The Murphy Builders Site

Hello All,

Don Boardman here. New Super Rebel builder #130.
In applying the skin on the Elevator, working the skin from the spar reward
toward the trailing edge I am finding that the bend at the trailing edge
should be slightly sharper. As I drill and cleco the skin down moving to the
rear tips of the ribs it will take more than normal force to bring the skin
to the rib. The skin will "bulge" around the area of the rivet line for the
last couple of rivets.

I am ready to rework the trailing edge to reduce the radius of the bend. Any
feedback?

Thanks,
Don Boardman
Rome, NY
Super Rebel #130

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We have Elite 583. The SR & Elite are built quite similarly and indeed we
came across
the same issues on the rudder & elevator skins. We found that if the angle of
the skin
is closed up it will fit better to the ribs and come out smoother. I did this
by
carefully squeezing the skin at the trailing edge by hand. With this
technique the
surface is reasonably free of undulations.

Dave,

My conclusion also. You indicate you squeezed the skin's trailing edge by
hand. Literally? I plan to use vice grips I have with two and four inch wide
jaws. The edge on the elevator is 11 ft long I am a little concerned about
keeping it true. I am reasonably good with sheet metal. I built a CH701, but
would appreciate any tips.

Thanks,
Don
SR130




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I've had to do this in the past for another plane I built.
Use 2x6" x 8ft lumber that is hinged together (using common home door
hinges); space about 1 hinge every 2ft. This assembly is used to 'squeeze'
the trailing edge assembly. However, before you squeeze it, put a long
wooden dowel in the entire trailing edge, using the correct diameter. This
will give you a nice, uniform bend.
However, first check with Murphy technical to make sure you are not changing
the shape of the trailing edge improperly. I understand that in some cases
a sharp leading edge can lead to flutter conditions.

Gary B

----- Original Message -----
From: "Don Boardman" <DBoardm3@twcny.rr.com>
To: "(Murphy Rebel Builders List)" <murphy-rebel@dcsol.com>
Sent: Tuesday, September 12, 2000 7:49 PM
Subject: Re: Super Rebel Elevator Trailing Edge

We have Elite 583. The SR & Elite are built quite similarly and indeed

we

came across
the same issues on the rudder & elevator skins. We found that if the

angle of

the skin
is closed up it will fit better to the ribs and come out smoother. I

did this

by
carefully squeezing the skin at the trailing edge by hand. With this
technique the
surface is reasonably free of undulations.

Dave,

My conclusion also. You indicate you squeezed the skin's trailing edge by
hand. Literally? I plan to use vice grips I have with two and four inch

wide

jaws. The edge on the elevator is 11 ft long I am a little concerned about
keeping it true. I am reasonably good with sheet metal. I built a CH701,

but

would appreciate any tips.

Thanks,
Don
SR130

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Don

We have Elite 583. The SR & Elite are built quite similarly and indeed we came across
the same issues on the rudder & elevator skins. We found that if the angle of the skin
is closed up it will fit better to the ribs and come out smoother. I did this by
carefully squeezing the skin at the trailing edge by hand. With this technique the
surface is reasonably free of undulations.

While you are doing this I'll offer another suggestion and that is that you make sure the
edge flanges of the ribs are perfectly parallel to the skin (in other words perpendicular
to the face of the ribs), this will yield a more flat surface on the elelvator skin as it
is pulled toward the ribs. I would suggest using a long straight edge laid across a
number of the ribs as a reference. Tweak the flanges until they are parallel to the
straightedge and the ribs will not pull the skin in waves.

Let us know how it works out,

Dave R

Don Boardman wrote:

Hello All,

Don Boardman here. New Super Rebel builder #130.
In applying the skin on the Elevator, working the skin from the spar reward
toward the trailing edge I am finding that the bend at the trailing edge
should be slightly sharper. As I drill and cleco the skin down moving to the
rear tips of the ribs it will take more than normal force to bring the skin
to the rib. The skin will "bulge" around the area of the rivet line for the
last couple of rivets.

I am ready to rework the trailing edge to reduce the radius of the bend. Any
feedback?

Thanks,
Don Boardman
Rome, NY
Super Rebel #130

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--
David A. Ricker P. Eng.
DARTEC Engineering Inc.
Fall River, Nova Scotia
Canada

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Don

All I did to massage the trailing edge was carefully grip the it with my hands and
squeeze and it isn't like I have the hands of a gorilla either! I just worked along the
edge from side to side and squeezed until I felt the skin yield some. I was careful to
not go too much at once. It really didn't take much and I didn't wind up with any
waves. Oh, the skin on the Elite elevator is either .016 or .020" where the SR may be
thicker??

I would be careful about using vise gip clamps since they have no "give" at the edges and
could cause localised dimples or waves. You might want to follow the suggestion of
another poster (don't recall the name, sorry) and rig a jig to do a broad width at once
but be careful that you don't get pressure where you don't want it like at the end
points. Make shift bending jigs often don't act as you would expect, I often bend thin
guage steel (ie. car body metal) with a couple pieces of angle iron supported by a vise
and clamps and it is challanging to get an even bend across the width of the part, the
edges bend OK but the centre can give difficulty.

Let me know if I can be of more help on this,

Dave R.



Don Boardman wrote:

We have Elite 583. The SR & Elite are built quite similarly and indeed we
came across
the same issues on the rudder & elevator skins. We found that if the angle of
the skin
is closed up it will fit better to the ribs and come out smoother. I did this
by
carefully squeezing the skin at the trailing edge by hand. With this
technique the
surface is reasonably free of undulations.

Dave,

My conclusion also. You indicate you squeezed the skin's trailing edge by
hand. Literally? I plan to use vice grips I have with two and four inch wide
jaws. The edge on the elevator is 11 ft long I am a little concerned about
keeping it true. I am reasonably good with sheet metal. I built a CH701, but
would appreciate any tips.

Thanks,
Don
SR130


*-----------------------------------------------------------------------------------*
The Murphy Rebel Builders List is for the discussion
between builders and owners of Murphy Rebel aircraft.
Archives located at:
http://www.dcsol.com/murphy-rebel/lists/default.htm
*-----------------------------------------------------------------------------------*

*-----------------------------------------------------------------------------------*
The Murphy Rebel Builders List is for the discussion
between builders and owners of Murphy Rebel aircraft.
Archives located at:
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*-----------------------------------------------------------------------------------*




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