Landing brake - part 1

Creating the depression (20.0 hrs)

The landing brake will be housed in a depression carved into the bottom of the fuselage.

Like plastic surgery, it all starts with a sharp cutting implement, and a lot of hope for the end result. 

"Nip and Tuck"

Fiberglass did not stick to the strategically positioned packing tape below it

As much as I tried holding the cutter at the 45˚ by hand, I kept steepening the angle for some reason, so I decided to rig something up to help myself.

Cutting a slot at 45˚

This worked very well indeed, and the plywood panel fit nice and snug into the slot at the required angle.

The hinge will attach to the plywood, after it gets trimmed down

Because I still needed to cut the actuator slot into the fuselage floor, I tried the “carpenter square” method again, with equally good results.

Vertical milling

And voilà,  a landing brake actuator hole!

The plans call for carving a 0.5” to 0.6” depression into the foam. As I did in the past, I used the router to clear up the foam in a consistent matter.

A "depressing" job

Clearing the foam

Edges sloped at 45˚

Up until this point everything went pretty fast, but it only took one dumb decision to deviate from the plans sequence of events, to put the stop to that!

I thought that it would be simpler to drill and tap the aluminum blocks before attaching them to the fuselage. While I was right about that, I didn’t anticipate the amount of work, and headaches this would create for me later.

Aluminum blocks erroneously tapped before installation (don't you do that!)

Aluminum blocks epoxied to the plywood (swimming against the current now!)

Needless to say, I should have followed the plans. What was I thinking?

To prevent micro-slurry from getting into the threaded holes I tapped into the blocks, and that should not have been there in the first place, I had to make something to plug them temporarily. So, I shortened some bolts I had, and cut slot into them to allow me to remove them later with a screwdriver.

Trying to dig myself out of the hole

This ought to keep the evil micro at bay

After carving more foam to clear the actuator brackets, I microed the plywood into the slot I had carved, and went to bed.

Plywood, aluminum blocks, and headless bolts microed in place

Done for the day

The next morning, I prepped the fuselage for glassing by taping around the depression, and putting dry micro into every sharp corner.

Ready for surgery

Smoothing all corners with dry-micro

The plans require 2 full plies of BID, plus a third smaller ply over the hinge section only. I elected to lay the smaller ply first, so that I would have a smoother transition without having to use extra peel-ply across the layup.

Reinforcement layup

2 full size layups

All 3 plies in place

Lastly, I trimmed the fiberglass all around the perimeter, and peel-plied over it.

Edges trimmed, and peel-plied

A better angle