Rudder counterbalance ?

[gorden]

what is a DAMPER from a rc car????? thanks gorden.
----- Original Message ----- 
From: "Grow Pattern" <pattern4u at comcast.net>
To: <discussion at nsrca.org>
Sent: Friday, April 29, 2005 10:43 PM
Subject: Re: Rudder counterbalance ?


> Jim,
>         I had already converted the IMPACT supplied rudder over to a
regular
> Mylar hinge set up because of the side-play in the hinge-pin design
> supplied.
>
> It oscillated with the stick pin hinges at the first switch-on. I "pulled"
> the composite the rudder off and fitted it with a new stern-post and
beveled
> the LE, on the rudder. Then I tried all of the servos previously listed.
>
> I then cut off the IMPACT rudder and fitted the new (red) one as you can
see
> on RCU.
>
> As powerful as our new digital servos are I don't think that they "brake"
> the return swing as well as they initiate the first movement/response.
>
> It is noticeable that the bigger planes use multiple servos with the
> thinking that more power is needed. It is more stopping power that, IMHO,
> the we really need.
>
> I had an 8611 that bounced when used to drive a big old VISION rudder.
After
> fitting a damper from an RC car it performs flawlessly.
>
> Regards,
>
> Eric.
>
>
>
>
> ----- Original Message ----- 
> From: "J.Oddino" <joddino at socal.rr.com>
> To: <discussion at nsrca.org>
> Sent: Friday, April 29, 2005 3:26 PM
> Subject: Re: Rudder counterbalance ?
>
>
> > Eric,
> > What you were experiencing was oscillation of a servomechanism and that
> > could contribute to flutter and flutter could be what is breaking the
> > Impacts but I've never heard anyone say they heard the rudder flutter
> > before
> > the fuse exploded.  I don't think we understand the root cause yet.
> > Right now I'm interested in the servo/rudder oscillation.  I'm wondering
> > if
> > the real solution is completely due to the light weight rudder or/and to
> > an
> > improved hinging system, or did both have the same hinge installation?
> > Can
> > you hang weight on your present rudder and make it oscillate?  It sure
> > would
> > be nice to cure this problem for all time because I've seen it on many
> > planes.  I've never heard of it breaking fuselages before though.
> > Thanks for all of your experimentation.  In the end it is more important
> > than understanding the theory.
> > Jim O
> > ----- Original Message ----- 
> > From: "Grow Pattern" <pattern4u at comcast.net>
> > To: <discussion at nsrca.org>
> > Sent: Thursday, April 28, 2005 8:55 PM
> > Subject: Re: Rudder counterbalance ?
> >
> >
> >> Peter,
> >>             I nearly got to go to bed.! ...Just ran
downstairs...Tripped
> >> over #2 Son who is back from carrier duty - he said we dropped a lot of
> >> "stuff " out there. Planes all came back without ordnance,! No lost
> >> planes....A  bit worried about the local girls however.. it must be
that
> >> uniform thing :-)
> >>
> >> Where was I?...Both supplied IMPACT rudders weigh 3.1 oz each without
> > hinges
> >> or horns
> >>
> >> Replacement rudders weigh 1.3 oz before covering.
> >>
> >> I tried the supplied rudder and five different servos including an 8611
> > and
> >> they all bounced back and forth badly and were potentially
destructively.
> >>
> >> I then cut it off (the old rudder) and fitted a foam balsa replacement.
> >> Tests showed no bounce with any of the servos. [8611, 8411, 8417, 8417
> > with
> >> 8411 gears and the heli 8311 (nylon gears except for output shaft.]
> >>
> >> I did managed to stop the bounce another way. I also tried using a
single
> >> wire as opposed to multi-strand. It did work but once in a while I saw
> >> bad
> >> "hunting" as it located the center.
> >>
> >> These Impacts have polyurethane foam liners about 1.5-mm thick with a
> >> skin
> >> of glass inside that. They are pretty stiff to begin with.
> >>
> >> I did notice that a vertical former at the rear of the canopy area made
a
> >> huge difference in stiffness. Also switching to a four bolt wing
> >> retention
> >> system made the center more rigid.
> >>
> >> I have abused my IMPACT #1 and hope that all the mods keep doing their
> > job.
> >> I still think that the rudder is simply just too heavy and the
> >> spring/stretch in the pull-pull wire combines to oscillate the rudder
> >> just
> >> like PIO.
> >>
> >> Regards,
> >>
> >> Eric.
> >>
> >> ----- Original Message ----- 
> >> From: "Peter Pennisi" <pentagon.systems at bigpond.com>
> >> To: <discussion at nsrca.org>
> >> Sent: Thursday, April 28, 2005 6:19 PM
> >> Subject: RE: Rudder counterbalance ?
> >>
> >>
> >> >
> >> > I am aware of the braces and internal formers. There have been recent
> >> > cases
> >> > of failures with all the supporting structures in place.
> >> >
> >> >
> >> > Eric,
> >> >
> >> > How much do your new rudders weigh typically?
> >> >
> >> >
> >> > Regards,
> >> >
> >> >
> >> > Peter
> >> >
> >> >
> >> > Peter Pennisi
> >> > Pentagon Systems QLD Pty Ltd
> >> > P.O Box 4280
> >> > Eight Mile Plains
> >> > QLD 4113
> >> > Australia
> >> > Phone:    61+0738414234
> >> > Fax:        61+0738414264
> >> > Mobile:   0408007206
> >> > Email: pentagon.systems at bigpond.com
> >> >
> >> > -----Original Message-----
> >> > From: discussion-request at nsrca.org
> >> > [mailto:discussion-request at nsrca.org]
> >> > On
> >> > Behalf Of Atwood, Mark
> >> > Sent: Friday, 29 April 2005 4:56 AM
> >> > To: discussion at nsrca.org
> >> > Subject: RE: Rudder counterbalance ?
> >> >
> >> > Well...I can certainly speak to needing this in the Rev Pro...which
I'm
> >> > guessing isn't a whole lot different than the Impact in construction.
> >> > The fuselage buckled and snapped in half in flight (and yes...it
still
> >> > managed to fly to the ground with relatively little damage).  Added
the
> >> > light (4gm) "Ladder" crutch plate behind the wing and no problems at
> >> > all.
> >> >
> >> > I have a photo of the brace if someone is interested...contact me
> >> > offline.
> >> >
> >> > -Mark
> >> >
> >> > -----Original Message-----
> >> > From: discussion-request at nsrca.org
> >> > [mailto:discussion-request at nsrca.org]
> >> > On Behalf Of Wayne Galligan
> >> > Sent: Thursday, April 28, 2005 2:26 PM
> >> > To: discussion at nsrca.org
> >> > Subject: Re: Rudder counterbalance ?
> >> >
> >> > I have had conversations with a few people that own these airframes
> >> > (Impact)and they along with a few others have strengthened the fuse
in
> >> > two
> >> > ways.  A ladder  type frame in the fuse from the wing t.e back to the
> >> > stab
> >> > area and another put a stiffener(former) at the front of the wing
area
> >> > to
> >> > decrease the possibility of compression of the fuse in this area.  It
> >> > is
> >> > believed that compression of the fuse in this area contributes to a
> >> > wave
> >> > progression all the way back to the tail section.  The tail section
> >> > being
> >> > the smallest and weakest area gets whipped and eventually the fuse
> >> > breaks or
> >> > contributes to tail feather flutters.
> >> >
> >> > From what I've heard....  FWIW
> >> >
> >> > WG
> >> >
> >> >
> >> > ----- Original Message ----- 
> >> > From: "Peter Pennisi" <pentagon.systems at bigpond.com>
> >> > To: <discussion at nsrca.org>
> >> > Sent: Thursday, April 28, 2005 4:29 AM
> >> > Subject: Rudder counterbalance ?
> >> >
> >> >
> >> >>
> >> >>
> >> >> Hi all,
> >> >>
> >> >>
> >> >> Most of you would be aware that a number of Composite ARF "IMPACT"
> >> > have
> >> >> failed from suspected rudder flutter.
> >> >>
> >> >>
> >> >> I raise a couple of questions to this forum;
> >> >>
> >> >>
> >> >> I know that the purposes of counterbalances are to reduce the loads
on
> >> >> servos and linkages in our application but what are the side
effects.
> >> >>
> >> >> Can a rudder counterbalance create undesired torsional stresses on
the
> >> >> fuselage?
> >> >>
> >> >> Can a poorly configured and tensioned pull-pull linkage to the
rudder
> >> > be
> >> >> more susceptible to flutter if the rudder has a counterbalance?
> >> >>
> >> >> What other types of forces are at play with counterbalances?
> >> >>
> >> >> I am just trying to find a reason for the relatively high failure
> >> > rates
> >> >> against this design.
> >> >>
> >> >> It is the same old thing- why are some people having problems and
> >> > others
> >> >> don't. (Similar story to 4-stroke exhaust headers)
> >> >>
> >> >> I will be test flying my model soon so I am obviously concerned.
> >> >>
> >> >> Regards,
> >> >>
> >> >> Peter
> >> >>
> >> >>
> >> >>
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