[NSRCA-discussion] triangulation trimming
shinden1 at cox.net
shinden1 at cox.net
Tue Mar 11 20:54:40 AKDT 2008
I`m all for it
Bryan
---- Matthew Frederick <mjfrederick at cox.net> wrote:
> Chris and Bryan,
>
> I'd be happy to help edit this for a K-Factor issue. Since I fly with Bryan
> I have a good insight to his thought process, and it would be easy for me to
> clean this up.
>
> Matt
> ----- Original Message -----
> From: <shinden1 at cox.net>
> To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
> Sent: Tuesday, March 11, 2008 10:05 PM
> Subject: [NSRCA-discussion] triangulation trimming
>
>
> > triangulation trimming,
> > this is going to be long winded,
> > I want to preface this discussion by saying I have learned a great deal
> > from Dean Pappas one of my hero`s in the sport,,Jim Oddino I read these
> > guys all the time ,,Nat Penton ,,I learned a great deal about painting
> > from Mike Harrison who is always willing to tell you what he knows <G> and
> > I have looked up to Earl Haury as an all around Teacher and appreciate
> > those guys for their hard work in the sport ahead of me and willingness
> > to share what they know.
> > Now let me say I am no flight engineer or aerodynamic Guru , I`ll leave
> > that title to Nat Penton as he deserves it, But the two guys that started
> > this flying madness were,, by cycle mechanics,as we all know .
> > so I`m in good company
> > After trimming over 15 of my own designs and trimming and building two
> > or three airplanes a year for about 20 years I have a lot of practical
> > knowledge on this subject matter and have kept notes. to verify my
> > observations I hope this will help.
> > A better Flyer with more experience will be a better trimmer because he
> > demands more from his airplane ,,but being a better trimmer will earn you
> > better flying skills .
> > so here we go
> > Mike ,Keith, Jim and Don, thank you for your patience
> >
> > For the purpose of this discussion tail heavy nose heavy is relative to
> > the recommended C/G and not always an extreme position just a way to
> > example it.
> >
> > If you are using a 0-0 setup things may- be alittle different as to what I
> > say and what you see on your airplanes as you fly them
> > my set up and your set up are not to be equated with each other.
> > and I think that's where some of the confusion comes in you having only
> > experienced your set ups.
> > However ,,left rudder tuck is a symptom of the airplane being tail heavy
> > on all pattern models no matter the set up, as long as the stab and
> > elevators are accurately adjusted , Extreme tail heavy will mean both
> > knifes will tuck to the belly. it is just a symptom that tells me the cure
> > and allows me to diagnose trim problems <see my reply to Chad>
> > Jim O,
> > Any wing has to produce lift, to fly and there are two ways to do it, add
> > pos inc to the wing according to the datum line on the fuse My Method
> > or,, add pos inc to the fuse, the 0-0 method ,,,by this I mean , flying
> > the airplane a little tail heavy to achieve pos inc ,, there is no way
> > around it ,the wing has to have a pos angle of attack to produce lift and
> > fly level and lift 11 pounds of balsa and Glass.
> > vertical c/g has no factor on this discussion I don`t understand enough
> > about it to discuss it,{G}
> > The stab does not induce the lift ,,it controls the lift of the wing and
> > steers the wing and fuse. {no arguments here please I`m trying to make
> > the bigger picture I know it does contribute lift and share the lift
> > load,}
> >
> > A ,0-0 or sub 1/2pos set up will cause some or all of these problems
> > ,,for you guys set up 0-0 ,, check um off ,,,
> > A tuck to the belly on left rudder {or both depending on how tail heavy}
> > more tail heavy more tuck ,,pull in both up and down lines ,,,So now we
> > add down thrust to fix one problem upline pull { as as Jim and others
> > observed and suggested } and it magnifies the others. like Nat explained
> > to Chad ,,,and now it may give a differential problem . so we address
> > that with the radio.by mixing
> > and this occurs,,
> > stalls may be hard to do because,, "mix dont go away ", Snaps and spins
> > are hard to perform correctly start,,stop consistently ,and they wander
> > off line in the uplines,and 4/5`s so you see flyers using opposite rudder
> > to lead before, and after to keep them on line , and even more apparently
> > worse in a upline ,,, you can`t convince these guys that it`s possible
> > to do a snap without displacing or tucking ect, because they have never
> > experienced it. and it supports their lack of trimming skills
> > or a poor design ,Sorry Guys!!
> >
> >
> > ,,BTW contrary to popular belief nose heavy airplanes {weight forward }
> > snap better, lands the snap cleaner, and is perfectly consistently ,stays
> > on line way better , { do you have an airplane you have to lead to
> > stop ,,its because it does not recover from the stalled condition its
> > probably tail heavy } a nose heavy { weight forward} set up stops
> > instantly . providing you have the right inputs.
> >
> > In windy weather the 0-0 or sub 1/2 Pos. airplane moves all over the
> > place and is not solid at all. its not directionally stable , because of
> > the tail weight needed to induce the pos inc in the wing.
> > a positive set up will actually weather vein into the wind by itself and
> > you will need opposite rudder to maintain the line sometimes ,,in other
> > words it will self correct in the wind ,,this makes it much easier to fly
> > in windy weather.
> > now ,,,
> > every year designers go back to the drawing boards and play with
> > airfoils, tail moments ,,tail size ,,,hocus pocus ,,ect all in an attempt
> > to fix a trim problem.,, not a design problem.
> >
> > Now to this,,, to correctly trim a model you need three tools,
> >
> > #1 an incidence meter no matter what kind dig. may be better,,
> > #2 honesty without it you will deceive yourself into believing it`s
> > trimmed
> > #3 patience ,,,,I know I just lost some of you But ,
> > there is only one of these three you can do without ,,, it`s the inc.
> > meter,, the other two will guide you if you stay at it till it`s right.
> >
> > Now the Hebert triangulation Method
> > assuming everything else is perfectly straight and aligned correctly ,,,
> > this is a big assumption , but,set your c/g according to the design spec
> > on the drawings for your design as a starting point ,,,if you don`t have
> > a C/G spec contact Nat Penton, he will give you a great formula he has
> > worked up.
> > # 1 set motor at 1/2 deg down ..neg inc.
> > wings at 1/2 pos to start ,,,this is not a hard deck
> > stabs at 1/4 pos because this is about where you will end up.
> > Line up all your control surfaces get them even, because we are going to
> > let the airplane tell us what to do to fix it later
> >
> > #2 fly the airplane trim hands off level flight,, don`t cheat ,,{I know a
> > lot of guys use a little down trim in upright flight to help with upline
> > pulls} it has to be hands off perfect then fly inverted to see if you
> > like the inverted elevator and the airplane feels solid and easy to hold
> > on a line . and then take notes.
> > #3 pull a vertical line see what it does
> > #4 put it straight down see how long it takes to pull out to the canopy
> > #5 do a left rudder knife edge ,see if it`s straight no pull the entire
> > length of the field don`t cheat,,
> > #6do a right rudder knife edge see if it`s straight same as above.
> > This is the triangulation method I use to diagnose all trim problems with
> > any airplane I-MAC to pattern ,,wings are wings.
> >
> > #7 now land and see where the elevator wound up ,,,never mind the stabs
> > right now, we will adjust them later.
> > take notes of what the airplane did in all these three maneuvers, you
> > will see you can triangulate a common input fix, I find it help full to
> > have a buddy to help remember whats happening in the air.
> > Look at the elevator trim and see what it has in it, if we are lucky and
> > your airplane is 10 pounds you are "all over it" and it just may take a
> > little c/g to give a click or two one way or the other.
> > #1 But, if it pulls in the up lines and downline you need more pos inc
> > one turn at a time on the adjuster ,,
> > As an aside ,,,,if you have rear adjusters take them out and put pins and
> > donuts make sure they do not move at all as this will mess with the trim
> > process ,,I find the rear adjusters being a different distance for the
> > wing tube take different amounts of turns to be equal and the wings have
> > to adjust perfectly and lock exactly. no warp in the root., yes it
> > happens and gives you a false reading.
> >
> > #2 if it goes to the belly in left rudder move the c/g forward{ your tail
> > heavy} untill it stops pulling to the belly regardless of the inc.
> > if it goes to the canopy in both knifes #1 will probably fix it
> > but
> > refer to the inverted flight part of you notes and see if you
> > think the elevator was mushy ,hold able but mushy and you might
> > require tail weight. and pos inc. to fix both problems canopy pull
> > downlines and knife edge flight.
> >
> > Because we are on the edge of trim perfection now in all wing loaded, and
> > unloaded ,positions now we can adjust c/g by using the earlier mentioned
> > bullet points for fine tune feeling
> > Remember most of the time one fix will fix 3other things and bring it all
> > together because they are all related, thats why a well trimmed airplane
> > rolls with ease and 4 points with ease. because we are not fighting any
> > adverse trim issues in any axis. or wing load
> >
> > Now do the adjustments and leave the trims on the airplane like they are
> > make another flight your adjustments should Jive with the reverse of what
> > you trimmed on the first flight and make your trims work ,,, if you have
> > to increase the trim you already have in there from the first flight LAND
> > you went the wrong way with the adjustments and make your corrections
> > again
> >
> > < on another side note > for my designs since I know where they should be
> > set ,a quick method is to do the triangulation method this way ,, trim
> > the airplane to fly the down lines,,, leave this trim in and land ,,
> > then adjust the wings to get the trim out and all three Maneuvers are now
> > happy,,,
> >
> > The closer you get to the end, the finer the tuning will need to be, and
> > it can try your patience
> > make sure the tank is centered on the c/g or you will have trim changes
> > during the flight as the tank drains
> >
> > don`t get mad at me if you cannot fix your favorite airplane Just buy a
> > better design ,,,,Mine preferably <G>
> > there is so much more that I could add But I`ll leave it alone for another
> > post.
> > However I would like to add this ,,
> > I agree with Nat that add on T wings are smoke and mirrors However who is
> > going to argue with the word Champion ,,
> > yes it does work ,,somewhat, it reduces the required rudder angle needed
> > to hold knife edges which will in fact reduce mix ,,less rudder less mix
> > ,, A POS setup needs none of this.
> > Hope this helped ,,you may need to read it twice to absorb it all
> > thanks for your interest ,However Brian Clemons is mad at me because I was
> > supposed to be painting his airplane tonight LOL
> > Bryan
> >
> > Chris F. if you Like you can clean this up and include it for a k-factor
> > issue
> >
> >
> >
> >
> >
> >
> >
> >
> > ---- 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
> >> >>>
> >> >>
> >> >> _______________________________________________
> >> >> NSRCA-discussion mailing list
> >> >> NSRCA-discussion at lists.nsrca.org
> >> >> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
> >> > _______________________________________________
> >> > NSRCA-discussion mailing list
> >> > NSRCA-discussion at lists.nsrca.org
> >> > http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
> >>
> >> _______________________________________________
> >> NSRCA-discussion mailing list
> >> NSRCA-discussion at lists.nsrca.org
> >> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
> >>
> >> _______________________________________________
> >> NSRCA-discussion mailing list
> >> NSRCA-discussion at lists.nsrca.org
> >> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
> > _______________________________________________
> > NSRCA-discussion mailing list
> > NSRCA-discussion at lists.nsrca.org
> > http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
>
> _______________________________________________
> NSRCA-discussion mailing list
> NSRCA-discussion at lists.nsrca.org
> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
More information about the NSRCA-discussion
mailing list