sitting on the runway, my plane turns or slides in the wind
- This is a known problem with how ground
friction is handled, made much worse by computational flutter. See the
detailed description on the Theory
page. Current X-Plane versions only suffer from this problem at
extremely low frame rates or in very high winds. If your plane is
uncontrollable on the ground under "reasonable" conditions...
- A problem has been reported with older aircraft loading up with a
tire friction coefficient of zero. You need to set the Cf to a
reasonable value (like 0.75 for maximum friction and 0.025 for rolling
resistence) in PlaneMaker. See the aircraft
format and conversion page for details.
How do I steer the plane on the ground?
It depends on the plane and what kind
of control setup you have. Most X-Plane aircraft are set up with
nosewheel steering even if the real plane being modeled doesn't have
it. Real planes without steerable wheels are typically steered with
differential braking on the main gear, but not all of us have the fancy
(and expensive) pedals that support this. BTW, the term "nosewheel
steering" is a generic term that applies to tail draggers as well, only
in their case it's the tail wheel that steers.
Anyway... If you have a rudder axis assigned - i.e., if you have rudder
pedals or a twist grip on your stick or whatever and you've set it up
as the Yaw axis in the joystick setup, the rudder axis controls
nosewheel steering. If you don't, your stick aileron control (i.e.,
left-right stick) controls the nosewheel steering. (Only the nosewheel
steering - there's no implicit aileron to rudder coupling.)
When I apply full steering on
the ground the brakes come on
This is a feature to help you get
around a tight turn. What's happening is X-Plane is applying
differential braking - braking force to the wheel on the inside of the
turn - when you apply full, or nearly full, steering input. You'd do
this with a real plane. X-Plane also applies differential braking in
response to any steering input if the nose or tail wheel is
free-castering. Assigning control axes to the left and right brakes
(e.g., if you have the CH Pro Pedals with toe brakes) overrides this
Ground handling is lousy - I get
squealing tires when I try to turn
First off, this is an airplane, not a
sports car! Don't expect the same handling with those little tires as
you'd get with the Pirelli 245ZR17/45s you have on your car! Also
remember that planes with tricycle gear have lots of angular momentum
and relatively little weight on the nose wheel.
The other problem is that with no force feedback, it's easy to
overcontrol. Many planes allow extreme nosewheel angles for tight
turns, so you really have to ease into the turn slowly and gently.
just bought X-Plane and I'm having a hard time just controlling the
I can't get the plane into level flight
or even get controllable responses to the stick.
A couple of recommendations:
- Get yourself upgraded to the current version if you haven't
already done so. There are many bug fixes and improvements over
whatever version is on the DVD.
- Every time you start up X-Plane, move the stick through its
entire operating range. X-Plane saves the stick setup when you exit,
but it still auto-calibrates when it sees the extremes of the stick
- In the Center tab of the stick setup (called Null Zone in earlier
versions), give yourself a null zone of about .05, make sure you have
the stick center set up right, and pull out the center response
sliders a ways so you get a modest bend in the response curve. This
reduces stick sensitivity on center and makes it easier to handle.
(These settings are new features in 8.15, BTW. You won't see them in
older versions.) The main problem is that the feel of any PC joystick
is completely different from what you get on a real plane, and you just
have to get used to it. It's very easy to overcontrol, and these
adjustments help prevent that. Most of flying a real plane is done with
pretty small control inputs and X-Plane responds accordingly. The
problem is you don't have the opposing forces you'd feel in a real
- Start with a plane that's relatively easy to fly. My favorite is
the Beech King Air. It's a nice stable plane that's not over-sensitive,
and being a twin it doesn't have the prop torque problems of a single
engine plane. Once you get used to the feel of the stick you can move
on to some of the trickier planes. The X-Plane C-172, BTW, is generally
regarded as having some pretty serious accuracy problems, especially in
the area of ground handling. There are a number of much better C-172
models available on X-Plane.org. The included Piper Malibu is a lot
- Trim the plane as soon as you're off the ground. Keep trimming it
as you build up airspeed and climb out. Keep trimming it until you're
in stable, level flight. Then keep trimming it anyway. The problem is
that real planes, once they're set up properly, are basically in
correct trim for level flight. The planes in X-Plane, on the other
hand, start out basically out of trim and you have to get them set up
right every time you take off. You'll find yourself having to tweak the
trim a lot more often than in a real plane. This has been the subject
of a lot of debate. I suspect it has to do with secondary aero effects
that are not completely modeled by X-Plane.
I put elevator and aileron trim on the stick's hat switch so that it
works like the electric trim in a real plane. After several minutes
flight I can usually get the King Air trimmed out well enough that it
will fly hands off for a minute or two. Even so, it requires the
occasional nudge to stay level because you simply can't get the very
fine adjustment in a sim that you can get in real life.
My plane doesn't want to
It keep trying to roll to the left or right.
That's called prop torque. The engine torque gets reflected back into
the plane (another manifestation of Newton's third law of motion). You
need to compensate with aileron deflection. You'll have to readjust the
trim in response to any change in engine power, airspeed, or attitude.
As I change airspeed with full power, the
plane starts to roll the wrong way.
Ordinarily, the roll tendency you feel at takeoff (left
a clockwise prop, right for a counterclockwise prop) should decrease
smoothly as you pick up speed and your ailerons become more effective.
If there are abrupt changes in the roll tendency or the plane needs
opposite aileron trim at certain speeds, it may be suffering from
inaccuracies in the modelling of spiral propwash. Increasing the number
of wing elements helps to solve this problem.
My (single engine prop)
veers to one side during the takeoff roll
This effect results from either P-factor or spiral
propwash, or both. See the following...
Real pilots tell me you need to use rudder
trim to keep a single engine plane straight.
There are two effects, P-factor
and spiral propwash, that induce a yaw force on the plane during low
speed, high power flight. X-Plane prior to version 6.14 does not
correctly model either of these effects. Versions 6.21 and later model
both. (I am not completely sure when a bug in the modelling of P-factor
was fixed, but it is correct in 6.51 and after.) The modelling of
propwash works correctly for some planes and not for others - it
on the wing and stabilizer configuration. This is still under
does my plane keep bouncing around?
That's atmospheric turbulence.
But I checked the weather menu
and wind and turbulence are at zero.
They may not be. The slider controls in
the weather menu are a bit deceptive. The default weather setup (when
you start X-Plane with clean preferences) has a pretty significant
amount of turbulence set up, even through the summary Wind and
Turbulence slide in the lower left may indicate zero. To really set
and turbulence to zero, move the summary slider off zero (watch the
and turbulence sliders in the center column wiggle around) and then
it back to zero.
Why can't I fly a loop in
Well, first off, you can. Pick the right plane (high power
to wing loading ratio) and fly it right (start with enough speed and
manage your energy properly) and you can fly a pretty decent loop. Lots
of people have done it. That said, it may be harder in X-Plane than in
some other sims because other sims may not properly model prop torque
the higher drag that results from a high angle of attack. If you're
losing control near the top of the loop it's probably because you've
out of airspeed, not because there's a problem with X-Plane.
As of version 6.14, X-Plane uses full quaternion math for its flight
model. Users report that loops and other forms of vertical flight are
now correctly handled.
A new airfoil model as of version 6.50 improves the behavior beyond the
stall angle, improving the accuracy of spins and stalls.
But... In versions prior to 6.14 there are problems. From the X-Plane
"Rolls and stalls are possible, although loops and spins
are not entirely accurate due to the limitations of Eulerian flight
propagation and turbulence simulation, respectively. (Eulerian flight
propagation, which X-plane uses, has a hard time tracking the heading
when you are pointed straight up, and the turbulent airflow of a
wing is still not completely mathematically simulateable by any
The X-Plane flight model pre- version 6.14 does not behave correctly
when the plane is very nearly vertical. You can see problems ranging
from mild anomalous roll and yaw all the way to loss of control and
getting trapped in a vertical attitude.
I'm flying along and all
of a sudden the flight model goes crazy.
Any of the following symptoms:
You've encountered computational flutter. The aircraft's parameters are
changing too fast for the flight model's frame rate to handle
To avoid the problem, slow down or reduce rendering options to increase
your frame rate. See the Theory section
for a complete explanation of computational
- Sudden uncommanded, uncontrollable roll or yaw
- Sudden unexplained acceleration
- Uncontrollable bouncing on the ground
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