More Cowl Adjustments (9)

9 hours

OK, now I'm really getting down to the last few things (I think).  I can not fathom any way to get the upper cowl on and off, the way the plans have it attach, with the prop installed.  So, I decided to slightly modify the aft edge of the cowl so it doesn't have to be wedged under the lip on the front of the windshield skirt.  Then hopefully it can be installed and removed vertically and stay out of the space that the prop is occupying.

Here is my inspiration.  This is an RV-8, and this picture is from the Skybolt website (which is where I got all my cowl fasteners anyway):

So, I will cut the aft 1/2" or so off of the fiberglass, remove the female Skybolt receptacles, install a bunch of those little tabs, put the receptacles on the tabs, and then the cowl will just sit on top of the tabs with the fasteners holding it down.

First, I removed the prop so I could get the cowl on.  Then I traced the front edge of the windshield skirt onto the cowl, and removed it.  Then I drilled out all of the receptacles, and then cut along my line to remove the aft edge of the cowl.

The little pins that hold the clip out on these fasteners while they're adjusted were all long gone, so I made some replacements out of safety wire.  I later found out that these fell out a little too easily, and the stems from 3/32" rivets actually worked much better.

Next I made a bunch of tabs, and drilled them for the receptacles.

I went across the windshield skirt, and attached a tab at each spot that previously had a receptacle.

It was tricky to drill the cowl to the existing holes in the tabs.  I located some of them by putting a flashlight underneath and spotting the hole through the fiberglass, but I had to do a few by just measuring and hoping I hit the hole in the tab when I drilled through my mark.  Eventually I got all of them though.

I don't have a good picture of it, but I ended up making little 1/16" thick strips as spacers to put between each tab and the underside of the skirt.  That brought the upper surface of each tab down enough to make the top of the fiberglass pretty close to flush with the skirt.  It was also totally required in order for all the fasteners that held the upper and lower cowl pieces together to still fit!

The only real issue remaining is this gap in each corner.  I don't think there's any way I can flex the cowl enough to follow that contour.  I think I will just add some filler or something later to build up the fiberglass enough to cover these gaps.

After many, many iterations, I got all the fasteners to line up correctly, and now the cowl can be dropped straight down into place without needing any extra room at the front.  I reinstalled the prop and called it good enough for now!

Here's a good depiction of the extremely minimal space between the cowl and prop.

I will come back later and address these little gaps in the corners.