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Here I am bending the windshield hoop. I started by scribing the semi-circle onto my bench top. Then I make a bending jig at one end of the semi-circle. 8/1/00 |
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The jig is made from a couple of old bits of particle board. I used a radius of 12" on the jig to allow the hop to spring back as I bent it. 8/1/00 |
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Here is the hoop fitted to the fuselage. 8/1/00 |
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Here you can see the end of the hoop where it is bolted to the top longeron. 8/1/00 |
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Here you can see I have started on the windscreen. It is simply a flat sheet of Lexan (polycarbonate) that is wrapped around the hoop. The Lexan was easy to cut on my bandsaw and drilled with no sign of wanting to crack. I cleaned up the edges with a belt sander and rounded the edge with my deburr tool. 11/19/01 |
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I have left the paper cover on to help protect from scratches. You can see that the Lexan is a little thicker than the cowl fiberglass and leave a little hump. I might go back and thicken up the cowl so the transition is smoother. 11/19/01 |
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It is looking like a real airplane now. With the windscreen done I began working on the canopy frame. In stead of the square tube listed in the plans I am using round tube. I think the round tube will fit better against canopy bubble. I bent the round tubing the same way as I bent the solid rod above. I was worried about the walls collapsing but the gentle radius and the thick walled tubing prevented that. 11/19/01 |
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Here you can see canopy latch. I placed the handle farther back that called for in the plans. At Oshkosh, I noticed that the handle location on the prototype made it difficult to close the canopy. With the handle forward the canopy would twist and it was tricky to line up the latch in the slots. I am hoping the centered handle will help this. 11/19/01 |
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Here you can see I have fitted the corner brackets but I have not riveted them in place yet. This will leave me a little wiggle room to adjust the hoops. 11/19/01 |
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Then I went onto the canopy bubble. I marked the edges and used a Dremel with a cut-off wheel to trim the edges and then used a belt sander to smooth it out. I drilled the holes for the rivets on the hinge side with my special plexiglas drill bits. 11/19/01 |
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As I was clecoing the canopy side to the hinge I heard the first snap and a 4" crack rose up the side. After spouting profanity for an appropriate length of time, I continued clecoing and then I heard another snap. A second crack had jumped forth. Surmising that my first address had not been heeded, I launched into an even louder and longer oratory where I, among other things, questioned the canopy's lineage, compared its characteristics to type of fertilizer and suggested where it might go when I am done with it, however, not quite in those exact words. 11/19/01 |
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Hoping that I could still salvage the canopy, I stop-drilled the cracks to prevent them from spreading. I learned that you should support the back of the canopy so that the pressure of the drill will not spread the crack even further. Once the cracks were stopped I started to remove the canopy. But just as I lifted it up, snap, a huge crack went from the front all the way to the center of the canopy. Now my wife can hear me and begins to wonder if I am suffering from a severe case of Tourette's Syndrome. 11/19/01 |
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As you may have guessed, my first canopy was a complete loss and I ordered another one which I had more luck with. For the complete story you can read an article I wrote for the EAA Chapter 33 newsletter. The article is in Adobe Acrobat format. You can download the Acrobat reader here. 1/19/02 |
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Here is the finished product and I think it turned out well. I have left the protective plastic covering (inside and out) on the windscreen and canopy to protect them from scratches. I won't remove the covering until I am ready to taxi test . 1/19/02 |
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I nearly waited to long until I installed the retaining cable that keeps the canopy from opening to far. I scared myself a couple of times before I came to my senses and swaged the cable and screwed it on. 1/19/02 |
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Here you can just see the bracket that holds the cross brace. You can also see that I peeled back the edges of the protective covering on the canopy so I could install the screws. 1/19/02 |
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I was too chicken to use the rivets on the canopy sides. I used 6-32 screws and tapped the holes in the frame. With the screws it was much easier to adjust the amount of pressure placed on the Plexiglas. 1/19/02 |
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Here you can see how the latch fits into the top longeron and the spring that holds the latch locked. You can also see that I used round tube for the side rail as well as the hoops. The fillet of the aluminum angle that the latch is made of fits nicely over the round tube but would bind over the square tube. I also found that I did not need the nylon washer between the latch and the rail but I did use one on top of the latch, under the nut. 1/19/02 |
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As I said before I placed the handle in the center of the side rather than toward the front as shown in the plans. I find it much easier to control the twist of the canopy as I close it this way. I also put another slot in the side of the latch for a third screw. However this screw goes through the side rail horizontally rather than vertically like the other two screws. As you can see this gives me a trigger that I can use to pull against the spring which holds the latch in the open position as I line up the latch pins. 1/19/02 |
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