The Murphy Builders Site

I thought the manual did specify a doubler there. It is certainly
standard to use a doubler on any opening in a stressed skin and that is
a rather large opening. I made the doubler large enough to facilitate
attaching a fairing but later decided to omit the fairing. It seems that
most doublers are 0.032 thick or more but I personally am happy with
.020 or .025 in places that are only protecting against cracking rather
than strength increases.
Ken

On 7/5/2011 7:11 AM, mikeh@dcsol.com wrote:

Hi all,
Does anyone have any comments re the benefits/necessity for a doubler
around the slot in the bottom skin of the wing for the torque tube horn?
All comments appreciated.
Cheers Mike

-----------------------------------------------------------------
List archives located at: https://mail.dcsol.com/login
username "rebel" password "builder"
Unsubscribe: rebel-builders-unsubscribe@dcsol.com
List administrator: mike.davis@dcsol.com
-----------------------------------------------------------------

Hi Mike
I never thought about a doublers until you mention it. In fact I had
trouble finding the area in the manual (that was a long time ago) where it
describes cutting the control horn slot (10.9.10). The slot is riveted very
close to rib. #7 and the rear spar so maybe that was considered suffcent
support for the 1/4 slot. I can find no suggestion of adding a doublers
over this area, but it may be a good idea, sure couldn't hurt.
Charlie E. 802R
----- Original Message -----
From: <mikeh@dcsol.com>
To: <rebel-builders@dcsol.com>
Sent: Tuesday, July 05, 2011 6:11 AM
Subject: [rebel-builders] Doubler on bottom wing skin

Hi all,
Does anyone have any comments re the benefits/necessity for a doubler
around the slot in the bottom skin of the wing for the torque tube horn?
All comments appreciated.
Cheers Mike



-----------------------------------------------------------------
List archives located at: https://mail.dcsol.com/login
username "rebel" password "builder"
Unsubscribe: rebel-builders-unsubscribe@dcsol.com
List administrator: mike.davis@dcsol.com
-----------------------------------------------------------------

-----------------------------------------------------------------
List archives located at: https://mail.dcsol.com/login
username "rebel" password "builder"
Unsubscribe: rebel-builders-unsubscribe@dcsol.com
List administrator: mike.davis@dcsol.com
-----------------------------------------------------------------

I have an .020 doubler on mine that ties into the rib and the rear spar. I'm pretty sure it was in my manual but may have been a suggestion from the rebel rouser newsletter we used to get.
------Original Message------
From: mikeh@dcsol.com
Sender: mike.davis@dcsol.com
To: rebel-builders@dcsol.com
ReplyTo: rebel-builders@dcsol.com
Subject: [rebel-builders] Doubler on bottom wing skin
Sent: Jul 5, 2011 7:11 AM

Hi all,
Does anyone have any comments re the benefits/necessity for a doubler
around the slot in the bottom skin of the wing for the torque tube horn?
All comments appreciated.
Cheers Mike



-----------------------------------------------------------------
List archives located at: https://mail.dcsol.com/login
username "rebel" password "builder"
Unsubscribe: rebel-builders-unsubscribe@dcsol.com
List administrator: mike.davis@dcsol.com
-----------------------------------------------------------------




Sent on the TELUS Mobility network with BlackBerry



-----------------------------------------------------------------
List archives located at: https://mail.dcsol.com/login
username "rebel" password "builder"
Unsubscribe: rebel-builders-unsubscribe@dcsol.com
List administrator: mike.davis@dcsol.com
-----------------------------------------------------------------

FWIW, I added a .025 doubler to each inspection hole on the wing. The weight
gain should be negligible. Looks a bit industrial as I did it after the fact
once the wings were built. I'm sure I came across a diagram in the plans
which depicted the two hole doubler at the strut attach point on the wing. I
believe it ties in the rib and the spar.

Roland
R56



-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of
mikeh@dcsol.com
Sent: Wednesday, July 06, 2011 6:33 AM
To: rebel-builders@dcsol.com
Subject: [rebel-builders] Doubler on bottom wing skin

Hi all,
Thanks for all your comments. There is nothing in my manual about a
doubler. I had seen a couple when I built my wings and, thinking light and
being a bit of a smart arse (and a looong way from flying) when cutting the
slots I drilled a hole in the skin at each end of the proposed slot and,
using a dremel made one thin cut from hole to hole on the side of the slot
next the rib. This allowed me to bend the skin between the holes upwards 90
deg inside the wing forming a stiffening angle on the unsupported side of
the slot. What it didn't do was support the skin at each end of the slot.
I'll will decide whether to add a doubler now to be safe or wait and
see if it cracks and then add the doubler.
Has anyone experienced cracks about these slots? I don't think I've
heard of any.
Hope Oshkosh is good for those involved.
Cheers Mike



-----------------------------------------------------------------
List archives located at: https://mail.dcsol.com/login
username "rebel" password "builder"
Unsubscribe: rebel-builders-unsubscribe@dcsol.com
List administrator: mike.davis@dcsol.com
-----------------------------------------------------------------






-----------------------------------------------------------------
List archives located at: https://mail.dcsol.com/login
username "rebel" password "builder"
Unsubscribe: rebel-builders-unsubscribe@dcsol.com
List administrator: mike.davis@dcsol.com
-----------------------------------------------------------------

Hi Mike,

there is a clear guidance in the Rebel manual about this:

"173. Make a skin doubler from stock material, (i.e. .032") using a 1"
circumference around the torque tube horn opening in the bottom skin,
(W-126)."

You may have a look into Wrays Rebel page on this.
http://wrayt.tripod.com/rebman.html
I myself combined this with the doubler for the inspection holes.


Greetings from Germany
Thomas

Hi all,
Thanks for all your comments. There is nothing in my manual about a
doubler. I had seen a couple when I built my wings and, thinking light and
being a bit of a smart arse (and a looong way from flying) when cutting the
slots I drilled a hole in the skin at each end of the proposed slot and,
using a dremel made one thin cut from hole to hole on the side of the slot
next the rib. This allowed me to bend the skin between the holes upwards 90
deg inside the wing forming a stiffening angle on the unsupported side of
the slot. What it didn't do was support the skin at each end of the slot.
I'll will decide whether to add a doubler now to be safe or wait and
see if it cracks and then add the doubler.
Has anyone experienced cracks about these slots? I don't think I've
heard of any.
Hope Oshkosh is good for those involved.
Cheers Mike



-----------------------------------------------------------------
List archives located at: https://mail.dcsol.com/login
username "rebel" password "builder"
Unsubscribe: rebel-builders-unsubscribe@dcsol.com
List administrator: mike.davis@dcsol.com
-----------------------------------------------------------------

-----------------------------------------------------------------
List archives located at: https://mail.dcsol.com/login
username "rebel" password "builder"
Unsubscribe: rebel-builders-unsubscribe@dcsol.com
List administrator: mike.davis@dcsol.com
-----------------------------------------------------------------