PIO in yaw axis

Archived from groups: alt.games.microsoft.flight-sim (More info?)

I previously had the Win95 ver of MSFS (ver 6.0) and was disappointed
in its performance. Ten years later I just installed the 2004 ver
operating on a new fast computer running XP. The performance is still
bad. I would have thought that after 10 years MS would have much
improved the performance. As a pilot and servo engineer, I feel
qualified to comment on one of its major shortcomings, namely
instability in the yaw axis which causes PIO. The roll and pitch axes
seem to perform reasonably, but not the yaw axis. This
problem is most noticeable on the ground or pproaching the runway.
It's not as noticeable in the air as there are no nearby objects to use
as a reference. No real planes behave this way. If they did, they
would all have crashed on takeoff. I have played with the
sensitivities and null factors as well as P factor torque and scenery
settings. Nothing really helps. It seams that one problem is that the
flight model does not take into account the mass of the airplane so
that there is no rotational inertia in the yaw axis. Also there is a
delay between control input and effect which is not due to the
computer's processor speed. This all adds up to the PIO in the yaw
axis. I just hope that any wantabe pilots don't get discouraged and
never take real flight lessons due to their experience with MSFS.
Flying a real plane is much, much easier.

Does anyone qualified to speak to this matter know what's wrong with
MS's flight model? Is there any way to correct this shortcoming?

Pilot John

_________________________________________________________
Posted via the -Web to Usenet- forums at http://forums.simradar.com
Visit www.simradar.com and try our Flight Simulation Search Engine!
17 answers Last reply
More about axis
  1. Archived from groups: alt.games.microsoft.flight-sim (More info?)

    There is a P-factor slider in the realism bar. I have every slider to
    the right (max realism, supposedly) and even with no wind and joystick
    centered (verified by the Sidewinder utility) I still yaw left. So to
    sum up, those who have never experienced the P-factor probably don't
    have the slider on max.

    Arthur wrote:
    > Would someone please elaborate on what PIO is? I have a general idea but am
    > still not sure......I'm just a simmer, ya know : )
    >
    > Arthur
    >
    > "Dudley Henriques" <dhenriques@noware .net> wrote in message
    > news:L0bGe.18542$aY6.13171@newsread1.news.atl.earthlink.net...
    > >
    > > "PilotJohn" <PilotJohn@forums.simradar.com> wrote in message
    > > news:1122576742.30535@forums.simradar.com...
    > >>I previously had the Win95 ver of MSFS (ver 6.0) and was disappointed
    > >> in its performance. Ten years later I just installed the 2004 ver
    > >> operating on a new fast computer running XP. The performance is still
    > >> bad. I would have thought that after 10 years MS would have much
    > >> improved the performance. As a pilot and servo engineer, I feel
    > >> qualified to comment on one of its major shortcomings, namely
    > >> instability in the yaw axis which causes PIO. The roll and pitch axes
    > >> seem to perform reasonably, but not the yaw axis. This
    > >> problem is most noticeable on the ground or pproaching the runway.
    > >> It's not as noticeable in the air as there are no nearby objects to use
    > >> as a reference. No real planes behave this way. If they did, they
    > >> would all have crashed on takeoff. I have played with the
    > >> sensitivities and null factors as well as P factor torque and scenery
    > >> settings. Nothing really helps. It seams that one problem is that the
    > >> flight model does not take into account the mass of the airplane so
    > >> that there is no rotational inertia in the yaw axis. Also there is a
    > >> delay between control input and effect which is not due to the
    > >> computer's processor speed. This all adds up to the PIO in the yaw
    > >> axis. I just hope that any wantabe pilots don't get discouraged and
    > >> never take real flight lessons due to their experience with MSFS.
    > >> Flying a real plane is much, much easier.
    > >>
    > >> Does anyone qualified to speak to this matter know what's wrong with
    > >> MS's flight model? Is there any way to correct this shortcoming?
    > >
    > > Well..I might be somewhat qualified on PIO having done some research
    > > testing in T38's on PIO along with inertia coupling and departures :-).
    > > Based on this and the constant testing I do with developers in the
    > > simulator, I have to tell you in all honesty that I have never noticed
    > > anything approaching a PIO symptom on my system and with my controllers in
    > > any axis.
    > > As a simple test data point, I think you have to conclude that if someone
    > > other than yourself isn't having the issues you are describing, the
    > > problem is most likely at your end somewhere and not latent in the
    > > simulator's programming.
    > > Dudley Henriques
    > >
  2. Archived from groups: alt.games.microsoft.flight-sim (More info?)

    Here here Pilot John,

    I know for a fact that flying IRL is generally easier. Of course that is
    only an opinion, but it is based on experience. Flying in to my old airport
    EL 6614' a 152 on a warm day was kind of scary...but a 182 was real nice.

    Mr. Steve

    "PilotJohn" <PilotJohn@forums.simradar.com> wrote in message
    news:1122576742.30535@forums.simradar.com...
    >I previously had the Win95 ver of MSFS (ver 6.0) and was disappointed
    > in its performance. Ten years later I just installed the 2004 ver
    > operating on a new fast computer running XP. The performance is still
    > bad. I would have thought that after 10 years MS would have much
    > improved the performance. As a pilot and servo engineer, I feel
    > qualified to comment on one of its major shortcomings, namely
    > instability in the yaw axis which causes PIO. The roll and pitch axes
    > seem to perform reasonably, but not the yaw axis. This
    > problem is most noticeable on the ground or pproaching the runway.
    > It's not as noticeable in the air as there are no nearby objects to use
    > as a reference. No real planes behave this way. If they did, they
    > would all have crashed on takeoff. I have played with the
    > sensitivities and null factors as well as P factor torque and scenery
    > settings. Nothing really helps. It seams that one problem is that the
    > flight model does not take into account the mass of the airplane so
    > that there is no rotational inertia in the yaw axis. Also there is a
    > delay between control input and effect which is not due to the
    > computer's processor speed. This all adds up to the PIO in the yaw
    > axis. I just hope that any wantabe pilots don't get discouraged and
    > never take real flight lessons due to their experience with MSFS.
    > Flying a real plane is much, much easier.
    >
    > Does anyone qualified to speak to this matter know what's wrong with
    > MS's flight model? Is there any way to correct this shortcoming?
    >
    > Pilot John
    >
    > _________________________________________________________
    > Posted via the -Web to Usenet- forums at http://forums.simradar.com
    > Visit www.simradar.com and try our Flight Simulation Search Engine!
  3. Archived from groups: alt.games.microsoft.flight-sim (More info?)

    "PilotJohn" <PilotJohn@forums.simradar.com> wrote in message
    news:1122576742.30535@forums.simradar.com...
    >I previously had the Win95 ver of MSFS (ver 6.0) and was disappointed
    > in its performance. Ten years later I just installed the 2004 ver
    > operating on a new fast computer running XP. The performance is still
    > bad. I would have thought that after 10 years MS would have much
    > improved the performance. As a pilot and servo engineer, I feel
    > qualified to comment on one of its major shortcomings, namely
    > instability in the yaw axis which causes PIO. The roll and pitch axes
    > seem to perform reasonably, but not the yaw axis. This
    > problem is most noticeable on the ground or pproaching the runway.
    > It's not as noticeable in the air as there are no nearby objects to use
    > as a reference. No real planes behave this way. If they did, they
    > would all have crashed on takeoff. I have played with the
    > sensitivities and null factors as well as P factor torque and scenery
    > settings. Nothing really helps. It seams that one problem is that the
    > flight model does not take into account the mass of the airplane so
    > that there is no rotational inertia in the yaw axis. Also there is a
    > delay between control input and effect which is not due to the
    > computer's processor speed. This all adds up to the PIO in the yaw
    > axis. I just hope that any wantabe pilots don't get discouraged and
    > never take real flight lessons due to their experience with MSFS.
    > Flying a real plane is much, much easier.
    >
    > Does anyone qualified to speak to this matter know what's wrong with
    > MS's flight model? Is there any way to correct this shortcoming?

    Well..I might be somewhat qualified on PIO having done some research testing
    in T38's on PIO along with inertia coupling and departures :-).
    Based on this and the constant testing I do with developers in the
    simulator, I have to tell you in all honesty that I have never noticed
    anything approaching a PIO symptom on my system and with my controllers in
    any axis.
    As a simple test data point, I think you have to conclude that if someone
    other than yourself isn't having the issues you are describing, the problem
    is most likely at your end somewhere and not latent in the simulator's
    programming.
    Dudley Henriques
  4. Archived from groups: alt.games.microsoft.flight-sim (More info?)

    Would someone please elaborate on what PIO is? I have a general idea but am
    still not sure......I'm just a simmer, ya know : )

    Arthur

    "Dudley Henriques" <dhenriques@noware .net> wrote in message
    news:L0bGe.18542$aY6.13171@newsread1.news.atl.earthlink.net...
    >
    > "PilotJohn" <PilotJohn@forums.simradar.com> wrote in message
    > news:1122576742.30535@forums.simradar.com...
    >>I previously had the Win95 ver of MSFS (ver 6.0) and was disappointed
    >> in its performance. Ten years later I just installed the 2004 ver
    >> operating on a new fast computer running XP. The performance is still
    >> bad. I would have thought that after 10 years MS would have much
    >> improved the performance. As a pilot and servo engineer, I feel
    >> qualified to comment on one of its major shortcomings, namely
    >> instability in the yaw axis which causes PIO. The roll and pitch axes
    >> seem to perform reasonably, but not the yaw axis. This
    >> problem is most noticeable on the ground or pproaching the runway.
    >> It's not as noticeable in the air as there are no nearby objects to use
    >> as a reference. No real planes behave this way. If they did, they
    >> would all have crashed on takeoff. I have played with the
    >> sensitivities and null factors as well as P factor torque and scenery
    >> settings. Nothing really helps. It seams that one problem is that the
    >> flight model does not take into account the mass of the airplane so
    >> that there is no rotational inertia in the yaw axis. Also there is a
    >> delay between control input and effect which is not due to the
    >> computer's processor speed. This all adds up to the PIO in the yaw
    >> axis. I just hope that any wantabe pilots don't get discouraged and
    >> never take real flight lessons due to their experience with MSFS.
    >> Flying a real plane is much, much easier.
    >>
    >> Does anyone qualified to speak to this matter know what's wrong with
    >> MS's flight model? Is there any way to correct this shortcoming?
    >
    > Well..I might be somewhat qualified on PIO having done some research
    > testing in T38's on PIO along with inertia coupling and departures :-).
    > Based on this and the constant testing I do with developers in the
    > simulator, I have to tell you in all honesty that I have never noticed
    > anything approaching a PIO symptom on my system and with my controllers in
    > any axis.
    > As a simple test data point, I think you have to conclude that if someone
    > other than yourself isn't having the issues you are describing, the
    > problem is most likely at your end somewhere and not latent in the
    > simulator's programming.
    > Dudley Henriques
    >
  5. Archived from groups: alt.games.microsoft.flight-sim (More info?)

    I would love for the problem to be at my end and not inherent in MSFS.
    That would mean that there's some hope of fixing it if I can find out
    what's causing the problem. However, it's strange that I have the same
    identical problem on two different computers with two different
    joysticks (MS Sidewinder and Thrustmaster Pro) and no one else has the
    problem.

    _________________________________________________________
    Posted via the -Web to Usenet- forums at http://forums.simradar.com
    Visit www.simradar.com and try our Flight Simulation Search Engine!
  6. Archived from groups: alt.games.microsoft.flight-sim (More info?)

    PIO is Pilot Induced Oscillation. It is generally caused by
    overcontrolling out of phase with the needed correction. It can be
    made worse if there is a delay in the system so that the correction
    doesn't happen immediately when the control input is made.

    _________________________________________________________
    Posted via the -Web to Usenet- forums at http://forums.simradar.com
    Visit www.simradar.com and try our Flight Simulation Search Engine!
  7. Archived from groups: alt.games.microsoft.flight-sim (More info?)

    John,
    I run FS2004 on 2 computers. On one computer I use a CH F-16 Combat
    Stick, and CH Pro Pedals for rudder. On the other computer I have a Logitech
    Extreme 3D Pro "twist" stick thats used for pitch, roll, and twisting the
    stick for yaw. I find that all of my aircraft are much, much more
    controllable in the yaw axis when I am using the rudder pedals. Maybe its
    just that I am used to using rudder pedals to control yaw much more than I
    am used to using a "twist" joystick for rudder control. Maybe its because I
    don't have the sensitivity and null zone set right for the twist stick. Or
    maybe its because the pedals have a larger area of movement, which gives me
    finer control. But the yaw control that I have with the twist stick is so
    bad that I finally simply turned auto-rudder on, and stopped trying to
    fiddle with the twist joystick to control the rudder.
    My suggestion is to consider getting a good quality rudder pedal set. Be
    sure to get one that also supports differential toe braking also. I think
    you will find that it is much easier to control your aircraft using rudder
    pedals than using a twist joystick. Just something to consider....

    Randy L.

    "PilotJohn" <PilotJohn@forums.simradar.com> wrote in message
    news:1122576742.30535@forums.simradar.com...
    >
    > Does anyone qualified to speak to this matter know what's wrong with
    > MS's flight model? Is there any way to correct this shortcoming?
    >
    > Pilot John
    >
    > _________________________________________________________
    > Posted via the -Web to Usenet- forums at http://forums.simradar.com
    > Visit www.simradar.com and try our Flight Simulation Search Engine!
  8. Archived from groups: alt.games.microsoft.flight-sim (More info?)

    John, could you be more specific on the A/C involved (Stock or add-on etc.)
    and the type of joystick used? To be honest I NEVER noticed PIO on yaw axis
    during my whole MSFS career. PIO is as you know a combination of instability
    and excessive pilot's inputs. So my first thought is of a indecent joystick
    behaviour. A simple approach to that problem might be to use keyboard
    commands and check the respective behaviour.
    --
    Oskar Wagner
    (retired Captain)

    Remember, in the great scheme of things, we're all small potatoes....
    "PilotJohn" <PilotJohn@forums.simradar.com> schrieb im Newsbeitrag
    news:1122576742.30535@forums.simradar.com...
    >I previously had the Win95 ver of MSFS (ver 6.0) and was disappointed
    > in its performance. Ten years later I just installed the 2004 ver
    > operating on a new fast computer running XP. The performance is still
    > bad. I would have thought that after 10 years MS would have much
    > improved the performance. As a pilot and servo engineer, I feel
    > qualified to comment on one of its major shortcomings, namely
    > instability in the yaw axis which causes PIO. The roll and pitch axes
    > seem to perform reasonably, but not the yaw axis. This
    > problem is most noticeable on the ground or pproaching the runway.
    > It's not as noticeable in the air as there are no nearby objects to use
    > as a reference. No real planes behave this way. If they did, they
    > would all have crashed on takeoff. I have played with the
    > sensitivities and null factors as well as P factor torque and scenery
    > settings. Nothing really helps. It seams that one problem is that the
    > flight model does not take into account the mass of the airplane so
    > that there is no rotational inertia in the yaw axis. Also there is a
    > delay between control input and effect which is not due to the
    > computer's processor speed. This all adds up to the PIO in the yaw
    > axis. I just hope that any wantabe pilots don't get discouraged and
    > never take real flight lessons due to their experience with MSFS.
    > Flying a real plane is much, much easier.
    >
    > Does anyone qualified to speak to this matter know what's wrong with
    > MS's flight model? Is there any way to correct this shortcoming?
    >
    > Pilot John
    >
    > _________________________________________________________
    > Posted via the -Web to Usenet- forums at http://forums.simradar.com
    > Visit www.simradar.com and try our Flight Simulation Search Engine!
  9. Archived from groups: alt.games.microsoft.flight-sim (More info?)

    172 aircraft and MS Sidewinder (non-force feedback) and Thrustmaster
    Pro joy sticks. Both behave about the same in yaw re PIO. The
    keyboard works better because you can make smaller inputs than are
    possible with the joystick. The joystick input is too much, even
    with the sensitivity set at the bottom ot the range. However, the main
    problem leading to PIO is the delay between input and result. The
    problem is similar to trying to adjust the temperature of your shower
    when there is four feet of pipe between the knob and the nozzle.

    _________________________________________________________
    Posted via the -Web to Usenet- forums at http://forums.simradar.com
    Visit www.simradar.com and try our Flight Simulation Search Engine!
  10. Archived from groups: alt.games.microsoft.flight-sim (More info?)

    Hi Arthur;
    PIO is an acronym for "pilot induced oscillation". Basically, without all
    the aerodynamic explanation, it's what can happen if a pilot's corrective
    action to an excursion by the airplane in any of the airplane's axis' gets
    out of phase with the reaction caused by the control being used to initiate
    input on that axis.
    For example, the T38 Talon is an extremely high fuselage to wing ratio (high
    fuselage mass ratio) aircraft. As such, and because it utilizes irreversible
    hydraulic controls for pitch (stabilator), it's common in this airplane to
    correct a pitch excursion up or down with a stick input to the stab, then
    because the reaction to the input is so fast, a corrective input to the
    initial input is initiated to correct again. The result can be an out of
    phase condition that actually worsens the situation. In other words you're
    correcting up when you should be correcting down :-) This condition is so
    dangerous on final in the T38 that it's a know and listed issue in the dash
    1 for the airplane.
    The corrective action for a PIO condition in the T38 is to let go of the
    stick to stabilize the airplane then reapply necessary pressure for the
    flight condition.
    PIO usually occurs on axis after an initial correction input has been made.
    To put it simply, it's a correction to a correction that's out of phase with
    the actual correction required.
    PIO is usually found in high performance airplanes with extremely sensitive
    controls like the T38. You can also find it in manual controls such as found
    in a Pitts or an Extra. It's mostly found in pitch, but can be an issue in
    any sensitive axis. The solution to handling PIO is trained smoothness of
    control application.
    Hope this helps a bit.
    Dudley

    "Arthur" <alspectorz@rogers.com> wrote in message
    news:W9SdnVAeMYJsxnTfRVn-ug@rogers.com...
    > Would someone please elaborate on what PIO is? I have a general idea but
    > am still not sure......I'm just a simmer, ya know : )
    >
    > Arthur
    >
    > "Dudley Henriques" <dhenriques@noware .net> wrote in message
    > news:L0bGe.18542$aY6.13171@newsread1.news.atl.earthlink.net...
    >>
    >> "PilotJohn" <PilotJohn@forums.simradar.com> wrote in message
    >> news:1122576742.30535@forums.simradar.com...
    >>>I previously had the Win95 ver of MSFS (ver 6.0) and was disappointed
    >>> in its performance. Ten years later I just installed the 2004 ver
    >>> operating on a new fast computer running XP. The performance is still
    >>> bad. I would have thought that after 10 years MS would have much
    >>> improved the performance. As a pilot and servo engineer, I feel
    >>> qualified to comment on one of its major shortcomings, namely
    >>> instability in the yaw axis which causes PIO. The roll and pitch axes
    >>> seem to perform reasonably, but not the yaw axis. This
    >>> problem is most noticeable on the ground or pproaching the runway.
    >>> It's not as noticeable in the air as there are no nearby objects to use
    >>> as a reference. No real planes behave this way. If they did, they
    >>> would all have crashed on takeoff. I have played with the
    >>> sensitivities and null factors as well as P factor torque and scenery
    >>> settings. Nothing really helps. It seams that one problem is that the
    >>> flight model does not take into account the mass of the airplane so
    >>> that there is no rotational inertia in the yaw axis. Also there is a
    >>> delay between control input and effect which is not due to the
    >>> computer's processor speed. This all adds up to the PIO in the yaw
    >>> axis. I just hope that any wantabe pilots don't get discouraged and
    >>> never take real flight lessons due to their experience with MSFS.
    >>> Flying a real plane is much, much easier.
    >>>
    >>> Does anyone qualified to speak to this matter know what's wrong with
    >>> MS's flight model? Is there any way to correct this shortcoming?
    >>
    >> Well..I might be somewhat qualified on PIO having done some research
    >> testing in T38's on PIO along with inertia coupling and departures :-).
    >> Based on this and the constant testing I do with developers in the
    >> simulator, I have to tell you in all honesty that I have never noticed
    >> anything approaching a PIO symptom on my system and with my controllers
    >> in any axis.
    >> As a simple test data point, I think you have to conclude that if someone
    >> other than yourself isn't having the issues you are describing, the
    >> problem is most likely at your end somewhere and not latent in the
    >> simulator's programming.
    >> Dudley Henriques
    >>
    >
    >
  11. Archived from groups: alt.games.microsoft.flight-sim (More info?)

    Thank you everyone for answering my query re PIO. Gotta love this
    place.....learn something every day.

    Arthur

    "PilotJohn" <PilotJohn@forums.simradar.com> wrote in message
    news:1122595767.30535@forums.simradar.com...
    > PIO is Pilot Induced Oscillation. It is generally caused by
    > overcontrolling out of phase with the needed correction. It can be
    > made worse if there is a delay in the system so that the correction
    > doesn't happen immediately when the control input is made.
    >
    > _________________________________________________________
    > Posted via the -Web to Usenet- forums at http://forums.simradar.com
    > Visit www.simradar.com and try our Flight Simulation Search Engine!
  12. Archived from groups: alt.games.microsoft.flight-sim (More info?)

    Randy,
    Thanks. I think rudder pedals would probably be a big improvement over
    the twist stick. I'll give it a try.
    John

    _________________________________________________________
    Posted via the -Web to Usenet- forums at http://forums.simradar.com
    Visit www.simradar.com and try our Flight Simulation Search Engine!
  13. Archived from groups: alt.games.microsoft.flight-sim (More info?)

    Hi John and Oscar.
    Could it be caused you have not turned off the autorudder in the
    settings menu?

    Oskar Wagner wrote:
    > John, could you be more specific on the A/C involved (Stock or add-on etc.)
    > and the type of joystick used? To be honest I NEVER noticed PIO on yaw axis
    > during my whole MSFS career. PIO is as you know a combination of instability
    > and excessive pilot's inputs. So my first thought is of a indecent joystick
    > behaviour. A simple approach to that problem might be to use keyboard
    > commands and check the respective behaviour.
  14. Archived from groups: alt.games.microsoft.flight-sim (More info?)

    No, autorudder is off.

    _________________________________________________________
    Posted via the -Web to Usenet- forums at http://forums.simradar.com
    Visit www.simradar.com and try our Flight Simulation Search Engine!
  15. Archived from groups: alt.games.microsoft.flight-sim (More info?)

    Brilliant explanation as ever, Dudley! In addition to that I remember an
    issue we had on our Airbuses on roll control. Inexperienced pilots showed a
    strong tendency for PIO in gusty weather. According to investigations a
    common problem on most fly-by-wire A/C.
    --
    Oskar Wagner
    (retired Captain)

    Remember, in the great scheme of things, we're all small potatoes....
    "Dudley Henriques" <dhenriques@noware .net> schrieb im Newsbeitrag
    news:fDdGe.6506$6f.483@newsread3.news.atl.earthlink.net...
    > Hi Arthur;
    > PIO is an acronym for "pilot induced oscillation". Basically, without all
    > the aerodynamic explanation, it's what can happen if a pilot's corrective
    > action to an excursion by the airplane in any of the airplane's axis' gets
    > out of phase with the reaction caused by the control being used to
    > initiate input on that axis.
    > For example, the T38 Talon is an extremely high fuselage to wing ratio
    > (high fuselage mass ratio) aircraft. As such, and because it utilizes
    > irreversible hydraulic controls for pitch (stabilator), it's common in
    > this airplane to correct a pitch excursion up or down with a stick input
    > to the stab, then because the reaction to the input is so fast, a
    > corrective input to the initial input is initiated to correct again. The
    > result can be an out of phase condition that actually worsens the
    > situation. In other words you're correcting up when you should be
    > correcting down :-) This condition is so dangerous on final in the T38
    > that it's a know and listed issue in the dash 1 for the airplane.
    > The corrective action for a PIO condition in the T38 is to let go of the
    > stick to stabilize the airplane then reapply necessary pressure for the
    > flight condition.
    > PIO usually occurs on axis after an initial correction input has been
    > made. To put it simply, it's a correction to a correction that's out of
    > phase with the actual correction required.
    > PIO is usually found in high performance airplanes with extremely
    > sensitive controls like the T38. You can also find it in manual controls
    > such as found in a Pitts or an Extra. It's mostly found in pitch, but can
    > be an issue in any sensitive axis. The solution to handling PIO is trained
    > smoothness of control application.
    > Hope this helps a bit.
    > Dudley
    >
    > "Arthur" <alspectorz@rogers.com> wrote in message
    > news:W9SdnVAeMYJsxnTfRVn-ug@rogers.com...
    >> Would someone please elaborate on what PIO is? I have a general idea but
    >> am still not sure......I'm just a simmer, ya know : )
    >>
    >> Arthur
    >>
    >> "Dudley Henriques" <dhenriques@noware .net> wrote in message
    >> news:L0bGe.18542$aY6.13171@newsread1.news.atl.earthlink.net...
    >>>
    >>> "PilotJohn" <PilotJohn@forums.simradar.com> wrote in message
    >>> news:1122576742.30535@forums.simradar.com...
    >>>>I previously had the Win95 ver of MSFS (ver 6.0) and was disappointed
    >>>> in its performance. Ten years later I just installed the 2004 ver
    >>>> operating on a new fast computer running XP. The performance is still
    >>>> bad. I would have thought that after 10 years MS would have much
    >>>> improved the performance. As a pilot and servo engineer, I feel
    >>>> qualified to comment on one of its major shortcomings, namely
    >>>> instability in the yaw axis which causes PIO. The roll and pitch axes
    >>>> seem to perform reasonably, but not the yaw axis. This
    >>>> problem is most noticeable on the ground or pproaching the runway.
    >>>> It's not as noticeable in the air as there are no nearby objects to use
    >>>> as a reference. No real planes behave this way. If they did, they
    >>>> would all have crashed on takeoff. I have played with the
    >>>> sensitivities and null factors as well as P factor torque and scenery
    >>>> settings. Nothing really helps. It seams that one problem is that the
    >>>> flight model does not take into account the mass of the airplane so
    >>>> that there is no rotational inertia in the yaw axis. Also there is a
    >>>> delay between control input and effect which is not due to the
    >>>> computer's processor speed. This all adds up to the PIO in the yaw
    >>>> axis. I just hope that any wantabe pilots don't get discouraged and
    >>>> never take real flight lessons due to their experience with MSFS.
    >>>> Flying a real plane is much, much easier.
    >>>>
    >>>> Does anyone qualified to speak to this matter know what's wrong with
    >>>> MS's flight model? Is there any way to correct this shortcoming?
    >>>
    >>> Well..I might be somewhat qualified on PIO having done some research
    >>> testing in T38's on PIO along with inertia coupling and departures :-).
    >>> Based on this and the constant testing I do with developers in the
    >>> simulator, I have to tell you in all honesty that I have never noticed
    >>> anything approaching a PIO symptom on my system and with my controllers
    >>> in any axis.
    >>> As a simple test data point, I think you have to conclude that if
    >>> someone other than yourself isn't having the issues you are describing,
    >>> the problem is most likely at your end somewhere and not latent in the
    >>> simulator's programming.
    >>> Dudley Henriques
    >>>
    >>
    >>
    >
    >
  16. Archived from groups: alt.games.microsoft.flight-sim (More info?)

    Hi Oskar;
    Strangely enough, the only time I ever encountered PIO unintentionally was
    in pitch. One day many years ago I climbed out of the P51 after doing a demo
    and climbed into my friend's Christen Eagle to go check out in it. (big
    difference in control inputs :-)))
    I was used to the Pitts so I wasn't especially concentrating on my control
    technique which turned out to be a BIG mistake!!!.
    At altitude, going into my first maneuver I slammed hard into the first
    point of a four point roll and attempted to nail the knife edge exactly on
    target. I stopped the roll ok but WAY over controlled in forward pitch to
    hold the knife.....(stick travel in the Eagle this is about 1/2 inch :-) I
    went way negative and immediately corrected back. Doing this put me in a
    classic PIO scenario and for a few seconds there I was alternating positive
    to negative and back until I let go of it and it stabilized out for me.
    VERY embarrassing indeed!!!!! :-)))
    Dudley


    "Oskar Wagner" <rengaw@swissonline.ch> wrote in message
    news:dcbv20$aer$1@news.hispeed.ch...
    > Brilliant explanation as ever, Dudley! In addition to that I remember an
    > issue we had on our Airbuses on roll control. Inexperienced pilots showed
    > a strong tendency for PIO in gusty weather. According to investigations a
    > common problem on most fly-by-wire A/C.
    > --
    > Oskar Wagner
    > (retired Captain)
    >
    > Remember, in the great scheme of things, we're all small potatoes....
    > "Dudley Henriques" <dhenriques@noware .net> schrieb im Newsbeitrag
    > news:fDdGe.6506$6f.483@newsread3.news.atl.earthlink.net...
    >> Hi Arthur;
    >> PIO is an acronym for "pilot induced oscillation". Basically, without all
    >> the aerodynamic explanation, it's what can happen if a pilot's corrective
    >> action to an excursion by the airplane in any of the airplane's axis'
    >> gets out of phase with the reaction caused by the control being used to
    >> initiate input on that axis.
    >> For example, the T38 Talon is an extremely high fuselage to wing ratio
    >> (high fuselage mass ratio) aircraft. As such, and because it utilizes
    >> irreversible hydraulic controls for pitch (stabilator), it's common in
    >> this airplane to correct a pitch excursion up or down with a stick input
    >> to the stab, then because the reaction to the input is so fast, a
    >> corrective input to the initial input is initiated to correct again. The
    >> result can be an out of phase condition that actually worsens the
    >> situation. In other words you're correcting up when you should be
    >> correcting down :-) This condition is so dangerous on final in the T38
    >> that it's a know and listed issue in the dash 1 for the airplane.
    >> The corrective action for a PIO condition in the T38 is to let go of the
    >> stick to stabilize the airplane then reapply necessary pressure for the
    >> flight condition.
    >> PIO usually occurs on axis after an initial correction input has been
    >> made. To put it simply, it's a correction to a correction that's out of
    >> phase with the actual correction required.
    >> PIO is usually found in high performance airplanes with extremely
    >> sensitive controls like the T38. You can also find it in manual controls
    >> such as found in a Pitts or an Extra. It's mostly found in pitch, but can
    >> be an issue in any sensitive axis. The solution to handling PIO is
    >> trained smoothness of control application.
    >> Hope this helps a bit.
    >> Dudley
    >>
    >> "Arthur" <alspectorz@rogers.com> wrote in message
    >> news:W9SdnVAeMYJsxnTfRVn-ug@rogers.com...
    >>> Would someone please elaborate on what PIO is? I have a general idea
    >>> but am still not sure......I'm just a simmer, ya know : )
    >>>
    >>> Arthur
    >>>
    >>> "Dudley Henriques" <dhenriques@noware .net> wrote in message
    >>> news:L0bGe.18542$aY6.13171@newsread1.news.atl.earthlink.net...
    >>>>
    >>>> "PilotJohn" <PilotJohn@forums.simradar.com> wrote in message
    >>>> news:1122576742.30535@forums.simradar.com...
    >>>>>I previously had the Win95 ver of MSFS (ver 6.0) and was disappointed
    >>>>> in its performance. Ten years later I just installed the 2004 ver
    >>>>> operating on a new fast computer running XP. The performance is still
    >>>>> bad. I would have thought that after 10 years MS would have much
    >>>>> improved the performance. As a pilot and servo engineer, I feel
    >>>>> qualified to comment on one of its major shortcomings, namely
    >>>>> instability in the yaw axis which causes PIO. The roll and pitch axes
    >>>>> seem to perform reasonably, but not the yaw axis. This
    >>>>> problem is most noticeable on the ground or pproaching the runway.
    >>>>> It's not as noticeable in the air as there are no nearby objects to
    >>>>> use
    >>>>> as a reference. No real planes behave this way. If they did, they
    >>>>> would all have crashed on takeoff. I have played with the
    >>>>> sensitivities and null factors as well as P factor torque and scenery
    >>>>> settings. Nothing really helps. It seams that one problem is that
    >>>>> the
    >>>>> flight model does not take into account the mass of the airplane so
    >>>>> that there is no rotational inertia in the yaw axis. Also there is a
    >>>>> delay between control input and effect which is not due to the
    >>>>> computer's processor speed. This all adds up to the PIO in the yaw
    >>>>> axis. I just hope that any wantabe pilots don't get discouraged and
    >>>>> never take real flight lessons due to their experience with MSFS.
    >>>>> Flying a real plane is much, much easier.
    >>>>>
    >>>>> Does anyone qualified to speak to this matter know what's wrong with
    >>>>> MS's flight model? Is there any way to correct this shortcoming?
    >>>>
    >>>> Well..I might be somewhat qualified on PIO having done some research
    >>>> testing in T38's on PIO along with inertia coupling and departures :-).
    >>>> Based on this and the constant testing I do with developers in the
    >>>> simulator, I have to tell you in all honesty that I have never noticed
    >>>> anything approaching a PIO symptom on my system and with my controllers
    >>>> in any axis.
    >>>> As a simple test data point, I think you have to conclude that if
    >>>> someone other than yourself isn't having the issues you are describing,
    >>>> the problem is most likely at your end somewhere and not latent in the
    >>>> simulator's programming.
    >>>> Dudley Henriques
    >>>>
    >>>
    >>>
    >>
    >>
    >
    >
  17. Archived from groups: alt.games.microsoft.flight-sim (More info?)

    "PilotJohn" <PilotJohn@forums.simradar.com> wrote in message
    news:1122611798.30535@forums.simradar.com...
    > Randy,
    > Thanks. I think rudder pedals would probably be a big improvement over
    > the twist stick. I'll give it a try.
    > John

    I know I'm a couple of days late, but I was out of town. Went to
    Minnesota and spent a couple of days at a lake!

    You're using a twist stick? Try turning off the rudder channel of the
    stick and turning on ARI. Known in FS9 as "autorudder"...<G>


    --
    Earl Needham
    Clovis, New Mexico USA
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