The Murphy Builders Site

-----
To: <rebel-builders@dcsol.com>
Sent: Friday, February 24, 2006 9:22 AM
Subject: Re: [rebel-builders] Rebel Elevator/ web log


Hi Brian!

From reading the list I learned that it is not necessary to beef-up the
rudder ---- although I did, I made pie-doublers flush riveted under the
skin on the horn end and the full mod on the tip end, as. I made a new more
rounded rudder tip with tail light - it came out a bit heavy for my taste
and I still have to check with MAM if it is accptable.
My weblog with pics can be found at
http://www.mykitlog.com/users/index.php ... project=33 if
anyone is interested....

gx from the Alps
Dieter
778R
PS
glad MAM bashing has stopped and to read all the support mails. From my
work
as an animal-doc I know that one angry bull does more harm than hundred
satisfied cows ;-))

----- Original Message -----
From: "Brian Breathnach" <breathnach@shaw.ca>
To: <rebel-builders@dcsol.com>
Sent: Thursday, February 23, 2006 5:56 AM
Subject: [rebel-builders] Rebel Elevator

Ahoy all!

Just finished the elevator mod to prevent skin flexing/cracking at the
outer end of the spar as per the photos in the archives.

Question. Is there a valid reason, or need, to apply the same mod to the
Rudder Horn? Or is it a waste of time to do it because there is no lead
weight in that horn?

Thanx all

Brian R779



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Hi Dieter

It sure is difficult to do any mod that doesn't add more weight than you
expected. If you are concerned, I'd suggest adding a counterweight
forward of the rudder hinge line roughly equivalent to what you added
behind the hinge line. More precisely I'd add the equivalent moment of
inertia such that the weight times arm of each side is about equal. As
always MAM is your best source of advice on this. If you are using a
heavy engine, at least you are adding the weight to right place ;)
Ken

DieterOberbichler wrote:

-----
To: <rebel-builders@dcsol.com>
Sent: Friday, February 24, 2006 9:22 AM
Subject: Re: [rebel-builders] Rebel Elevator/ web log


Hi Brian!

From reading the list I learned that it is not necessary to beef-up the
rudder ---- although I did, I made pie-doublers flush riveted under the
skin on the horn end and the full mod on the tip end, as. I made a new more
rounded rudder tip with tail light - it came out a bit heavy for my taste
and I still have to check with MAM if it is accptable.
My weblog with pics can be found at
http://www.mykitlog.com/users/index.php ... project=33 if
anyone is interested....

gx from the Alps
Dieter
778R
PS
glad MAM bashing has stopped and to read all the support mails. From my
work
as an animal-doc I know that one angry bull does more harm than hundred
satisfied cows ;-))

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Hi there Dieter,

Thank you for the feed back and looks like I will also beef up the rudder at
the top (horn end) since now is the time --during the build-- to do it. I
note from your email below that you did "the full mod on the tip end."
Does
this mean that you did the pie duoubler and bracket mod on the rudder end
closest to the elevators??

You are right about the MAM bashing. The bulls thrashed the china shop once
again. Seems to happen every so often--full moon maybe

Cheers

Brian
Whereabouts in the Alps Dieter?




----- Original Message -----
From: "DieterOberbichler" <d.oberbichler@tirol.com>
To: <rebel-builders@dcsol.com>
Sent: Friday, February 24, 2006 10:26 PM
Subject: Fw: [rebel-builders] Rebel Elevator/ web log

-----
To: <rebel-builders@dcsol.com>
Sent: Friday, February 24, 2006 9:22 AM
Subject: Re: [rebel-builders] Rebel Elevator/ web log


Hi Brian!

From reading the list I learned that it is not necessary to beef-up the
rudder ---- although I did, I made pie-doublers flush riveted under the
skin on the horn end and the full mod on the tip end, as. I made a new
more
rounded rudder tip with tail light - it came out a bit heavy for my taste
and I still have to check with MAM if it is accptable.
My weblog with pics can be found at
http://www.mykitlog.com/users/index.php ... project=33 if
anyone is interested....

gx from the Alps
Dieter
778R
PS
glad MAM bashing has stopped and to read all the support mails. From my
work
as an animal-doc I know that one angry bull does more harm than hundred
satisfied cows ;-))

----- Original Message -----
From: "Brian Breathnach" <breathnach@shaw.ca>
To: <rebel-builders@dcsol.com>
Sent: Thursday, February 23, 2006 5:56 AM
Subject: [rebel-builders] Rebel Elevator

Ahoy all!

Just finished the elevator mod to prevent skin flexing/cracking at the
outer end of the spar as per the photos in the archives.

Question. Is there a valid reason, or need, to apply the same mod to the
Rudder Horn? Or is it a waste of time to do it because there is no lead
weight in that horn?

Thanx all

Brian R779

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Thanks for the advice Ken!
WILCO
I want to leave a small compartment in the nose of the tip where I can add
some counterweight, if neccessary when balancing the rudder and an AME will
definetly have a look at it.
As I am would like to go with an 0320 and will not cut back the firewall, I
try to add as much weight to the tail as possible ;-))

Dieter
778R
----- Original Message -----
From: "Ken" <klehman@albedo.net>
To: <rebel-builders@dcsol.com>
Sent: Saturday, February 25, 2006 2:32 PM
Subject: Re: Fw: [rebel-builders] Rebel Elevator/ web log

Hi Dieter

It sure is difficult to do any mod that doesn't add more weight than you
expected. If you are concerned, I'd suggest adding a counterweight
forward of the rudder hinge line roughly equivalent to what you added
behind the hinge line. More precisely I'd add the equivalent moment of
inertia such that the weight times arm of each side is about equal. As
always MAM is your best source of advice on this. If you are using a
heavy engine, at least you are adding the weight to right place ;)
Ken

DieterOberbichler wrote:

-----
To: <rebel-builders@dcsol.com>
Sent: Friday, February 24, 2006 9:22 AM
Subject: Re: [rebel-builders] Rebel Elevator/ web log


Hi Brian!

From reading the list I learned that it is not necessary to beef-up the
rudder ---- although I did, I made pie-doublers flush riveted under the
skin on the horn end and the full mod on the tip end, as. I made a new
more
rounded rudder tip with tail light - it came out a bit heavy for my taste
and I still have to check with MAM if it is accptable.
My weblog with pics can be found at
http://www.mykitlog.com/users/index.php ... project=33 if
anyone is interested....

gx from the Alps
Dieter
778R
PS
glad MAM bashing has stopped and to read all the support mails. From my
work
as an animal-doc I know that one angry bull does more harm than hundred
satisfied cows ;-))

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Hi Brian!

I thought the additional metal in the tail won't hurt, but I think I have to
stop to "add a doubler here and a doubler there" otherwise I will end up
with a lame duck..
and I always try to keep in mind that reinforcing one part might introduce
or transfer stress to some other part....
It is not that bad ;-)
My mods on the tail:
top end on rudder: pie-piece snugged under
skin and a rib doubler + bracket (overkill) - would only copy if any
modifications to rudder
but I guess it is very important that the rudder tip is really stiff and
that there is no flex on the horn end at all - even more important on
elevators! (thanks Bob P.for pointing this out) I've been watching the
vibrations of the horn ends in the C150 of our Flight School during "high
speed cruise"- scary! with the full length horns of the Rebel you definetly
don't want any oscillations due to flex in the tips - I better shut up as I
am no engineer...

: on the other/bottom end I only made pie doublers
under the rudder skin- dont ask why... is not necessary at all,

: on the outboard elevators I made the top and bottom
pie doubler, rib doubler and a small bracket, (crdits to Wayne)
didn't start with elevator tips yet, if I use MAMs
then I will add some layers of fiberglass or maybe I order Dave Fifes tips
or I start again with messy foam and
fiberglass work... no mods on the inboard side of elevators!
: on left elevator I made a doubler to be put over the
cutout for the trim servo and I mounted the servo-plate with nutplates
: on trim tab - small doubler under trim horn and a
doubler for the trim spar because I marred the inside of the angled spar
when drilling the skin-
STUPID-( so that is no mod -but a fix...)

enough for now

happy deburring
Dieter
778R

We live in TIROL N47