Nose gear box

Here I will show you how I assembled my nose gear box.

I started out by making two NG8 disks - these are 2.8" diameter circular disks made out of 2024-T3 aluminum (0.125" thick) - these will be alodined later. I used a bandsaw to cut them to rough shape and then a belt sander to smoother them to a perfect circle.

I then aligned both NG30 panels and drilled the 5/16" hole... here I am testing the AN5-41A bolt...

Close up of the 5/16" hole...



I then drilled a pilot hole through the lower most NG51 bracket mounting hole (note that since I am installing Jack Wilhelmson's nose retract system, the lowest most mounting hole is really the second to lowest from the original plans).

To install the NG8 disk, I inserted a 5/16" positioning bolt through to center the disk and rotated it to obtained the proper bolt hole pattern orientation...

I then drilled the top most mounting hole...

Inserted an AN509-10R14 screw into place... and then drilled the next one... and so on...

Until all screws were in place...

On the outside face of NG30... I put AN960-10 washers...

Followed by MS21042-3 nuts.

Taaadaaaa - NG8 installed. Note this is just a temporary test fit - they will later be removed, alodined, and floxed in place.

Next it was time to install the NG51 brackets (the brackets that hold the electric actuator). Since I am going with the extended round nose - and therefore have taller NG30's - it's necessary to cut a 1" diameter hole to clear the actuator pivot bolt heads (if using the original plans built NG30, this would not be required since these bolt heads would be above the NG30 panel border).

So I started out by drilling a pilot hole...

And then used my router to mill out a 1" diameter hole...

Next, I inserted the AN5-41A bolt at the nose pivot with an AN970-5 wide area washer on the outside.

On the inside, I slipped on one of the tapered roller bearings with the pin (this came with Jack W's NG6 pivot casting)...

I then inserted the NG6 casting... this is the casting that the nose strut will bolt on to...

Followed by the other roller bearing...

I then sandwiched everything with the left NG30 panel...

Applied another AN970-5 large area washer...

And finally the AN365-524 nut that held everything together. The taper bearings allowed me to tighten it as hard as I could while still letting the NG6 to swing freely...

Now to mount the NG51 brackets - only the lowest most hole comes pre-drilled. This is to allow a custom match drill...

So I installed both NG51 brackets on the inside of the NG30 panels and then installed the actuator. You can see now what the 1" diameter hole cutout was all about... to allow clearnace of the bolts that mount the actuator onto the brackets. Having the brackets installed with only the lowest most bolts allowed me to rotate the brackets forward or aft in order to center the top bolt (with respect to the 1" diameter hole).

Here is an example of when it was forward....

Here is an example of when it was aft....

But center is what I was after... like this...

Once I was happy with it, I drilled the other mounting holes (through the NG30 and the NG51 bracket) - on the left NG30 ONLY!!!

I then uninstalled the entire assembly.... aligned the NG30 panels together... and matched drilled on through to the right NG30 panel. This is important because two of the mounting holes use AN4-41A bolts that go all the way through - so it's important that they align (these are used with the 3" spacers - I'll show you a bit further down).

I then mounted everything back and had an "oh-ohhhhh" moment - because my NG30's are taller than the original plans built NG30's... the actuator hub (the top gear box of the electric actuator) was coming in contact with the inside surface of my NG30 panels!

After contemplating back and forth, I decided to notch out a "V" to allow for proper clearance. This should have very little impact on jeopardizing the structural integrity of the NG30 panels.

Here is a side shot showing how the panels are no longer rubbing up against the actuator hub...

Here is a shot of the 3" spacers I was talking about earlier... this is why it is important to align the NG30 panels with the NG51 brackets and match drill the left side with the right side.

The bolts going through the two 3" spacers are AN4-41A. The bolts that do not go all the way through both NG30 panels are AN4-10A (I used AN960-416 washers on the bolt head side where it mates with the NG51 bracket surface). AN970-4 washers went on the outsides with MS21042-4 nuts.

The plans say there should be a 3.0" gap between the inside faces of the NG30's... mine was 2.98"... a 20 thou delta... completely unacceptable!! Just kidding... this will do!

So here is my nose gear box... ready to be mounted to the fuselage. I prepped the outside edges by sanding 1.5" in from where they will mate with the F22 bulkhead...

To make the installation easier, I removed the actuator and protected the brackets and spacers with masking tape...

I also prepped the F22 bulkhead by sanding the middle column (forward and aft faces)

I also prepped a clamp (made from the same threaded rods I had from when I assembled the fuselage together). Notice the 2x4 supports that will also help me install the nose gear box in place...

The NG30 panels then got a thick line of flox...

I then installed the nose gear box - making sure the bottom edges aligned with the F22 bottom edge. Before I could tighten the clamp, I needed a way to make sure the nose gear box was properly squared. I did this by shining a laser plane through the fuselage center-line. I then applied a piece of tape to the front of the NG30 panels and marked its center-point. It's hard to see in the picture below, but the tick mark on the tape was just left of the laser plane - this meant I had to tug the nose gear box slightly to the right (fuselage right - not picture right)

To do this, I tied a piece of string to the right threaded rod tip and pulled on it until the tick mark on the tap aligned with the laser plane. I then tied the string off to my nearby workbench.

With the nose gear box centered and squared, it was time to apply the BID tapes. Notice that I left the excess flox on - this provided a nice fillet for the BID tape later.

So I prepregged the BID tape...

And applied the BID tape to the inside corner. I should note that I brushed plain epoxy to the F22 and NG30 mating surfaces before applying the tape.

 I then applied BID tape to the other inside corner... this went a lot smoother than I had thought. I folded the BID tape into an 'L' (like an L extrusion), held it by the top, and dropped it in place. I then used a stick to lightly poke the edge into the corner. I then used my finger to smooth everything out and remove any air bubbles.

I then applied BID tape to the outside corners. Since the clamp was in the way, I only applied it half way down - after cure, I will remove the clamp and extend this all the way to the bottom edge.

Taaaadaaaaaa!! Nose gear box installed!!

After removing the clamp, I wanted to make sure everything cured properly square.... so I measured the distance from the top corner of the F22 bulkhead to the forward tip of the NG30. The red line must equal the blue line!! Mine was within 1/8" and I'm completely happy with that!