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.

Nose and nose gear - part 11

Nose floor (6.5 hrs)

In the heat of the moment I forgot that I had enlarged the fuselage, and neglected to enlarge the nose bulkheads... Doh!

I considered increasing the size of the bulkheads, and even remaking them, but after working out the lines over the plans, I realized that the changes to the nose shape were very minimal. Hopefully it will still look svelte.

Because of this, I enlarged only the rear portion of the floor piece... 

Modified floor plan dimensions

Duplicating the floor

... then went to work carving the front depression.

Deciding on a cut line

There's nothing subtle about this!

Making the depression symmetric

After mixing up some micro, I attached the foam floor pieces to the nose frame.

Getting ready to glue the foam to the fuselage

Duct tape and wood holding the foam in place while the micro cures

In order to provide a clearer surface for bonding, I elected to remove the bottom NG-8 bolt.

Depression clears the lower NG-8 bolt

I turned a couple of old bolts down to a point on the lathe, this will help spread out the glass weave as it is being laid over the hole, and prevent epoxy from filling it. 

Yes, I did poke myself on accident. More than once.

I did the same for the actuator bracket's bottom bolt.

More blood drawing spikes

A piece of paper served as a pattern for cutting the fiberglass.

Paper template

The foam was prepped with micro-slurry, and a fillet of dry micro softened all corners.

Micro-slurry closing the foam pores

Micro fillet

Then it was glassing time.

Fiberglass connecting the floor to NG-30, the front bulkhead, and the fuselage.

Layup complete

Peel-ply added

The next morning I ripped the peel-ply, and sanded the rough edges. 

Nose floor... ✔

Nose and nose gear - part 10

Stashing the nose wheel for good  (6.0 hrs)

I could spend hours talking about what a pain in the ass it was to drill the holes in NG-3 to match the ones in NG-4, but let's just keep it short. 

I wasted a whole day making a “hole duplicator” that not only didn’t help, but actually made things worse, forcing me to become overly creative once again.

This is the way it should have worked

The ¼" stud attachment fit into the hole perfectly

In truth, the duplicator might have worked on softer metal, where the drill bit could have gotten a quick “bite”, unfortunately the hard and slippery nature of stainless steel left the bit wondered about aimlessly, dragging the duplicator with it to all the wrong places.

¼" stud attachment

Hole for starter drill bit

Taper-center attachment (for random size holes)

Adding a “stabilizer bar” helped a little, but in the end it just was not up to the task.

Stabilizer bolt to prevent shearing motion

Improved hole duplicator in action

The day's work left me with 4 holes (2 per side) all of which were drilled off center, and a bit unsure how to proceed.

Pissed off, I threw the duplicator in the garbage, but after cooling down, I dumpster-dove to retrieve it, and will probably try it again in the future on aluminum or fiberglass.

Out of desperation, I ended up fitting the complete leg on my mill, and used 1/8” end mill to cut through the outer bracket.

No more "Mr. Nice Guy"!

I centered the mill’s head by eyeballing the situation in a mirror, and making the proper XY corrections.

Checking for approximate concentricity at best

Satisfied that I was as centered as possible with the preexisting hole, I stepped it up to a 3/16th end mill, and finally a 1/4” one.

Enlarging the hole to ¼" (6.4mm)

A 1/4” drill bit was used to reach down to the other side, and mercifully finish the job.

Though that was NOT the best way to do it, in the end the job got done anyway, "So what... who cares!" 

I was tired but happy when the gear leg got put back on the nose of the plane for final testing.

Second, and hopefully final gear extension/retraction test.

I did have to move the upper limit microswitch up slightly to reclaim all the additional space I had carved out of F-22, and I also had a slight rubbing issue with one side of the notch in F-22, and that got easily taken care with a little sanding.

Things are good again now, and I’ll be moving on to the nose floor and sides next.