F6 (my F4.1) and forward nose strut ramp

It's amazing how just when I think I caught Burt of missing something - it shows up in the plans!

For a while now I've been trying to figure out what that ramp (circled in blue on Page A-6 below) was and how it's made. After re-reading Chapter 13 - I finally caught it - Chapter 13, page 10, second to last paragraph "Fit and bond with 5MIN, a few small urethane blocks around the gaps at the front of the nose strut. See A6"

That is the mysterious piece I was questioning about this whole time! It's simply made to seal the gap between the top edge of the nose strut and aft face of NG31 (F1-3 if you are doing the extended nose mod).

As for the nose bumper - that gets installed after the outside of the nose is glassed - the area just under F1-3 gets beefed up with 4+ plies of BID and the tire puck (the nose bumper) goes on top of that beef up.

Case and point - it's the bottom of F1-3 and the beef up that supports the nose bumper - not the ramp piece just forward of the nose strut that is shown in A6 (the ramp looking piece circled in blue below).

This is drawing A6 per plans... F6 (circled in red) is my F4.1.


 This is the extended nose mod. Notice how F6 in the original plans is my F4.1 (circled in red below) - I will show you how I installed this bulkhead in this post as well.

Installing the ramp piece before installing F4.1 is probably a wise idea since it gives you more room to play with - so I started with that. Notice the gap between F1-3 bulkhead and the forward edge of the strut.

Here's another view of it from the inside. The foam piece that will plug this gap needs a rounded ramp shape to allow the strut tip to clear as it is extended and retracted.

Here I am manually extending and retracting the strut to get a feel for what radius the ramp should be.

I just eyeballed it and cut a ramp with the band saw...

And test fitted it...

Not bad for a first go! I intentionally left the ramp hanging long so that I can sand it flush with the rest of the nose later. I fine tuned it and found its prime location such that the strut could extend and retract without interfering with the foam.

Alright, now to install this thing. I started out by sanding all surfaces smooth... notice how I drew a horizontal line so that I knew where to reinstall the ramp in its prime location.

Slurried the ramp...

Installed it into position and applied flox to all edges... notice the clear tape to protect the NG8 disks...

I then prepregged two plies BID at 45 degree...

And installed the prepreg. I made sure to remove any air bubbles... the flox did a nice job of transitioning the preg from the F1-3 aft face to the foam ramp and NG30 forks.

After cure, I trimmed the overhang and sanded everything smooth.

I reinstalled the strut and double-checked to make sure the top of the strut cleared the ramp - perfect-o!

I couldn't have asked for a tighter clearance!

Notice how the ramp overhangs a bit - this will be sanded down flush with the rest of the nose contour later.

Ok, so we have the ramp in place - now to install the F4.1 bulkhead (called F6 in the original plans). I sanded the mating surfaces smooth...

Mixed up some slurry (for the foam), flox (to install F4.1 onto the NG30 forks) and plain epoxy to do my prepreg...

Slurried the foam (recall that the backside of F4.1 had already been glassed)...

And applied a nice amount of flox to the backside edges...

I then placed it into position...

Rather than wiping the excess flox off, I kept it and used it to transition between NG30's and F4.1.

I then prepregged 2 plies of BID at 45 degrees... and placed it into position..

I removed any air bubbles and lightly pressed along the edges to get a nice smooth transition.

Here is a picture showing the inside - between F1-3 and F4.1. Notice how the flox formed a nice fillet along the edge...

After cure, I trimmed the overhangs...

And there you have it - F4.1 and the ramp thingy installed! Next up is installing the strut cover and NB nose box cover!