[NSRCA-discussion] the joy of trim

[Chad Northeast]

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