This is an update to the previous post. I am working on the modification of the Canopy frame to accept the instrument panel and increase the knee room. I laid out the trim of the solid bulkhead and then cut it out of the existing frame. The biggest problem was how to reinforce the core under the instrument panel attach screws. The core is 4.5lb/cu ft urethane foam. It will immediately crush when the screws are tightened up. I marked the location of the screws and then used a 1/4" drill to route out all of the foam within a 1/2 inch in each direction. The void will be filled with dry Micro balloon. This is Micro mixed to the consistency of dry dough. To ensure a good bond, the cavity is coated with raw epoxy.
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| Bulkhead and lower shear pane trimmed out |
The tab outs are around the fabric stringers. The attach screws are between each of the stringers.
The plywood gussets are designed to smoothly transition the fabric from a faceted flat to the curve of the bulkhead.
This is a good picture of the tab outs. The urethane foam core is shown. The lower shear panel was cut back, this exposed a Styrofoam edge. I do not like raw Styrofoam in the fuselage. One time during the Lakeland Airshow when I was building the Wren, one of the only other manufactures I ever met who was not very friendly came up to me and started yelling at me??? He complained that I was pushing the spirit of part 103 and I should just go back to Kansas and stop this madness!! He was quite famous and unfortunately(or fortunately) he is no longer with us. He was criticizing me for building a fuselage out of Styrofoam. Evidently he didn't level the same criticism at Steve Wood for his Sky Pup, but in any case, he told me that a single gas spill could drop me out of the air!! That night around 2 am I heard a noise outside my camper , when I ran up to the Wren, she was soaked in gas. The whole lower panel was dissolved away. I sat up all night and repaired the fuselage by splicing in foam with 5 minute epoxy. I completed all of the repairs 30 minutes before the ultralights flew later that day. When Mr Pseudo-famous walked by the flight line, the look on his face proved beyond all doubt he was responsible!!
Anyway, that's why I don't like Styrofoam in a primary load path.!!
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| Shear panel close out |
This is the closeout of the exposed shear panel edge. The technique here is to cut a 45 degree wedge away from the foam up to the cured glass. Dry Micro is then forced into the corner A layer of glass is then laid up over the exposed foam. When the micro cures, it forms a wedge shaped gusset. Once its fully cured (72 hours @74 degrees) the edge will be rounded over with a sanding block to keep from scraping the pilots legs.
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| boo saving me from a Frisbee attack |
I live on the edge of the Hill country about 40 miles south of Dallas. Just south of me about 10 miles, it starts to open up like the Texas you see in the movies. There are lots of wild animals and recently there have been a number of pet dogs and cats that have been attacked and killed by mountain lions. But that's not the nastiest threat we have in Midlothian. While I was working away out on my shop minding my own business, a wild Frisbee attacked me, luckily My good ole boy Boo was there to protect me!! I'll tell you, I will never have any dog other than an Australian Shepard. Its really fun to have a very smart dog!!
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