Today's Message Index:
----------------------
1. 07:05 AM - Heavy Wings on RV-8 (Speedy11@aol.com)
2. 07:29 AM - Re: Heavy Wings on RV-8 (Tracy Crook)
3. 07:58 AM - Re: Heavy Wings on RV-8 (Carl Froehlich)
4. 03:31 PM - Re: Heavy Wings on RV-8 (Dan Bergeron)
5. 06:02 PM - Re: Heavy Wings on RV-8 (James Baldwin)
Message 1
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Subject: | Heavy Wings on RV-8 |
Has anybody out there done something other than squeezing the trailing edge
of the light wing in order to correct a heavy wing problem? Has anyone
discovered an aerodynamic cause for a heavy wing?
I'm stumped.
Stan Sutterfield
Daytona Beach
Message 2
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Subject: | Re: Heavy Wings on RV-8 |
I was confused for awhile too. I spent days getting the wings perfectly
matched for AOA before drilling the aft spar and still had a heavy left
wing. A minor squeezing of the right aileron trailing edge didn't help
enough. A slight adjustment of both flaps in the appropriate (opposite)
directions was effective. The change was not enough to notice any visual
misalignment of flap trailing edges with the ailerons As always, YMMV
depending on the cause of the heavy wing.
Tracy Crook
On Thu, Dec 31, 2009 at 10:04 AM, <Speedy11@aol.com> wrote:
> Has anybody out there done something other than squeezing the trailing
> edge of the light wing in order to correct a heavy wing problem? Has anyone
> discovered an aerodynamic cause for a heavy wing?
> I'm stumped.
> Stan Sutterfield
> Daytona Beach
>
> *
>
> *
>
>
Message 3
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Subject: | Heavy Wings on RV-8 |
I worked this problem on three RV-8s, including my 8A. What I learned was
that control surface rigging on an RV is not a trivial exercise. I also
learned that the "squeezing the trailing edge of the light wing" is the
absolute last thing to do, and it has the least effect. In other words,
this should be considered the final "fine tuning tweak".
Here is a short list of common areas to check:
1. Ignore the alignment of the aileron to flap or aileron to wing tip
trailing edge. Use the templates provided by Van's to define the "ailerons
in trail position" (if you don't have the templates use a straight edge and
ruler). Once you lock one aileron in the trail position, then adjust the
aileron linkage to put the opposite aileron in the trial position.
2. Measure the aileron height (as compared to the wing top or bottom
skin) at both inboard and outboard hinges. Another check is to measure the
gap between the wing top skin trailing edge and the forward top rivet line
on the aileron with the aileron locked in the trailing position. Of all the
rigging problems I've seen, this is the most common. What you may find is
one end of one aileron is lower/higher or more fore/aft than the other end.
This places more aileron surface in the airstream above/below one aileron
than the other - causing the asymmetric lift even though the aileron are
both in the trail position. Two ways to fix this:
a. Call Van's and order a couple of "no hole" aileron hinge brackets.
The hinge brackets Van's sells are pre-drilled. Van's sells no hole
brackets so that you can drill the bolt hole off center - thus placing the
aileron in the correct position.
b. Take the current bracket that needs adjustment and make the bracket
to wing bolt holes into slots (in the direction you need to go) so that the
bracket itself can move up/down. This works only in the up/down direction
however. The no hole brackets allow for adjustment in both the up/down and
fore/aft direction.
3. Once you get the ailerons right, then check for flap and wing tip
alignment. Again with the ailerons locked in the trail position, adjust
each flap trailing edge to align with the aileron when the flap is in the
full up position. This may require you to reposition the fuselage flap
stop. Considering the moment arm on the wingtips, even a small misalignment
can create a roll tendency. During construction the wingtip trailing edge
alignment is possible as you have some control on mounting (a good reason to
delay wingtip mounting until after you complete the above steps on rigging).
If the wingtip is already mounted, you can still fix the trailing edge by
cutting along the trailing edge aft seam to separate the aft wingtip
top/bottom halves. Once separated they can be adjusted to align with the
aileron trailing edge, then glassed back together.
Once you do all of this, fly the airplane and make minor adjustments in the
left/right aileron push tubes as needed. The acid test to tell you if you
are done or not is if you have no change in roll trim with speed.
Carl Froehlich
RV-8A (525 hrs)
RV-10 (systems install)
From: owner-rv8-list-server@matronics.com
[mailto:owner-rv8-list-server@matronics.com] On Behalf Of Speedy11@aol.com
Sent: Thursday, December 31, 2009 10:05 AM
Subject: RV8-List: Heavy Wings on RV-8
Has anybody out there done something other than squeezing the trailing edge
of the light wing in order to correct a heavy wing problem? Has anyone
discovered an aerodynamic cause for a heavy wing?
I'm stumped.
Stan Sutterfield
Daytona Beach
Message 4
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Subject: | Re: Heavy Wings on RV-8 |
Stan:
I had the same frustrating issue with my RV-7A, i.e., a heavy left wing. I
checked everything and made all sorts of minor adjustments to aileron and
flap positions. Nothing seemed to work. No, I never did squeeze an
aileron; and no my wife in the right seat didn't work either.
What I did eventually notice was a very slight difference in the upper
surface, spanwise curvature of the wings, relative to each other, in the
vicinity of the aftmost line of rivets in the wing itself. Either there is
a very slight difference in the positioning of the pre-punched holes, in th
e
flap brace for example, or the parts themselves are slightly different in
size. If you look at mine very carefully you can see that the left wing ha
s
a bit more camber (more like an elongated bump) in that area than the right
wing, and you can feel it with your fingers.
My friend and mentor, three-time repeat offender Fred Stucklen, suggested
what turned out to be the perfect solution: Avery Tools sells a "rudder
trim tab," part #9883. It's nothing more than a solid piece of plastic,
about 5" long, 1.5" from front to back and tapered from a near knife edge i
n
the front to .25" in the rear. I bonded it with proseal to the underside o
f
the outboard trailing edge of the right aileron, just inboard from the
wingtip. It forces the right aileron up ever so slightly; honestly if I
look at the ailerons in flight, I can't see the difference. Problem solved
for $13.50 and a bit of proseal.
What a magnificent flying machine!
Dan Bergeron
RV-7A, N307TB
74 hours since first flight
on 8/4/09 at 7B2 (Northampton Airport, MA)
On Thu, Dec 31, 2009 at 10:56 AM, Carl Froehlich <carl.froehlich@verizon.ne
t
> wrote:
> I worked this problem on three RV-8s, including my 8A. What I learned
> was that control surface rigging on an RV is not a trivial exercise. I a
lso
> learned that the =93squeezing the trailing edge of the light wing=94 is t
he
> absolute last thing to do, and it has the least effect. In other words,
> this should be considered the final =93fine tuning tweak=94.
>
>
> Here is a short list of common areas to check:
>
> 1. Ignore the alignment of the aileron to flap or aileron to wing ti
p
> trailing edge. Use the templates provided by Van=92s to define the =93ai
lerons
> in trail position=94 (if you don=92t have the templates use a straight ed
ge and
> ruler). Once you lock one aileron in the trail position, then adjust the
> aileron linkage to put the opposite aileron in the trial position.
>
> 2. Measure the aileron height (as compared to the wing top or bottom
> skin) at both inboard and outboard hinges. Another check is to measure t
he
> gap between the wing top skin trailing edge and the forward top rivet lin
e
> on the aileron with the aileron locked in the trailing position. Of all
the
> rigging problems I=92ve seen, this is the most common. What you may find
is
> one end of one aileron is lower/higher or more fore/aft than the other en
d.
> This places more aileron surface in the airstream above/below one aileron
> than the other ' causing the asymmetric lift even though the aileron ar
e
> both in the trail position. Two ways to fix this:
>
> a. Call Van=92s and order a couple of =93no hole=94 aileron hinge
> brackets. The hinge brackets Van=92s sells are pre-drilled. Van=92s sel
ls no
> hole brackets so that you can drill the bolt hole off center ' thus pla
cing
> the aileron in the correct position.
>
> b. Take the current bracket that needs adjustment and make the
> bracket to wing bolt holes into slots (in the direction you need to go) s
o
> that the bracket itself can move up/down. This works only in the up/down
> direction however. The no hole brackets allow for adjustment in both the
> up/down and fore/aft direction.
>
> 3. Once you get the ailerons right, then check for flap and wing tip
> alignment. Again with the ailerons locked in the trail position, adjust
> each flap trailing edge to align with the aileron when the flap is in the
> full up position. This may require you to reposition the fuselage flap
> stop. Considering the moment arm on the wingtips, even a small misalignm
ent
> can create a roll tendency. During construction the wingtip trailing edg
e
> alignment is possible as you have some control on mounting (a good reason
to
> delay wingtip mounting until after you complete the above steps on
> rigging). If the wingtip is already mounted, you can still fix the trail
ing
> edge by cutting along the trailing edge aft seam to separate the aft wing
tip
> top/bottom halves. Once separated they can be adjusted to align with the
> aileron trailing edge, then glassed back together.
>
>
> Once you do all of this, fly the airplane and make minor adjustments in t
he
> left/right aileron push tubes as needed. The acid test to tell you if yo
u
> are done or not is if you have no change in roll trim with speed.
>
>
> Carl Froehlich
>
> RV-8A (525 hrs)
>
> RV-10 (systems install)
>
>
> *From:* owner-rv8-list-server@matronics.com [mailto:
> owner-rv8-list-server@matronics.com] *On Behalf Of *Speedy11@aol.com
> *Sent:* Thursday, December 31, 2009 10:05 AM
> *To:* rv8-list@matronics.com
> *Subject:* RV8-List: Heavy Wings on RV-8
>
>
> Has anybody out there done something other than squeezing the trailing ed
ge
> of the light wing in order to correct a heavy wing problem? Has anyone
> discovered an aerodynamic cause for a heavy wing?
>
> I'm stumped.
>
> Stan Sutterfield
>
> Daytona Beach
>
> * *
>
> * *
>
> **
>
> **
>
> **
>
> **
>
> **
>
> **
>
> **
>
> *www.aeroelectric.com*
>
> *www.buildersbooks.com*
>
> *www.homebuilthelp.com*
>
> *www.howtocrimp.com*
>
> **
>
> *http://www.matronics.com/contribution*
>
> **
>
> **
>
> **
>
> **
>
> **
>
> **
>
> **
>
> **
>
> *http://www.matronics.com/Navigator?RV8-List*
>
> **
>
> **
>
> **
>
> *http://forums.matronics.com*
>
> **
>
> * *
>
===========
===========
===========
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> *
>
>
Message 5
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Subject: | Heavy Wings on RV-8 |
RV Guys,
Many builders of all homebuilts have experienced a heavy wing even when they
have been constructed meticulously. One common reason for many has been
traced to the fiberglass wingtip fairings. A slight mismatch is
particularly pronounced because of the obviously long moment arm. If your
problem can't be solved with a minor differential flap adjustment the
wingtips are the next place to consider. One friend made a dramatic
difference by slitting the trailing edge of one which looked a little off
and re-glassed it in a more favorable position. My RV8 is sensitive but any
wing heaviness is easily adjusted out with the aileron spring loading trim
system installed. I note however it's best if I burn out of the right tank
first. Just FYI. James Baldwin
_____
From: owner-rv8-list-server@matronics.com
[mailto:owner-rv8-list-server@matronics.com] On Behalf Of Tracy Crook
Sent: Thursday, December 31, 2009 7:27 AM
Subject: Re: RV8-List: Heavy Wings on RV-8
I was confused for awhile too. I spent days getting the wings perfectly
matched for AOA before drilling the aft spar and still had a heavy left
wing. A minor squeezing of the right aileron trailing edge didn't help
enough. A slight adjustment of both flaps in the appropriate (opposite)
directions was effective. The change was not enough to notice any visual
misalignment of flap trailing edges with the ailerons As always, YMMV
depending on the cause of the heavy wing.
Tracy Crook
On Thu, Dec 31, 2009 at 10:04 AM, <Speedy11@aol.com> wrote:
Has anybody out there done something other than squeezing the trailing edge
of the light wing in order to correct a heavy wing problem? Has anyone
discovered an aerodynamic cause for a heavy wing?
I'm stumped.
Stan Sutterfield
Daytona Beach
_blank">www.aeroelectric.com
.com" target="_blank">www.buildersbooks.com
="_blank">www.homebuilthelp.com
nk">www.howtocrimp.com
_blank">http://www.matronics.com/contribution
et="_blank">http://www.matronics.com/Navigator?RV8-List
tp://forums.matronics.com
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