Comet Sailplane
Project
During the construction of the Sailplane, I have
been using temporary wooden Maple motor mount spacers to make room for the
metal fuel tank behind the McCoy 60 and hold the forward landing gear strut
in place as shown below.
I have now replaced these temporary spaces with
machined aluminum spacers. Even though the aluminum spacers fit perfectly,
they were hard get on and seemed to bind when tightened down on the firewall
because they were slightly tilted. Worse yet, when removed they caused the
1/8" landing gear wire to leave a slight indentation in the firewall. I
checked the depth of the 1/8" groove in the aluminum spacers and they was
precisely 1/8" deep. Something was definitely wrong that I did not
understand.
I sat and looked at the installation for some
time last evening and then it finally came to me what the problem was. The
two .010" metal landing gear straps shown below used to attach the 1/8" wire
to the firewall was causing an .010" standoff from the firewall at the apex
of the bent wire. However, the aluminum spacers were machined so accurately
that when they were tightened down, the slope of the wire was causing
binding and the wire to mash into the edges of the firewall (DUH). The
simple fix was to make two .010" metal back up plates with the same foot
print as the spacers to go between the landing gear wire and firewall so the
wire would remain parallel to the face of the firewall as shown below.
With the .010" back up plates in position, the
aluminum spacers went right on and tightened down smoothly with no binding
or indentation in the firewall as shown below.....................Tandy
