Trimming Help

[Paul Lawrence]

Thanks for all the suggestions. I can't wait to go
flying again to do some experimenting.

--- Dean Pappas <d.pappas at kodeos.com> wrote:
> Hi again Paul,
> Many planes trim nicely with  a small amount of
> positive incidence in the wing, compared to the
> stab.
> The typical amount is about 1/4 to 1/3 degree, or a
> little over 1/16" over the wing chord. If you have
> full degree of incidence in the wing, you may have a
> belly-pitch in knife edge, unless terribly
> nose-heavy. Now we need to ask those of you out
> there with well trimmed Tai-Ji to tell us where your
> CG is. There's no sense in re-inventing the wheel.
> Put the CG there, and adjust/shim the incidence
> 'till the elevator trim goes away, and let's see
> where we are.
> 
> Before doing that, are you sure that the ailerons
> aren't both trailed up or down, even a little?
> 
> Don't let us forget you, until this problem is
> licked,
> 	Dean
> 
> -----Original Message-----
> From: David Lockhart [mailto:DaveL322 at comcast.net]
> Sent: Monday, March 29, 2004 11:06 AM
> To: discussion at nsrca.org
> Subject: Re: Trimming Help
> 
> 
> Paul,
> 
> Most of the trim advice being given is based
> (rightly so) on some
> assumptions -
> - the plane is straight and true,
> - ail hinges are sealed,
> - servos are tracking evenly throughout the range of
> throw (as measured by a
> throw meter - Budd Laser, CRC, Ivans Gadget, etc),
> - all references to ail throw and ail differential
> refer to actual measured
> throw at the aileron (as opposed to an
> ATV/endpoint/differential setting in
> the radio).
> 
> Another thing I would suggest - if possible, have
> another experienced
> pattern pilot fly the plane and see if they find the
> same problem - and it
> gives you an opportunity to very critcically watch
> the plane and evaluate
> without needing to concentrate on the actual flying.
> 
> As Dean P said, negative ail differential is rarely
> needed, but not out of
> the question.  Most of my planes end up with no
> differential, or a very
> slight amount of positive differential - but I did
> have one that required
> negative differential.
> 
> Good luck,
> 
> Dave Lockhart
> DaveL322 at comcast.net
> 
> 
> 
> ----- Original Message -----
> From: "Paul Lawrence" <pwl45 at yahoo.com>
> To: <discussion at nsrca.org>
> Sent: Monday, March 29, 2004 8:19 AM
> Subject: RE: Trimming Help
> 
> 
> > The plane is a Tai Ji 60. I may have found an
> > incidence
> > problem too. I don't really know where the
> reference
> > line is for this model and I am also still
> learning
> > how to check incidence, but if I block up the
> plane
> > and get the wings at 0 degrees and then check the
> > stab, it is showing -1 degree of incidence. That
> seems
> > excessive.
> >
> > I'm flying Intermediate and the yaw really shows
> up on
> > the humpty bump and full roll up on stall turn.
> When I
> > perform the humpty bump, I pull to vertical, 1/2
> roll
> > right and the plane heads off to the left(belly
> in).
> > On the full roll up, the plane heads off to the
> right
> > after rolling right.
> >
> > So far, I have received a lot of good advice and
> have
> > several things to try. Thanks.
> >
> >
> >
> > >
> > > -----Original Message-----
> > > From: Paul Lawrence [mailto:pwl45 at yahoo.com]
> > > Sent: Sun 3/28/2004 10:33 PM
> > > To: discussion at nsrca.org
> > > Cc:
> > > Subject: Trimming Help
> > >
> > >
> > > After getting soundly beat in Ocala last
> weekend, I
> > > realized that I have been getting proverse yaw
> as my
> > > plane rolls.
> > > It wasn't evident until I saw other well-trimmed
> > > planes flying.
> > > The plane yaws in the direction of roll input
> and I
> > > have been experimenting with a multitude of
> aileron
> > > differential settings and can't seem to remove
> the
> > > yaw.
> > > With zero differential, the plane still yaws in
> the
> > > direction of roll.
> > > The trimming chart says to reduce differential
> in
> > > this condition, but I have reduced it to zero.
> > > Should I program in negative
> differential(doesn't
> > > sound good) or should I program a litle bit of
> > > opposite rudder correction to offset the
> proverse
> > > yaw?
> > >
> > > Also, does CG and Incidence affect adverse or
> > > proverse yaw while rolling?
> > > The plane was a little nose heavy and I have
> also
> > > been adding tail weight to try and clean up the
> > > rolls, but still can't get that yaw out of the
> > > rolls.
> > >
> > >
> > >
> >
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> >
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