Although I've taken the summer off from blogging, I've continued to make progress on the project. This step in the project occurred in late June.
With the canopy cut and the edges smoothed, its time to begin the process of attaching the plastic to the aluminum. There are two main methods of attachment, glue or screws. The Van's way is to use screws, which is the simpler of the two as it allows one to fix one point at a time. The glue method, on the other hand, requires that the entire canopy be fixed at once. The glue method does offer one important advantage in that no holes are drilled through the plastic. It has been observed that canopies with cracks tend to begin cracking at a drilled hole. And thus the genius of the glued canopy is revealed -- no holes drilled equals no place for a crack to form.
With the canopy cut and the edges smoothed, its time to begin the process of attaching the plastic to the aluminum. There are two main methods of attachment, glue or screws. The Van's way is to use screws, which is the simpler of the two as it allows one to fix one point at a time. The glue method, on the other hand, requires that the entire canopy be fixed at once. The glue method does offer one important advantage in that no holes are drilled through the plastic. It has been observed that canopies with cracks tend to begin cracking at a drilled hole. And thus the genius of the glued canopy is revealed -- no holes drilled equals no place for a crack to form.
Before gluing the canopy on I thought it a good idea to paint the cowling under the canopy black to reduce reflections. After the canopy is in place, the clearance is too limited to attempt painting in there, mostly due to the slope of the canopy. And so I mask off the area to be glued and paint the rest black.
Next we test fit the canopy one last time and fabricate some mechanical tie downs that we can rivet in place to hold the canopy while the glue cures.
I use a wire to act as a spacer in between the canopy and the side rail. This ensures that there will be enough glue in place for a strong bond. The danger here is that without the spacer, the canopy could contact the rail an squeeze out the glue, preventing a good bond.
The next step is to apply the primer to the plastic and the aluminum.
Then the real fun begins. Squeezing out the glue.
During the gluing process it is necessary to get inside to scrape off the excess glue. Getting back out is the hard part. Here I am trying to climb back out through the baggage compartment.
With the glue on and the canopy in place there is nothing to due but wait.
I really enjoy these moments in the construction. Applying glue brings a kind of clarity to process. There is 'before glue' and there is 'after glue' and nothing in between. Black and white. Once you've mixed the epoxy or squeezed out the glue there is just no going back, It's all ahead forward. It's at these times that one really knows where they are.
It frequently happens that people ask me how I'm doing on the airplane. The engineer in me struggles with this kind of question because I feel obligated to give an exact answer. Most of the time I have a half dozen different subprojects going on simultaneously each involving many subparts and their attendant issues. I don't really want to stop and calculate the precise level of completion that the question requires -- partly because I always realize that I'm not as far I along as I had previously thought, but also because the questioner would probably get bored and walk away while I mentally tabulate the answer.
In the end, I know that the questioner really doesn't want that kind of detail so I usually politely answer, "Oh, its going fine."
But on days like this, when I've completed a major milestone, I'm happy to add something like, "I just attached the canopy."
Curiously, I failed to photograph the canopy as it looked while the glue cured, so I add this one which gives a preview of the next step in which we fiberglass the edges of the plastic down to the aluminum cowling to form a smooth fairing.
Curiously, I failed to photograph the canopy as it looked while the glue cured, so I add this one which gives a preview of the next step in which we fiberglass the edges of the plastic down to the aluminum cowling to form a smooth fairing.
Why does this dog keep photobombing my blog?
