[NSRCA-discussion] the joy of trimming , left rudder tuck downline pulls
shinden1 at cox.net
shinden1 at cox.net
Tue Mar 11 10:56:48 AKDT 2008
Don I will have a complete response tonight
along with the" Hebert traingulation method" for perfect trimming,
I know it gets confusing sometimes but I`ll try to explain it a little better tonight
Bryan
---- Don Ramsey <donramsey at gmail.com> wrote:
> I'm with Jim in not understand the reason some of the incidence changes
> work. Consider increasing the incidence for adjusting the push to the belly
> in knife edge. My reasoning would be; increase the incidence, put in some
> down elevator to fly straight and level. Roll to knife edge and the model
> would then push to the belly more severely. What am I missing?
>
> Don
>
> -----Original Message-----
> From: nsrca-discussion-bounces at lists.nsrca.org
> [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of James Oddino
> Sent: Tuesday, March 11, 2008 10:59 AM
> To: NSRCA Mailing List
> Subject: Re: [NSRCA-discussion] the joy of trimming , left rudder tuck
> downline pulls
>
> Bryan,
>
> I'm trying to figure out how increasing the wing incidence, I assume
> with respect to the fuselage, will get rid of a pull to the canopy on
> a vertical downline. Is it because you need to crank in some down
> trim to make it fly level? Or is it because the tail flies higher in
> level flight and the higher vertical cg creates a couple pushing the
> nose down during the vertical downline?
>
> I assume that if one could achieve a good vertical downline with power
> off, he could then adjust the thrust to get a good vertical upline?
> It would seem that the thrust is part of what made it fly level and
> you would get into an endless loop chasing things around. What is the
> sequence for getting what you want?
>
> I adjust the relation between the downthrust and wing to get a good
> vertical upline and trim out the pull in the downline like Chad. Tell
> us how we can get a combination of vertical up with power, level with
> power (less power?) and vertical down without power that are all good
> without throttle to elevator trim.
>
> Jim O
>
>
> On Mar 10, 2008, at 5:31 PM, <shinden1 at cox.net> <shinden1 at cox.net>
> wrote:
>
> > 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
> >>>
> >>> _______________________________________________
> >>> NSRCA-discussion mailing list
> >>> NSRCA-discussion at lists.nsrca.org
> >>> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
> >>>
> >>
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