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General control line discussion => Open Forum => Topic started by: Kim Mortimore on September 11, 2012, 05:29:12 PM
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I'd like to review the trim problems caused by leadouts too far forward and those caused by too far back. The old memory ain't what it used to be. Does anyone who can rattle them off want to do so? I'm guessin' I'm not the onlyest feller what can use this here review. Thanks in advance.
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Too far back, loose lines up high. Too far forward, really odd wiggles when you do a square corner. Move leadouts no more than 1/8 in at a time.
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Reading the "fine print" of PW's trim flow chart will help. If you can get a copy of the Impact article, that will also help.
Take advantage of all changes to try other changes. I got some advise to try moving the LO's forward on a model. It didn't help, so I was going to put it back where it was. But it struck me that while the LO's were too far forward, I ought to try moving the CG forward. I didn't like that either, but I learned something, and used some logical thinking (for a change). Another idea, if you try a heavier prop (APC, Graupner, etc.), also try adding a little tail weight to put the CG in the same place. That will tell you if the prop is 100% of the improvement, or maybe part of it is the CG shift?
Bruce Perry was suffering with a poor groove on his 1st Jester, and re-read the Impact article, leading him to move the LO's back a smidge, and correcting the problem.
I came across this Brett Buck article, and attached it for you. H^^ Steve
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Well, those things mentioned are the major changes to expect with the caveat that the CG certainly affects the position of the leadouts.
One other thing not often mentioned is that leadout position changes does affect neutral trim. Small changes may go unnoticed but large changes certainly will not. Sliding the leadout adjuster rotates the bellcrank and that affects the neutral trim,
Also of lesser note is that moving the leadouts aft makes the airplane more sensitive to down inputs and less sensitive to up inputs. Once again small changes may go unnoticed but large ones will not. If you think not slide your adjuster all the way to the rear and fly the airplane...be careful it can be most disappointing.
Randy Cuberly
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This makes me think of the days when I would be trying to trim an RC plane of all things. Was told to make a change to correct something, go more than you think you need. If it helps too much then back it up a little until you get it where you want it. From experience, sometimes the change you make is not the change that should have been done.
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One point that can be overlooked is to make sure the Adj. Guide is "tight" before you fly. I also make sure the screw cannot back out of the guide. I had this happen once at a contest. Made for a very interesting flight!
BIG Bear
RNMM/AMM
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One point that can be overlooked is to make sure the Adj. Guide is "tight" before you fly. I also make sure the screw cannot back out of the guide. I had this happen once at a contest. Made for a very interesting flight!
BIG Bear
RNMM/AMM
Bill,
Oh yeah, the In-Flight Leadout Randomizer. LL~