[NSRCA-discussion] the joy of trimming , left rudder tuck downline pulls
shinden1 at cox.net
shinden1 at cox.net
Mon Mar 10 19:28:26 AKDT 2008
Derek
all airplanes out there except for May-be ,Nat`s and Mine,, have this problem people just learn to fly around it or mix it out SO,
Do the same thing I advised Chad to do
at least 1/2 pos on the wing ....may require slightly more
1/4 pos on the stab ,,<btw the adjustable stab myth to fix a downline pull or tuck has been around for a long time,, stab adjustment does no more than ,, a thrust adjustment for this problem you may get a click from the stab being cambered one way or the other >the elevators and stab do essentially the same thing steer the wing,, so if you adjust the stab the set up on the wing will require you to compensate for the stab adjustment by guess what,, trimming the elevator once you fly the airplane again for level flight ,and you still have your pull problem,,
BTW ,,I wonder Why no one ever complains about pulling to the belly in the downlines ,,,,because no one uses more that 1/2 deg positive <G>
NOW !! the 1/4 deg pos.on the stab is just adjusted so it don`t look like you are carrying down trim.although it has some effect on the expo curve if you leave it a zero and it solidifies the inverted elevator touch we look for.
Again,you may have to move your weight forward to fix left rudder mix issues after you adjust you wing But probably not ,,Because most people fly with a click or two of down trim in level flight to split the difference in the vertical.
take your time keep notes and report back to the list Please <G>
Bryan
---- Derek Koopowitz <derekkoopowitz at gmail.com> wrote:
> Do you think you could do this before Friday? LOL
>
> I have a similar problem except mine just pulls to the canopy on both
> up/downlines. I changed stab incidence to try and correct the downline pull
> and it seemed to make it worse. I reset it... and now that I'm home I will
> use my incidence meter to check wing and stab. I intend to go to zero on
> stab (if it isn't there now) and then go positive on the wing.
>
>
> -----Original Message-----
> From: nsrca-discussion-bounces at lists.nsrca.org
> [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Chad
> Northeast
> Sent: Monday, March 10, 2008 7:23 PM
> To: NSRCA Mailing List
> Subject: Re: [NSRCA-discussion] the joy of trimming , left rudder tuck
> downline pulls
>
> Ok boys, I will print off (because I would probably forget otherwise) and
> take both Nat's and Bryan's suggestions with me to the field and have at 'er
> :) Since they are different ideas to fix the same problem it will be
> interesting to see which one (or maybe both?) work!
>
> I know for a fact that more incidence and nose weight remove the left rudder
> KE mix.
>
> I am gong to be in Owego, NY from Wed to next Tues though so it will have to
> wait until I am back. My wife will kill me if I go flying tomorrow LOL :)
>
> Chad
>
> shinden1 at cox.net wrote:
> > Right on target Matt !
> > Bryan
> > ---- Matthew Frederick <mjfrederick at cox.net> wrote:
> >
> >> I must be getting the hang of this... first thing I thought was add a
> >> little incidence in the wing. Even though the down thrust is a bit
> >> much... Like Bryan says all the time: wing incidence trumps it all.
> >> CG, thrust, and stab incidence are used for extreme fine tuning. You
> >> gotta get that incidence right first...
> >>
> >> Matt
> >> ----- Original Message -----
> >> From: <shinden1 at cox.net>
> >> To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
> >> Sent: Monday, March 10, 2008 7:31 PM
> >> Subject: [NSRCA-discussion] the joy of trimming ,left rudder tuck
> >> downline pulls
> >>
> >>
> >>
> >>> 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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