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Feb 3, 2008 1.2 hours - Fit top window
I drilled
out the holes in the top window to 1/8", which is almost exactly the 3.2 mm diameter specified in the kit manual.
I used a plexiglass drill for this step to prevent cracking of the window. A plexiglass drill has the tip ground to
a finer point and the drill cutting edges are flattened to keep them from grabbing the material and starting a crack.
I then checked the window orientation that was the best match with the recess in the top of the fuselage
and taped it in place centered in the recess, which left about 2 mm clearance all around the lip, per the manual.
I drilled a couple of holes through the window
into the rim of the fuselage opening and checked them against the rivets supplied with the kit. I found that the rivets
were actually slightly larger than 1/8" in diameter. I measured the rivet diameter as 0.153", which is just
slightly less than a 5/32" drill (0.156"), so I drilled all the holes out to 5/32", using a plexiglass drill
stop set at 1 cm depth to keep from drilling through the bottom of the rim inside the fuselage. I inserted a rivet temporarily
at each hole as I drilled them, to keep everything aligned as I went.
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| Drill stop |
I found that there are 22 holes pre-drilled in the top window,
but only 20 rivets in the kit, so I will need to obtain two more rivets from the factory. Before requesting the additional
rivets, I will check the holes against the inventory for the windshield and the side door windows.
I also
found that the kit inventory shows that the rivets for the top window and windshield are 4 mm diameter, while the rivets for
the side windows are 3.2 mm diameter. This difference was not noted in the kit manual.
I marked the top window orientation for later installation and marked around the edge of the fuselage rim on the
protective film covering the top surface of the window.
I then removed the window and drilled the holes to 4.5 mm for clearance around the rivets when the window is installed,
relieving any stress on the holes when the rivets are squeezed so that the window will not crack after installation under
the stress of engine vibration and temperature changes.
February 12, 2008 1.5 hours - Prepare
top window for painting
I confirmed that the number of rivets matched the number of mounting holes for the windscreen and side
windows, so I emailed Leon at Pipistrel and requested two more rivets for the top window. Leon immediately mailed me
some additional rivets, which arrived in a few days.
I chamfered the edges of the top window
using a single-edge razor blade as a scraper held at 45 degrees to the surface. Then I sanded the edge all the way around
with #400 emery cloth. I sanded parallel to the edge until I had removed all scratches left perpendicular to the edge
by the saw when the window was cut to its original shape. I also chamfered both sides of each hole slightly with a rotary
cutter.
I peeled the plastic covering away from the edge of the inside surface of the lexan,
exposing the frame edge outline on the outside surface. I held the plastic back from the edge with masking tape, then
applied black plastic (electrical) tape matching the frame outine. I then used some additional masking tape over the
black plastic tape to ensure that the masking would have no gaps to let the spray paint through.
Before the exposed edge is painted, it must be sanded with #1000
paper to remove the shine from the surface so that the paint will adhere. I wasn't able to do this immediately after
completing the masking. This picture was taken a few days later, showing that the plastic tape had pulled away from
the surface. So, when you do this, plan to proceed immediately to the sanding and painting step. I had to remove
the tape and mask it again.
March 22, 2008 2.5 hours - Paint top window and prepare left door window for mounting
I re-masked the top window where the black plastic tape
had pulled away from its original position while it sat idle for several days. I sanded the exposed edge with emery
cloth to remove the gloss from the lexan surface, and then sprayed the edge black with the bumper spray paint provided
in the kit. I applied two light coats of paint as instructed in the kit manual, then set the window aside to dry.
The result is a black perimeter on the inside surface of the lexan matching the shape of the window opening in the top of
the fuselage.
I set the top window aside to
be installed after the other work on the fuselage is completed.
I positioned
the left door window over the frame. The left and right windows are close in shape but not identical. In the standard
kit the left door has ventilation openings drilled in the lower forward corner. The right door has a rectangular cutout
for a sliding panel. In my kit I also specified an option for a second sliding panel in the left door, situation high
enough to be used for aerial photography with a hand-held camera.
I taped the window in position on the frame to achieve an even
gap around the edge. Then I drilled the mounting holes through the lexan into the frame with a 1/8" drill, using
cleco clamps in each hole to keep the window from shifting. I used a drill stop on the drill to ensure that I didn't
drill all the way through the inside of the door frame. Then I marked the edge of the door frame on the outside surface
of the window (actually, on the protective plastic coating) with a fine Sharpie marker.
I removed the clecos and tape and set the window aside.
I then enlarged the holes in the frame slightly with a #29 drill (3.4 mm), because the rivets would not slip through the 1/8"
holes.
Next I enlarged the holes in the window to 5/32" (3.9 mm) for extra clearance around the rivets to
avoid stress on the lexan as the rivet expands on installation. I chamfered the edges of the window and sanded the edge
all the way around with #400 emery cloth. I sanded parallel to the edge until I had removed all scratches left perpendicular
to the edge by the saw when the window was originally cut to shape.
As with the top window, I peeled the plastic covering away from the
edge of the inside surface of the lexan, exposing the frame edge outline on the outside surface. I held the plastic
back from the edge with masking tape, then applied black plastic (electrical) tape matching the frame outline. I then
used some additional masking tape over the black plastic tape to ensure that the masking would have no gaps to let the spray
paint through.
I sanded the exposed lexan surface with emery cloth to remove
all sheen, then sprayed it with two coats of black bumper spray paint.
You can see the rectangular camera window
in the upper portion of the window.
March 23, 2008 2.4 hours - Prepare right door window
for installation
I prepared the right door window for installation in the same way as the left. This window came
right up to the edge of the door recess in a few places, so I filed those edges back slightly to get an even gap of approximately
2 mm all the way around. I set both windows aside for the paint to dry for a full day before
installing them in the door frames.
March 24, 2008 3.5 hours - Install windows in doors
I applied a small (approximately 1/8") bead of black silicone
along the center of the window recess in the right door, then set the window in place carefully. I left all the masking
in place to catch any silicone squeezed out of the joint. Then I inserted clecos in all the holes, securing the window
in place. The clecos also pulled the window against the door, squeezing the silicone into the joint. The 1/8"
bead worked out pretty well, with only a very minor amount of excess silicone appearing at the edges of the joint. Then I removed the clecos one by one, pulled the plastic covering back
from the edge and held it with masking tape, inserted a rivet in each hole and fastening it with a hand-operated pop rivet
puller. After all the rivets were installed, I wiped away any excess silicone with a paper towel, then taped a sheet
of bubble wrap plastic sheet over the outside of the door to protect the window during the remainder of the construction. I turned to door over and removed the black plastic tape from the edge
of the window, which also neatly pulled away the bit of silicone that squeezed out on that side of the joint. Then I
taped another piece of bubble wrap to the inside of the door to project the window. I repeated these steps in the same way for the left door.
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| Left door |
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| Right door |
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