After
removing the molding edges from the plexi, a rough fit is required on the frame. We fit our
canopy in July when the temperature was around 90-95 degrees. We tried to
crack the leftover pieces and were unable to - working with plexi on a hot day
is definitely
a good idea.
From
this point on, there are a series of frightening cuts to get it down to size.
A
number of the cuts (this is the rear piece) are quite substantial.
Before
finishing for the day, there is a lot of cleanup of plexi dust, and you end up
with a few pounds of useless plexi.
Getting
it to fit right means someone has to get inside and check the fit against the
upper bow of the slider frame.
After
seemingly 20-30 cuts along the front, it begins to sit down nicely and match the
curve of the skin. At this point it doesn't have to be perfect as the
canopy is still in one piece. After splitting, a closer fit can be made.
To
split the canopy, we taped it in place after quadruple checking the alignment.
Tape
off the plastic, leaving a small gap where you want to cut....
Hold
your breath and slice it into two pieces (if this sounds a bit melodramatic,
remember that it costs about $1200 if you screw it up).
Successful
split!
Now
sit inside and try to look cool.
While
we were getting our rear bow fixed, we had handles installed on the roll
bar. They were made from 3/8" 4130 solid stock.
Lots
of SLOW drilling and cleco-ing later, the top is attached to the slider.
This was very nerve-wracking. You had to lean over your $1K canopy and
drill slowly through the plexi without tilting or moving the drill. Of
course you also need to be careful not to let the hole enlargen when you hit the
steel. After drilling, then install a cleco without dropping it on the
plexi.
The
side skirts take a bit of finesse. We probably spent more time on these
than any single piece of the canopy. It is a fairly tough thing to get
right as you have to fit two curves (the skin and the canopy) to each other and
keep a number of dimensions to pretty tight tolerances.
We
thought it looked pretty good at this point. This is the underlying
support skin and it seemed to match the longeron/skin curve perfectly.
After
too many hours of fitting/adjustment/etc, we opted for the brute force
approach. On the inside of the canopy, we fabricated a "control"
strip. By pulling up or pushing down on each tab (and then drilling in
place to the steel rod), we were able to set the inboard/outboard angle of the
side skirts perfectly. Yes, this will be visible when sitting in the
plane, but it provides a perfect fit (and extra support during cruise) for the
side skirts.
The
rear skirts were tough until we realized that two people, pulling as hard as you
dare, can get the compound shape into the aluminum.
The
final fit is a little better than this picture shows. By putting a slight
bend in the upper piece, and installing the fairing between the pieces, we were able to get a good
fit all around.
