Landing brake - part 2

Time for a brake! (9.0 hrs)

There is something cool about needing a landing brake. It subliminally screams FAST, and it's also going to be the first component of the plane to actually move as it's supposed to. Needless to say, I've been looking forward to this part.

With the landing brake recess cut and glassed, it was time to start manufacturing the actual brake.

I had a few pieces of 3/4” (19 mm) foam in my scrap pile, so I microed them all together to form a landing brake blank.  

Using West System micro to glue the foam pieces to each other

Landing brake blank curing at 72℉

Curing was taking too long, so I fashioned an "EZ bake oven" out of an Aircraft Spruce box.

At 140℉, it cured solid in no time!

Since I cut the slopes of the depression at 45˚, I setup my table-saw at the same angle, and quickly roughed up a matching outline.

This is so much easier than sanding!

Looks menacing already!

The panel fit into its recess a bit loosely, and was in serious need of some top sanding.

This is going to need a lot of sanding!

Following the instructions, I mixed up some 5 min epoxy, and placed small beads into the depression every 3” (7.6 cm) or so, then laid the foam panel back in it.

With the panel firmly attached to the underlaying fiberglass, the sanding started, and went on, and on, and on... you get the idea!

The original 80's landing brake was made out of urethane foam which was very easily sanded, but there were later issues with its strength, so the move was made by RAF to the much stronger, but harder to sand blue foam.

Polishing my cabinet making skills!

The two shims prevented the forward lip from dipping into the deeper part of the recess, under pressure.

Eventually the tough foam was sanded into submission, and a pretty nice brake started to emerge.

Gray tape was added once the final shape was achieved

This is where I deviated slightly from the plans, and took a different but proven detour.

Borrowing from Beasley’s experience, I used modeling clay to fill in the gap that had been created, so that the outer BID layup would bridge across it without any dips.

The clay will be removed before glassing the inside part of the brake.

I wish I could take credit for this smart idea, but it was Beasley's.

I think I've done this once before... in kindergarden!

Looks like a square blueberry pie, crust and all!

No need to be too precise here, somewhat flat will do.

Gap bridged, we are ready for glassing.

Last thing left to do was prepping the work area for 3 simple flat plies of BID.

When the epoxy started flying, I ended up needing all this protection.

I chose to reuse a small piece of BID, but I would do it differently now, and go with a full BID piece, since the scrap left a minute bump on the finished surface that could have been avoided. This will be fixed with the final outer coating, but I will try not to do this again on the exterior surfaces.

Reusing scrap bid. Bad idea on outside surfaces!

All three plies curing

You can't see it, but there's a tiny ridge where the scrap overlaps the rest of the first ply.