Making the strut cover

The plans say to purchase the strut cover prefab... and while there are a few 'garage companies' that make them, I decided to make my own since I wanted a custom fit.

I started out by studying Drawing A6 - and the more I looked at it, the more questions I had. Where does the strut cover exactly begin?! (indicated by the blue line below). And what is that piece just aft of NG31?! (the outlined piece indicated by the red arrow below). The plans aren't very detailed in that it only tells you something along the lines of "go ahead and install the strut cover" and "go ahead and install the nose bumper".

 So I kept looking at the drawing and looking down from above the NG30 box to figure out exactly how I wanted for all of this to work - and then formulated a plan. I needed to come up with a way to make a cover that was about 0.25" offset from the strut surface and later glass the gap between the cover and the bottom of F6 (or in my case, F4.1 since I'm following the extended nose mod). The plans don't mention anything about sealing up this gap, but I figure closing up as many gaps as possible will keep cabin noise down to a minimum.



I looked underneath and noticed that the strut follows the bottom NG30 contour pretty darn well - so I could use this as a template for my strut cover.

I removed the strut from the airplane (for the 2349872345981234 time) and cut a piece of scrap Home Depot type foam to the length of the strut. Also, notice how I marked where the NG4 rectangle goes and used a knife to cut it out.

I then covered the strut with masking tape (to protect it from what was to come)... and applied cheap Elmers glue to the front face of the strut.

I then glued the foam board onto the strut and weighed it down enough to make sure the foam followed the contour of the strut. This is very important since this will define the curvature of the strut cover's flanges.

After the glue had dried, I flipped the strut over on my bench. It was now time to make the 0.25" offset mold.

So I made a bunch of 0.25" thick strips of foam (sliced them using the bandsaw). These will get glued onto the strut to make the offset mold.

Noticed how the foam board curves - following the strut contour. This is why I had to cut the NG4 rectangle out - to get a nice flush bond.

I then taped a piece of foam to NG4 so that the strips of foam would bow out - allowing room for the actuator bolt.

Elle came along to help and applied hot glue along the foam strips... and bonded them to the strut sides.

Notice how the strips bow out... giving enough room for the actuator bolt to fit.

After the sides were bonded.. it was time to add the lid.

I applied hot glue to the top edges, and installed the lid.

I taped the areas next to the bow to prevent them from de-bonding.

Next, I cut a piece of foam to seal the box.

And hot glued it in place.

I then sanded all the edges nice and smooth with a radius. This will allow the glass to contour the surface pretty well.




Ooooooooooo... looking gooooooood!

Before glassing, I added a fillet between the box and the platform using cheap kitchen calk. Again, all these materials (home depot foam, Elmers glue, hot glue, kitchen calk) can be used here since it's only to make a mold for the offset surface. After the glass cures and the cover is removed, these materials will be discarded.

That's a nice looking fillet!

With the mold completed, it was now time to glass it. I tossed up different ideas on adding some sort of release agent under the glass (tape, cling wrap?) - but I opted to leave it out since I thought it would disrupt the fiberglass from looking like the mold.

Here's ply #1 (BID at 45 degree bias)... I didn't slurry the foam since I didn't want the glass to bond to the foam. I'm only using it as a mold.

Wetting out ply #1... I used a brush to paint the epoxy on...

Ply #2...

After wetting out ply #2, I added peel ply to the flanges. These flanges will later get bonded to the bottom of NG30's.

Cure baby! Cure!

The next day, I pried the cover off of the mold. This is where I regretted not using a release agent! I thought that since I didn't use slurry on the foam, the glass wouldn't bond to the foam as well as it did - but it did. So I began to remove the foam using a scraper and sandpaper.

That's a nice looking strut cover!

It needs a little bit more clean-up on the inside... but overall, it came out great! I will later fine trim the flanges when it comes time to install it in place.