Openings

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Joining the two half cowls:

I took a simple method for accomplishing this.  I put some tape on the edge of the top cowl (for about three inches) so that the fiberglass lay-ups on the bottom cowl won't stick to the top cowl.  I then sanded the edge of the bottom cowl and prepared a layup of five pies of fiberglass material with epoxy.  I used the pre-preg method where the material is layed up on a plastic sheet.  Then a second sheet is put on top of the wetted lay-ups and a squeegee is used to take out the extra epoxy.  Then cut to size as needed, remove the top plastic sheet, put in place and remove the other plastic.  Very neat method and very clean compared to what I've done when I made the cowling.

To hold the two half cowls together, I clecoed pieces of aluminum on the outside of the cowling.  I'll repair the holes later.  I will also need to build a stiffener because the straight portion of the cowling is two flexible and it's hard to grab the inside lip with a fastener (now a cleco).

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The two eyes...

Ah... this is tough.  I don't know if I'm just being too tired of that cowling, but it seems I can't find an easy solution (this is written on June 19, 2003).  Initially, I tried cutting pieces of blue Styrofoam to the shape of the cowl to make the form, but I could not easily achieve the desired shape.  I also determined that it would be hard to lay up the cloth from inside around the rear portion of the hole.  

Next, I tried to make a form using a tube going through the opening.  Since the hole is not standard (can't just use a bottle or existing container), I tried making one using the plastic from a container I had.  That did'nt work well because the plastic was too stiff to take the proper form.  .016" aluminum showed a similar problem.  I then spent about one hour in a Reno-Depot store looking for a solution and over another hour at Wallmart.  I found a plastic material used for some kind of art that was flexible enough.  I tried with that and could not come up with a nice shape (the shape appeared distorted and the material was too soft).  

So, I decided to try another approach.  Put spray foam and shape the opening from outside. I used six cans of that spray foam and I created a total mess.  See below.  The problem is that while the foam expands, the core of the balloon is deprived from oxygen and does not expand and dry.  So, the core is mostly empty and there is an ugly syrup remaining in there.  Nothing can be done with this.  So, I spent a few hours to remove all the foam.

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I then tried another approach which would require lay-ups from outside.  I glued a piece of 1/2" round foam all around the holes and then applied a mix of epoxy glue and cotton fibers (flox) to shape the curvature of the flange.  Next day (it takes 12 hours to cure), I applied another coat of epoxy, but this time, I used micro balloon.   Whlie it was curing, I determined that it would be too hard to achieve a perfect shape, it's getting heavy and it takes too long.  So, I took a grinder and a sander and removed the epoxy and foam.  I had to repair a section of the fiberglass what was touched with the grinder.

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That's where I am... if you have any better idea on how to make these openings, please let me know (mtherr@yahoo.com).

July 16th update:  AH I got it!!!  

I decided to take a few weeks off that cowling work and assembled the canopy.  I got several advises on how to do it and when I came back to it, it went very well.  Pictures below are self-explanatory. (OH... sorry for the big files... I have a new camera and it was set in a fairly hi-res mode).

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