Next was reinforcing the doghouse and doghouse opening. The “doghouse”, by the way, was my first clue that things were not going to be easy. If you look at “Task 2” on the task list, you’ll notice it says “Cut out Doghouse”. In the actual task list, it also says that task is in “Chapter 6”. But it doesn’t say WHERE in Chapter 6. There are 31 8 1/2 x 14 pages in chapter 6 with about 41 separate tasks. Some of these tasks do not apply since they were already done during the pre-build done at the factory (these steps are not identified in the manual so you have to read through another list to find out that it doesn’t apply to you). So the only way to find the steps involved with this task is to read through the entire chapter.

I eventually found the section on page 35. Which means the very fist step in building the airplane was in Chapter 6 on Page 35.

Go figure.

Anyway, I cut the doghouse out back in January. Where the cut was made is now raw, exposed foam on the doghouse and the fuselage. The reinforcing is supposed to be accomplished by first digging out some of the foam between the inner and outer skin and filling it with a mixture of epoxy and cab-o-sil. Cab-o-sil (called “cabo”) is an additive that is mixed with epoxy to make it thick.

 What that does is effectively cover the foam.  And while epoxy/cabo is strong in compression, it’s not very strong in shear.  So why not cover it with a layer of fine BID?

Here’s the front of the doghouse opening after I removed some of the foam between the inner and outer skins.

Here’s where I made another “engineering change”. Malcolm at Hangar 18 doesn’t fill the groove with just epoxy and cabo. He lays in a bundle of glass fibers the entire length on the groove. This creates an extremely strong arch. The only problem is that the fiberglass strands that he uses come in very large quantities that I would only need a fraction of. So I took some unidirectional fiberglass cloth (in unidirectional cloth, the glass fibers run in one direction only and are held in place with some small cross fibers) and stripped out the fibers by hand until I had enough to do both sides of the opening and both sides of the doghouse.

Here are the four bundles of glass fibers. Two short ones for the front and two longer ones for the rear.

Then it was time to saturate the glass with epoxy and embed it in the groove.

One of the bundles being saturated in epoxy.

Close up of the end.

Rear opening with epoxy/cabo mix ready for the “horsey tail”.

Once the fiberglass strands were in place I covered them with a layer of BID. After it cured, I needed to get the space between the canard and fuselage consistent. So I covered the doghouse side with a layer of duct tape and mushed in an epoxy/cabo mix in between. Afterwards, I pulled the tape off and I had a perfectly even gap between the doghouse and the fuselage.

Finished edge.