[NSRCA-discussion] the joy of trimming , left rudder tuck downline pulls

[shinden1 at cox.net]

Chad having a small tuck to the belly on left rudder only,,
  is always a result in a little too much tail weight  ,,providing the stab halves and elevator halves are correct.
thats whats happening in your wandering 4/5`s
 the tail weight as is ,,is making you add a little down elevator trim because  the wing is flying a little more positive.
You want to create the pos angle of attack with the wing only use the tail weight only to adjust the feel for rolls and inverted flight.
engine thrust is contributory But ,not doing anything in the left knife edge.
it would be happening in the right rudder too.
sorry Nat.. 
approach  it like this, before you reset the down thrust ,,,because we want to know what really fixed it 
increase the wing inc 1/32 "  more positive  or till it stopps pulling in the downline , some airplane require the wing  more than 1/2 deg  depending on weight and airfoils 1/2 pos. is not a hard deck and you will have to move the cg forward to remove the left rudder knife mix ,,move it till you find a sweet spot , between downlines and both knife edges.
, Always remember tail heavy makes the elevator and rudder  sensitive  and nose wweightmakes them a little numb but  much more effective 
 your spins,snaps entry and exits ,, up and downline,45`s will be corrected 
you will also see improvement in the wind due to the forward c/g and pos inc. add pos wing inc till it stops pulling to the canopy in the downs 
and let us know what happens 
Bryan
darn now I have given away the family secrets ,And
I have just made it harder to beat Chad <G>

---- Nat Penton <natpenton at centurytel.net> wrote: 
> Chad
> Your  problem is caused by the large difference between T/L and wing. Reduce 
> the downthrust by 1 deg and reduce the wing incidence by 1 deg , and test.
> 
> We will go from there.
> 
> Your excess downthrust requires up elev trim when under power. You need to 
> adjust wing and T/L to avoid other problems. If you just lower the wing inc 
> it will go to the belly in knife. If you just reduce the D/T it will go to 
> the canopy in knife.                                                  Nat
> 
> ----- Original Message ----- 
> From: "Chad Northeast" <chadnortheast at shaw.ca>
> To: "NSRCA Mailing List" <nsrca-discussion at lists.f3a.us>
> 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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