller connected to a non-turbocharged piston engine
takeoff-rpm: ...at the given takeoff RPM.
actionpt: Defines an "action point" for an enclosing jet or propeller
tag. This is the location where the force from the thruster
element. This is the location where the force from the thruster
will be applied.
x,y,z: The location of force application.
gear: Defines a landing gear. Accepts <control> subtags to map
gear: Defines a landing gear. Accepts <control> subelements to map
properties to steering and braking.
x,y,z: The location of the fully-extended gear tip.
compression: The distance along the Z axis that the gear
@ -235,7 +250,7 @@ weight: This is an added weight, something not part of the empty
which results in no aerodynamic force (internal
cargo).
control: This tag, which can appear in two different contexts,
control: This element, which can appear in two different contexts,
manages a mapping from fgfs properties (user input) to
settable values on the aircraft's objects. Note that the
value to be set MUST (!) be valid on the given object type.
@ -275,8 +290,8 @@ control: This tag, which can appear in two different contexts,
applicable to values that have a range of [-1:1] or
[0:1].
A control tag can also appear inside of an <approach> or
<cruise> tag. Here, it specifies a particular value of an
A control element can also appear inside of an <approach> or
<cruise> element. Here, it specifies a particular value of an
axis mapping that should be true under the given
conditions. At cruise, the throttle is generally at a high
setting, the flaps and slats are up During approach
@ -284,4 +299,4 @@ control: This tag, which can appear in two different contexts,
axis: As above, the name of the input property.
value: A floating point number that the property is expected
to hold.
to hold.