In the real thing, stall is actually a fairly benign event. There is =
some
rather exciting pitch-down when stalling it flaps down but the g-break =
(your
"breaks loose") is not pronounced at all.
I found it quite disappointing.
Also, some 172's have rudder trim but many do not. The typical practice =
is
to manually bend the rudder trim tab (on the ground) to achieve =
hands-off
straight and level flight in cruise. As far as I know, none of the =
172's
have aileron trim.
-----Original Message-----
From: jsbsim-devel-bounces@...
[mailto:jsbsim-devel-bounces@...] On Behalf Of Tony =
Pelton
Sent: Sunday, June 18, 2006 11:13 AM
To: JSBSim development issues
Subject: Re: [Jsbsim-devel] Which of the small prop planes included =
injsbsim
isthe best
On 6/18/06, Jon S. Berndt <jsb@...> wrote:
> > Thanks Jon for the velocities definition. That really helps
> >
> > We are using c172p now to test connection between msfs and jsbsim,=20
> > but it seems that rolling is very strange in this plane. The roll=20
> > angle keep increasing when aileron FCS is centered. That is not the=20
> > case with default C172
> >
> > Which plane is the best to use from the distribution (from single=20
> > engine
> > ones) ?
>
> The C172p (or maybe the "r"?) is a good one. The aircraft will roll to =
> the left - especially at takeoff - because of p-factor and because of=20
> the torque created by the engine. You need to use roll trim. I'm not=20
> sure how to do that in FlightGear.
i use rudder trim for the c172p myself.
a bit of my joystick config included at the end of this e-mail.
i've noticed that c172p model, out of the box in FG, has some aileron =
trim
already configured by default, such that the model should be stable in
cruise ?
a snip from the "-set" config in FG ...
-- snip --
<!-- trim for level cruise -->
<controls>
<flight>
<aileron-trim>0.027</aileron-trim>
<rudder-trim>0.0</rudder-trim>
</flight>
-- snip --
i am not a pilot in real life, but if this class of aircraft has trim at
all, wouldn't it be most likely that it would have rudder trim, and =
that, as
the model is in FG, that the airplane would be "hard trimmed" manually =
for
straight-n-level in cruise ?
also, Tony Peden asked about self righting i think ?
my observation, especially at higher AoA, with power on, such as in best
climb, the model would roll right over without hand holding.
not sure what is suppossed to happen there.
i've also noted, while trying to stall the model, such as on hard flare =
for
touchdown, that the model doesn't really seem to stall in an obvious =
way.
instead, it seems like AoA just keeps increasing, and it seems =
impossible to
keep the model from entering into a descending trend, but it doesn't =
really
"break loose" from lift.
my observation, with my "extensive" (2) hours in a RL 172, and observing =
how
the the x-plane fdm seems to work, is that wing stall is a much more
pronounced event.
$0.02, and grain of salt, as this is just based on a little bit of
unscientific playing around in FG.
Tony
-- snip joystick config --
<button>
<desc>rudder trim right</desc>
<number>
<unix>11</unix>
<mac>1</mac>
<windows>1</windows>
</number>
<repeatable type=3D"bool">true</repeatable>
<binding>
<command>property-adjust</command>
<property>/controls/flight/rudder-trim</property>
<step>0.001</step>
</binding>
</button>
<button>
<desc>rudder trim left</desc>
<number>
<unix>10</unix>
<mac>1</mac>
<windows>1</windows>
</number>
<repeatable type=3D"bool">true</repeatable>
<binding>
<command>property-adjust</command>
<property>/controls/flight/rudder-trim</property>
<step>-0.001</step>
</binding>
</button>
--=20
X-SA user ? 0.5.1 is out !
XData 0.1 for X-SA is out !
http://x-plane.dsrts.com
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