wing tip shape (now Knife Edge Trimming!)

[Keith Black]

OK, now I'll rant about the mixing issue. I understand that the "ideal" plane should not require any mixing rudder to elevator or ailerons. But if your plane has those bad tendencies I say MIX THEM OUT! Jeeze, why do you want to make your job harder based on some philosophical problem with using computer mixing? Hey, does the stealth bomber have any mixing? How awful if it does, we should turn that off and let the pilots deal with it manually!!!

OK, I know that's ridiculous, but my point is that I think it's silly to avoid mixing just because the plane "shouldn't" need it.

Some will argue that any mixing you do to correct one problem will cause problems in other conditions. In some cases this may be true, and I certainly wouldn't leave the plane completely out of alignment and try to compensate for a crooked plane with mixes, but a tuck here, a nip there... wait that's the cosmetic surgery rant... what I mean is if your plane tucks, pulls or rolls with rudder... mix it out! Then buy a new plane in hopes that it will be perfect, then when it's not, put in the mixes again and never admit it ;-)

Keith Black

----- Original Message ----- 
  From: Ted Sander 
  To: discussion at nsrca.org 
  Sent: Friday, November 26, 2004 6:01 PM
  Subject: RE: wing tip shape (now Knife Edge Trimming!)


  Geez, this subject just keeps morphing!  Matt caused it! <grin>

   I swept away the wreckage of my Funtana 90 to work on my new wing today.   The story was:

  2 ½ flights on this new ARF this past summer.  Generally very nice flyer, except there was modest roll and a tremendous amount of down (wheels) pitch with rudder.  Flutter got me coming out of a stall turn (horns were a tad too short as compared to servo arms), stripped both aileron servos.  Cut the throttle, and tried to make a flat left turn back to the field.  Plane pitched down radically, I pulled up in reaction, you can guess the rest..



  I knew I should have mixed in a lot of up to rudder.  But what would have been valid mechanical changes to trim out the pitching?  Lower the stab?  Play with incidence (verticals were pretty straight)?  I might even buy another, and be more conservative in setup - but only if there are some ways to tackle the pitching problem beyond mixing.  Any advice?



  Ted



  -----Original Message-----
  From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org] On Behalf Of Rcmaster199 at aol.com
  Sent: Friday, November 26, 2004 12:28 PM
  To: discussion at nsrca.org
  Subject: Re: wing tip shape (now surface hinging)



  NO!!! REALLY???? GEEZ I DIDN'T KNOW THAT (jus' kiddin' Keith, and pokin' a little fun)



  With the kind of geewhiz programmability available nowadays, too many of us have become a little complacent and use the electronic fixes as cure alls. I am old school and prefer to make the mechanical set-up as sound as possible first, then use the radio to trim the mechanical set-up if needed. If it needs more than a few percent electronic fixing, I usually re-do the mechanical set-up in my pattern models. I do not subscribe to electronic fixes for everything! (Sport planes are another matter)



  Having to electronically fix knife edge flight for example, just frosts me, particularly when a kit costs over $1000 in some cases. 



  MattK


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