[NSRCA-discussion] the joy of trim

[shinden1 at cox.net]

Now,, we have the Harrison trim method <G>
Bryan
---- "Dr. Mike Harrison" <drmikedds at sbcglobal.net> wrote: 
> Chad, hold a little up elevator!
> ----- Original Message ----- 
> From: "Chad Northeast" <chadnortheast at shaw.ca>
> To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
> Sent: Monday, March 10, 2008 4:57 PM
> Subject: Re: [NSRCA-discussion] the joy of trim
> 
> 
> > Ok you trim masters, here is a tricky one for you.
> >
> > Bryan and I have been through this a bit last year but I ran out of time 
> > before the Worlds to fix it and just flew with what I had.
> >
> > On my Twister I have this pesky problem, the setup is like so,
> >
> > wing = 1/2+ Bryans suggestion and I like it
> > stab = 0
> > motor = factory claims 2.5 down, have not measured but could if asked, I 
> > have added more to cure a problem see below
> > CG = has been anywhere from 275 to 300mm from TE mostly with the same 
> > result.  Currently its around 285-290 and it feels good at that point.  45 
> > ups inverted track almost hands off if under enough power.
> >
> > Symptoms,
> >
> > Plane flies well, at this setup I need 0 mix right rudder to ele in knife, 
> > and about 2% up ele with left rudder in knife,
> > about 1/32" down elevator with idle to fix a downline
> > Added downthrust as the increase in wing inc. and more forward CG really 
> > helped the mix in knife and made rollers easier, but forced an increase in 
> > downthrust as the plane started pulling to the canopy on uplines. 
> > Downline mix remained the same.
> >
> > The big problem I cannot resolve is this, a 45 deg down upright (motor at 
> > idle) the plane pitches to the belly and will not track on its own for any 
> > length of time.  If I switch the idle-down mix off its rock solid on that 
> > line.
> >
> > I am open to all suggestions now that I have a bit of time to play with 
> > this, I hope Bryan chimes in some more as I would like to continue where 
> > we left off last fall.  If you suggest something I will do my best to give 
> > it a go and let you know how it works (provided it doesn't snow!)
> >
> > The plane is basically super locked in with this setup, except for the 
> > silly 45 down upright, which is a problem in cubans and such.
> >
> > Comments and thoughts from the masters are most appreciated :)  I consider 
> > myself one of the, cant really trim that well but can fly through it just 
> > fine types :)
> >
> > Chad
> >
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> 
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