[NSRCA-discussion] Joy of Trim
Koenig, Tom
Tom.Koenig at actewagl.com.au
Mon Apr 14 19:43:03 AKDT 2008
Hi all,
Just remember Bryan's three golden rules: # 2 and # 3 are the
secret-don't let the plane fool you!!! It ends up being an endless loop,
each time the errors get smaller, but it can really drive you nuts...but
it is possible.
Tom
#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.
________________________________
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Derek
Koopowitz
Sent: Tuesday, 15 April 2008 12:28 PM
To: 'NSRCA Mailing List'
Subject: Re: [NSRCA-discussion] Joy of Trim
Sorry Nat... I must have blown right by this one! <along with the wind>
We had great weather this past weekend - temps in the high 80's and
little to no wind. I got a chance to finally do some decent trimming
over the weekend (Sunday especially) and I think the plane is just about
trimmed to my liking. I did add nose weight (battery pack) and that has
definitely helped as well.
Mixes:
Downline - down ele to maintain straight line - 2%
KE - both require up ele (5% on one side and 8% on the other) - also
need ail. to maintain KE
I also have a low throttle - ail mix (1%) to counteract a very slight
roll to the left when coming off throttle.
________________________________
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Nat
Penton
Sent: Monday, April 14, 2008 7:15 PM
To: NSRCA Mailing List
Subject: Re: [NSRCA-discussion] Joy of Trim
Derek, are you keeping your mixes secret <G>
----- Original Message -----
From: Nat Penton <mailto:natpenton at centurytel.net>
To: NSRCA Mailing List <mailto:nsrca-discussion at lists.f3a.us>
Sent: Saturday, April 12, 2008 8:26 PM
Subject: Re: [NSRCA-discussion] Joy of Trim
Derek, any good weather yet - what mixes are you using ?
----- Original Message -----
From: Derek Koopowitz <mailto:derekkoopowitz at gmail.com>
To: chad at f3acanada.org ; NSRCA Mailing List
<mailto:nsrca-discussion at lists.f3a.us>
Sent: Thursday, April 10, 2008 11:13 AM
Subject: Re: [NSRCA-discussion] Joy of Trim
That is great news, Chad. I'm glad to hear that the
issues got resolved.
I'm also very close on my setup... my stab is at 0 and
the wings are almost +.5. The plane comes standard without downthrust
and I have since added some to help with the pull to the canopy in the
upline - its almost 100% but not quite. I think I may still be a little
tail heavy and will add some nose weight when I get a day that is calm -
it has been a little breezy here. Overall my plane is flying much
better now as well.
On Thu, Apr 10, 2008 at 8:56 AM, Chad Northeast
<chadnortheast at shaw.ca> wrote:
Guys
A while back I posted this, and have recently got around
to the suggestions. Both Bryan and Nat said that the TL was far too
much negative as the Twister has -2.5 deg molded into the fuse. So away
I went, here is a copy of the email (just below) I sent to them after my
flights to resolve it.
Before last week you could have never convinced me that
you could get a plane neutral in knife edge without giving up
something....well I officially stand corrected :-) They know their
stuff, were right on the money and the Twister goes pretty much anywhere
you point it now without mixing (except a bit on downline but I think I
can get rid of that).
I gotta say thanks to Bryan and Nat for their help, they
were bang on, and I would suggest to anyone that you give their
suggestions and honest try, I bet you are more than happy with the
results!
Chad
Hey guys,
Well finally got out flying, good thing too since I am
off to NY state
again on Monday :-(
So, here is where I was, I broke down and bought an
inclinometer so I
could actually measure the plane directly....since I am
too lazy to do
trig.
Engine, as molded is -2.5 but I was at -3.5, wing +0.8,
stab +0.1.
So I got as much of the down out of it as possible which
leaves me at -1,
I can't do any more without shimming the motor further
out for more
clearance spinner to nose ring. I put the wing back to
+0.5 and left the
stab alone.
First flight today, removed the left rudder KE mix I had
(had none on
right rudder), and downline mix.
- Plane needed a bit of down trim for level, but was
pretty close
- Uplines went to the canopy
- 45 ups inverted pulled over the top fairly hard
- 45 downs upright were pretty decent but still dove a
bit - recall this
was my major beef with previous setup
- knife was pulling to canopy both ways
Second flight - moved CG back as I have felt that it was
too far forward
in general, and I think you would agree if you saw where
it was.
- more down trim
- Uplines became very close
- knife both ways was pretty good, really solid with
right rudder, and
very very close on left (slight belly pitch)...probably
not worth mixing
out
- 45 downs upright were getting better
- downline mix reduced 2% from start
- 45 ups inverted better
Third flight - took out 1/2 turn of incidence, which by
trig should put me
at 0.41+ on the wings
- uplines became perfect, or really close...would need
more flights in
various conditions to nail
- everything else was really close
Fourth flight - decided to adjust stab since I was
carrying a little up
elevator, so I took 1/2 turn out of adjuster which
should being it close
to 0
- this pretty much sealed it
- uplines are as before, very very close
- no KE mix - even in the KE loop at high deflections
its really, really
good
- took another 1% out of my downline mix (I am at 2%,
started at 5%)
- 45 ups inverted are really good, just a slight arc
over the top
- 45 down upright is finally straight.
I need to spend some more time on it to really get a
good feel, but I
think the downthrust was causing a lot of problems to
this plane. I have
never had it in all aspects of flight this close yet. I
am anxious to get
more time on it and see if the changes really stick.
Unfortunately on
Sunday this plane is going to a buddy but I plan on
incorporating all
these changes on the new Twister which is why I wanted
to get it figured
out now :)
Any further comments? CG is probably around 33% of MAC,
but to be exact I
would have to calculate.
Upline snaps are as you say Bryan, on axis with no need
to lead....I was
pretty happy to see that result :)
Chad
> > > From: "Chad Northeast" <chadnortheast at shaw.ca>
> > > To: "NSRCA Mailing List"
<nsrca-discussion at lists.nsrca.org>
> > > 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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