After I got back from lunching with my daughter
in Flower Mound this afternoon, I sized and pinned wooden shims under the
back of each rib to be cut off as shown below. Notice the rib cutting set
up.
This is a close up showing how the vertical blade
is placed up against the rib with a 3/8" balsa back up block to cut the rib
guillotine style. I was careful to keep the blade vertical and up against
the forward face of the rear spar to get a good clean vertical cut on the
rib.
After the ribs and the wide trailing edge were
cut, the elevator was separated from the stab primary structure as shown
below. Notice the wide trailing edge cuts are on an angle because the
elevator tip ribs are going to be inclined with false ribs rather than
straight back.
This picture shows the elevator structure
completely removed from the stab, which is now ready to have its rear
spar installed.
The new rear spar was cut from a 1/4" medium hard
balsa sheet slightly over size in height so as to be trimmed later. An
aluminum angle was elevated on 1/4" blocks at each end and pushed up against
the back of the 1/4" balsa rear spar to maintain straightness and to hold it
in place up against the back of the stab ribs. Pressure was applied to back
of the aluminum angle with wooden blocks pressing on the three steel
squares. The pressure was maintained by clamping the wooden blocks with the
three black Quick Clamps. This can be seen in the picture below. Then the
butt end of each rib was CA'd to front face of the new 1/4" rear spar.
This picture shows the new 1/4" rear spar from
the front side. As you can see, by cutting the ribs off in front of the
original rear spar, the butt end of the ribs make full contact down the new
alternate rear spar.
This last picture shows the installation of the
new 1/4" rear spar from the back side. This has truly been a tedious ordeal,
but I think the results have turned out well. Tomorrow I will tie in the
wide trailing edge with the new rear spar using 1/8" inclined false ribs on
each end....................Tandy
