9.2.5 Lower Strake Half Glassing

The strakes have to be permanently attached to the center (main) spar as well as the side of the fuselage. Structural epoxy is used underneath while standard 2-BID layups using EZ-Poxy are used on the top. The photo below shows the layup attaching the strake to the top of the spar.

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Layup attaching the bottom strake half to the main spar.

I showed this photo and the next one earlier, but just for review, the wood blocks, shown below, are used to temporarily hold the strake in place against the fuselage. The next photo shows the I-beam and scissors jacks that I used to apply pressure to the bottom of the strake while the structural epoxy cured. That process worked well!

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Small wood blocks are hot-glued into place to help support the strake before doing the internal layups.

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For epoxying the lip of the lower strake to the lower wing, I need some way to compress that lip so that it's as tight as possible. Three scissors jacks and one of the old I-beams used to help make the wings solves that problem!

There are additional layups that lock the strake to the side of the fuselage. These are also 2-BID layups. The middle layup actually wraps around inside of the fuselage through the baggage compartment opening, as shown below. Finally, another layup locks the outside of the strake to the outside of the fuselage as shown in the 2nd photo below. Before laying up the BID, EZ-Poxy plus Micro is spread at the junction between the strake and the fuselage. BID doesn’t like 90-degree angles so the application of a finger's-width of Micro helps to smooth the transition to help the BID lay straight. A little peel ply also helps!

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In addition to the layup at the back, there are layups along the side of the fuselage as well as one into the fuselage through the baggage access hole.

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Finally, there's one last layup that attaches the bottom of the strake to the side of the fuselage.

There is one other step that I’m not showing here. Because part of the lower strake extends over to the wing, once the structrual epoxy cures a cut needs to be made to release the strake from the wing. Later, finishing work on the bottom of the  wing blends that little strip of strake into the wing.

One other small step I need to mention is the creation of an access hole in the bottom of the strake. In order to attach or detach the wings, you need to get to the bolts and nuts. This hole (which partically gets covered by an aerodynamic plate) provides for that access. The manual specifies a 3” round hole. Well, try to get your hand, plus a wrench, inside of that small of a hole! After talking to the factory, they recommended an oblong hole that’s also a bit larger in diameter. And that’s what I did. The hole is about 3 3/4” in diameter and is obviously oblong. The factory said they just attach the cover with some silicone caulk but I decided that was a bit tacky so I added nut plates so that the cover can be bolted on. That’s much cleaner!

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Wing bolt access hole - plenty big for my hand and a wrench!

So, now that the bottom half of the strakes are attached, it’s time to start building the fuel tanks. Section 9.3.0 covers that involved process!

ui© John Trautschold 2018