Overview of Chapter 12: canard installation

This chapter is pretty straight forward. It's only two pages in the plans - which made me nervous since it's usually the "this should only take 2 hours" that end up taking 2+ weeks.

The Long-EZ canard is bolted onto the F22 bulkhead using 5/8" OD bushings via the lift tabs that were installed onto the canard's spar beam. Upper tabs are added to the canard and locked in place using alignment pins. This locks the canard at the proper incidence angle.

The plan is as follow:

Alignment pins are made out of AN3-20A bolts. They are 2" long. Using an angle grinder, the heads of these bolts are cut off.

These pins are installed through the F28 bulkhead and into the doublers that are just aft of the F28 bulkhead. They are not floxed in just yet - just dry fit for now.

The canard is then shimmed leveled, aligned, incidence set, etc...

Once everything is where it needs to be, the plans has us drill through the F22 bulkhead using a #10 pilot hole. 

We then make the top tabs out of high-density foam, and use 5-min epoxy to bond them to the top of the canard. A 1/16" shim is placed between the F28 bulkhead and the tab to account for the fiberglass plies that will be placed behind the tab and for the CN2 bushing that will later be installed.

We then remove the canard and measure the thickness of the shims that were used on the fwd face of the F22 bulkhead. We then replace the shims with BID layups (each BID ply is about 0.013" thick). After cure, we back-drill the F22 holes. Also, the high-density foam tabs are glassed: 5 plies on the fwd face and 4 plies on the aft face.

The CN2 bushings are installed on the top tabs. CNL bushings are for the bottom tabs. The F22 bulkhead holes are opened up to 5/8" for the CNL bushings and floxed in place. Note that the CNL bushings must be trimmed to correct length depending on the amount of added BID plies.


Last step is to make the nutplate that is installed aft of the F22 bulkhead. This is found on the full-scale A7 page:

Oh, and then the alignment pins are permanently installed in place with wet flox.

Simple, right? Let's get started!

No comments: