<DIV>I have to ask . . . . . what is the difference between adding positice incidence to the wing versus negative to the stab? Are they not relative? <BR><BR><B><I>Dean Pappas <d.pappas@kodeos.com></I></B> wrote:
<BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">Hi again Paul,<BR>Many planes trim nicely with a small amount of positive incidence in the wing, compared to the stab.<BR>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.<BR><BR>Before doing that, are you sure that the ailerons aren't both trailed up or down, even a little?<BR><BR>Don't let us forget you, until this problem is licked,<BR>Dean<BR><BR>-----Original Message-----<BR>From: David Lockhart [mailto:DaveL322@comcast.net]<BR>Sent: Monday, March 29, 2004 11:06 AM<BR>To:
discussion@nsrca.org<BR>Subject: Re: Trimming Help<BR><BR><BR>Paul,<BR><BR>Most of the trim advice being given is based (rightly so) on some<BR>assumptions -<BR>- the plane is straight and true,<BR>- ail hinges are sealed,<BR>- servos are tracking evenly throughout the range of throw (as measured by a<BR>throw meter - Budd Laser, CRC, Ivans Gadget, etc),<BR>- all references to ail throw and ail differential refer to actual measured<BR>throw at the aileron (as opposed to an ATV/endpoint/differential setting in<BR>the radio).<BR><BR>Another thing I would suggest - if possible, have another experienced<BR>pattern pilot fly the plane and see if they find the same problem - and it<BR>gives you an opportunity to very critcically watch the plane and evaluate<BR>without needing to concentrate on the actual flying.<BR><BR>As Dean P said, negative ail differential is rarely needed, but not out of<BR>the question. Most of my planes end up with no differential, or a very<BR>slight amount of
positive differential - but I did have one that required<BR>negative differential.<BR><BR>Good luck,<BR><BR>Dave Lockhart<BR>DaveL322@comcast.net<BR><BR><BR><BR>----- Original Message -----<BR>From: "Paul Lawrence" <PWL45@YAHOO.COM><BR>To: <DISCUSSION@NSRCA.ORG><BR>Sent: Monday, March 29, 2004 8:19 AM<BR>Subject: RE: Trimming Help<BR><BR><BR>> The plane is a Tai Ji 60. I may have found an<BR>> incidence<BR>> problem too. I don't really know where the reference<BR>> line is for this model and I am also still learning<BR>> how to check incidence, but if I block up the plane<BR>> and get the wings at 0 degrees and then check the<BR>> stab, it is showing -1 degree of incidence. That seems<BR>> excessive.<BR>><BR>> I'm flying Intermediate and the yaw really shows up on<BR>> the humpty bump and full roll up on stall turn. When I<BR>> perform the humpty bump, I pull to vertical, 1/2 roll<BR>> right and the plane heads off to the left(belly
in).<BR>> On the full roll up, the plane heads off to the right<BR>> after rolling right.<BR>><BR>> So far, I have received a lot of good advice and have<BR>> several things to try. Thanks.<BR>><BR>><BR>><BR>> ><BR>> > -----Original Message-----<BR>> > From: Paul Lawrence [mailto:pwl45@yahoo.com]<BR>> > Sent: Sun 3/28/2004 10:33 PM<BR>> > To: discussion@nsrca.org<BR>> > Cc:<BR>> > Subject: Trimming Help<BR>> ><BR>> ><BR>> > After getting soundly beat in Ocala last weekend, I<BR>> > realized that I have been getting proverse yaw as my<BR>> > plane rolls.<BR>> > It wasn't evident until I saw other well-trimmed<BR>> > planes flying.<BR>> > The plane yaws in the direction of roll input and I<BR>> > have been experimenting with a multitude of aileron<BR>> > differential settings and can't seem to remove the<BR>> > yaw.<BR>> > With zero differential,
the plane still yaws in the<BR>> > direction of roll.<BR>> > The trimming chart says to reduce differential in<BR>> > this condition, but I have reduced it to zero.<BR>> > Should I program in negative differential(doesn't<BR>> > sound good) or should I program a litle bit of<BR>> > opposite rudder correction to offset the proverse<BR>> > yaw?<BR>> ><BR>> > Also, does CG and Incidence affect adverse or<BR>> > proverse yaw while rolling?<BR>> > The plane was a little nose heavy and I have also<BR>> > been adding tail weight to try and clean up the<BR>> > rolls, but still can't get that yaw out of the<BR>> > rolls.<BR>> ><BR>> ><BR>> ><BR>><BR>> =====================================<BR>> # To be removed from this list, go to http://www.nsrca.org/discussionA.htm<BR>> and follow the instructions.<BR>><BR><BR>=====================================<BR># To be removed from
this list, go to http://www.nsrca.org/discussionA.htm<BR>and follow the instructions.<BR><BR>====================================# To be removed from this list, go to http://www.nsrca.org/discussionA.htm<BR>and follow the instructions.<BR></BLOCKQUOTE></DIV><BR><BR>Bob Kane<br>getterflash@yahoo.com<p><hr size=1><font face=arial size=-1>Do you Yahoo!?<br>
<a href="http://taxes.yahoo.com/filing.html"><b>Yahoo! Finance Tax Center</a></b> - File online. File on time.