Rudder counterbalance ?

Grow Pattern pattern4u at comcast.net
Sat Apr 30 13:18:06 AKDT 2005 

Keith,
           I don't really understand the first part of your question. Did 
you mean horn in the first sentence? It is a simple Mylar hinge with a 
bevel. Just like a regular rudder.

I fitted a commercial rudder horn bolt which left the horn points slightly 
behind the hinge line. I set my servo arm holes so that the "non pulling" 
wire stays reasonably taught.

Did I answer it?

Eric.


----- Original Message ----- 
From: "Keith Black" <tkeithb at comcast.net>
To: <discussion at nsrca.org>
Sent: Saturday, April 30, 2005 9:46 AM
Subject: Re: Rudder counterbalance ?


> Eric, where were the hinge points on your original rudder after installing
> the new leading edge? Were they exactly over the hinge line, slightly 
> behind
> or slightly in front of the hinge line?  Also, did you use any offset on
> your servo control arm?
>
> Thanks,
> Keith Black
>
> ----- Original Message ----- 
> From: "Grow Pattern" <pattern4u at comcast.net>
> To: <discussion at nsrca.org>
> Sent: Friday, April 29, 2005 11:43 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
>> >> >>
>> >> >>
>> >> >>
>> >> >> =================================================
>> >> >> To access the email archives for this list, go to
>> >> >> http://lists.f3a.us/pipermail/nsrca-discussion/
>> >> >> To be removed from this list, go to
>> >> > http://www.nsrca.org/discussionA.htm
>> >> >> and follow the instructions.
>> >> >>
>> >> >> List members email returned for mailbox full will be removed from
> the
>> >> > list.
>> >> >>
>> >> >>
>> >> >
>> >> >
>> >> > =================================================
>> >> > To access the email archives for this list, go to
>> >> > http://lists.f3a.us/pipermail/nsrca-discussion/
>> >> > To be removed from this list, go to
>> >> > http://www.nsrca.org/discussionA.htm
>> >> > and follow the instructions.
>> >> >
>> >> > List members email returned for mailbox full will be removed from 
>> >> > the
>> >> > list.
>> >> >
>> >> > ================To access the email archives for this list, go to
>> >> > http://lists.f3a.us/pipermail/nsrca-discussion/
>> >> > To be removed from this list, go to
>> >> > http://www.nsrca.org/discussionA.htm
>> >> > and follow the instructions.
>> >> >
>> >> > List members email returned for mailbox full will be removed from 
>> >> > the
>> >> > list.
>> >> >
>> >> >
>> >> >
>> >> > =================================================
>> >> > To access the email archives for this list, go to
>> >> > http://lists.f3a.us/pipermail/nsrca-discussion/
>> >> > To be removed from this list, go to
>> >> > http://www.nsrca.org/discussionA.htm
>> >> > and follow the instructions.
>> >> >
>> >> > List members email returned for mailbox full will be removed from 
>> >> > the
>> >> > list.
>> >> >
>> >>
>> >> =================================================
>> >> To access the email archives for this list, go to
>> >> http://lists.f3a.us/pipermail/nsrca-discussion/
>> >> To be removed from this list, go to
> http://www.nsrca.org/discussionA.htm
>> >> and follow the instructions.
>> >>
>> >> List members email returned for mailbox full will be removed from the
>> > list.
>> >>
>> >>
>> >
>> >
>> > =================================================
>> > To access the email archives for this list, go to
>> > http://lists.f3a.us/pipermail/nsrca-discussion/
>> > To be removed from this list, go to 
>> > http://www.nsrca.org/discussionA.htm
>> > and follow the instructions.
>> >
>> > List members email returned for mailbox full will be removed from the
>> > list.
>> >
>>
>> =================================================
>> To access the email archives for this list, go to
>> http://lists.f3a.us/pipermail/nsrca-discussion/
>> To be removed from this list, go to http://www.nsrca.org/discussionA.htm
>> and follow the instructions.
>>
>> List members email returned for mailbox full will be removed from the
> list.
>>
>
> =================================================
> To access the email archives for this list, go to
> http://lists.f3a.us/pipermail/nsrca-discussion/
> To be removed from this list, go to http://www.nsrca.org/discussionA.htm
> and follow the instructions.
>
> List members email returned for mailbox full will be removed from the 
> list.
> 

=================================================
To access the email archives for this list, go to
http://lists.f3a.us/pipermail/nsrca-discussion/
To be removed from this list, go to http://www.nsrca.org/discussionA.htm
and follow the instructions.

List members email returned for mailbox full will be removed from the list.

More information about the NSRCA-discussion mailing list