Nose and nose gear - part 14

Nose left side panel (8.0 hrs)

Luckily for me foam is easily repaired, because I had another “senior moment” while measuring the height of the left panel, and I cut the foam 1” (2.5 cm) short. I thought about cutting a new panel, but this foam is just too expensive to discard, so I cut the missing slice, then glued it back to the main piece.

Amount to add to the incorrectly cut side panel

Foam slice cut, glued, and pinned to the side panel.

After fitting and adding more scrap pieces to it, the left panel emerged just as weird looking as the right one did...

At least they are symmetric

... and since glassing it on the bench, then taping it to the nose when cured worked out so well for the right side, I decided to continue the same way.

Left panel glassed, and peel-plied.

I must have been very tired, because my quality control was terrible that day, and the next morning I found a bunch of medium to small air bubbles under the cured fiberglass (not good).

Air bubbles marked

Unfortunately there were just too many bubbles to just go drill and inject epoxy into. 

This situation was unacceptable. 

I decided to make a structural repair by sanding over the offending air bubbles all the way down to the bare foam, and glass over them with greater care.

Foam and fiber craters

2 BID plies over the depression

Peel-ply action

Peel-ply removed the next day

Trimmed, sanded, and ready for use

Waiting for the panel to cure again cost me another day of building, but I felt a lot better about the integrity of the construction, and I moved on to glueing the left side to the nose.

Very thick wet micro (to prevent running)

Left panel pushed in position

Excess micro overflow

Excess micro removed, panel shimmed and tied in position.

While the West System micro quickly hardened in the above 90℉ shop temperature (> 32℃), I got my BID tapes ready to go...

BID tape readied

... and got started on the flox fillet.

Flox fillet being applied to joint

Flox fillet following the joint

The last step of the day was applying the BID tape, and peel-plying everything.

BID tape application

Same thing looking forward

4 ply top corner reinforcement

Forward section peel-plied

A longer shot of the connections

The following morning I removed the peel-ply, sanded the leftover strands of Dacron tape off, and trimmed the excess glass.

Peel-ply removed, and leftover peel-plies strands sanded off.

Same thing looking toward F-22

So, this is what the nose looks like today (it will be shaped and glassed later on)...

Nose left side

Nose right side

Top view of both sides

Nose and nose gear - part 13

Nose right side panel (5.6 hrs)

For the life of me, I couldn’t cut a piece of foam that would fit properly in the space between F-22 and the nose bulkhead, so I settled on an “incremental approach” where I would add scrap pieces and micro as needed to fill the voids, the less the better.

Minimizing the gaps

Foam scraps pinned temporarily

Testing a corner piece for size

Corner piece trimmed and pinned

I came up with a pretty weird looking chunk of foam, and I carved a small depression in the rear half of it to make it match the F-22 leg cutout. In the end the leftover gaps were quite minor, and were later easily taken up by dry micro or flox.

Final right nose piece configuration

To make things simpler, I decided to glass the panel on the bench, and let it cure overnight.

Going to work

Glassed and peel-plied

The next morning I glued the panel in position with semi-wet micro.

Side panel "microed" in place

Detail of the front side

Nails used to prevent the foam from sliding inboard

Clamp preventing the foam from falling out

Later, I used BID tape to make all the structural connections.

Cutting BID tape

Flox fillet

Bid tape connecting side panel to F-22

More BID tape action

"All you can eat" BID tape

After a further curing cycle, I trimmed off the excess glass, then decided that the BID tape overlap between the side panel and F-22 seemed to be less than 1 inch in a few spots, so I added a wider piece to make certain I tied the two vertical structures together.

Area to be glassed

2 plies of BID over epoxy and Cabosil, backed with plastic sheet.

Plastic removed and peel-ply added

Last but not least was another 4 ply BID piece that strengthened, and tied together the top corner of F-22 and the nose left side panel. Unfortunately I didn’t take any photos of that, but I will shoot some when I do the right one.

Nose and nose gear - part 12

Floxing the nose leg hinges (1.0 hrs)

The time had come to permanently attach the metal hinges to the nose gear leg extremities.

Every time a metal casting is attached to a fiberglass part, the slack between the two is taken up with flox. This technique allows for a perfect custom match by displacing the excess material from the joint.

I started out with the top hinge...

Floxing the top plate

Excess flox being expelled from beneath the top plate

Applying flox to the top hinge

Pushing the hinge down onto the leg

... then finished the bottom one.

Floxing the lower casting

Leg mated to lower hinge casting

Buttering up the front side of the leg

Bolts in place, but not tightened to final torque.

View from the far end

Flox taking up the gap

After cure, all the bolts can be tightened to their proper torque values.