Zn-Line Alliance trimming question

[John Pavlick]

Peter,
 Forgive my ignorance - I am returning to pattern flying after a long hiatus
so I'm not familiar with the design (Alliance). Is the rudder hinge line
exactly perpendicular to the thrust line? Most of the "new style" pattern
ships seem to be this way but...  in the old days I remember designs that
had the rudder hinge line canted forward or back. This will of course change
the way the plane pitches in knife edge flight. In addition to this, the
shape of the rudder can cause similar problems. It's odd that your vertical
maneuvers are OK. I don't know about wing incidence but you can usually rule
that out with some other simple trim tests (power OFF vertical dive). If
this shows signs of not being correct, the thing to look for would be "too
much incidence". It sounds like you have already covered this though. The
only other "trick" you might try is trimming both ailerons up a little bit.
Maybe someone more knowledgeable (and up-to-date) can answer your question,
but I'd be interested in the answer as well.

John Pavlick
http://www.idseng.com


  -----Original Message-----
  From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On
Behalf Of Peter Pennisi
  Sent: Sunday, August 22, 2004 7:30 AM
  To: discussion at nsrca.org
  Subject: Zn-Line Alliance trimming question


    Hey Guys,



    I am starting to get a few flights under my belt with this model. I am
happy with the way the model performs in most areas except in rolls were
rudder is being used. My model suffers from severe pitching to belly in
knife edge. I think I am running about 17% on both left and right rudder.
Mind you I fly soft so it isn’t as bad as it sounds. It is about 1/8th inch
up elevator on full rudder.



    My problem is I am finding it difficult to roll cleanly for example in
reversed point rolls. My old model would do this without a problem (That
sort of excludes my ability being the problem). Whenever I touch the rudder
in any part of the roll the model gets all out of shape. If I roll
vertically either continuously or point rolls the model tracks perfectly.



    The CG is exactly were CPLR runs his and the elevator trims neutral. The
model also dives and climbs perfectly straight.



    Anyone have any experience with this design?



    Why does this design pitch so badly in knife edge?



    Can wing incidence be an issue here?





    Regards,




    Peter


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