SR Fin Spar Cap Layout

[Don Boardman]

Hi Wayne,

My Dad is a really smart guy and he has always said "When all else fails
read the directions" I have to add a caution though ... be careful applying
that rule to the Super Rebel Manual.

Looking at the directions, the top spar caps layout seemed straight forward.
The bottom layout was really lacking and I spent all my time trying to sort
out what should happen in the lower section.

Given the length of the new external cap material and placing the bottom of
the external where it is shown to start and counting the number of rivets
shown above the external cap to locate the top of the internal cap one finds
that the top of the internal is located at first rivet below the middle
hinge rib. Just where the drawing shows it being.

The rivet line showing the rib was so dominant in the drawing I never
noticed the middle hinge on the upgrade drawing. (and my hinge was not
installed on the rear spar at the time) In the drawing the top of the
internal cap was so clearly placed on the rivet below this line and the
number of rivets above the external worked out and SO THATS WHERE I PUT IT.
Silly me!

After your email I compared all the data. Old 2500 and new 3500. The best I
can make out is the length of the raw material for the NEW EXTERNAL CAP is
"two rivets" short if MAM wanted to have the internal extend above the rib
using their drawing and also ignoring the rib's rivet line on the drawing
etc. etc.. So the top of my internal cap may be two rivets short. UNLESS THE
INTERNAL WAS ACTUALLY SUPPOSED TO END ON THE RIVET AS SHOWN IN THE DRAWING
????????????

I did ask myself why MAM was not choosing to pick up the rib but figured
they where the engineers and must figure it was not needed. And I was
surprised that the raw stock for the internal cap was some 100 mm too long.
???????????

Brian was not in this afternoon. I will call him in the morning and see what
he says. My gut feeling is that extending the internal cap two rivets worth
to pick up the rib and match the top of the U channel doubler is not
structurally significant. It looked to me that you increased the distance of
the internal cap even further by three or so rivets. Sure can't hurt.

I'LL LET EVERYONE KNOW WHAT BRIAN SAY IS THE REAL INTENT OF THE DRAWING
STAY TOONED!

If I need to replace the internal cap it will not be the end of the world as
all is still at #40's. Just more time reshaping raw stock and drilling a
thousand more holes ^%$*^$(*^(*%*&$*^^()(*^*%*&$%.


Wayne thanks for you observations.
No matter how much hassle it may be, one always wants to remember ... the
job must be done right!

Don Boardman
& Partner
Randy Bowers
SR130 Rome, NY






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