Nose and nose gear - part 26

Strut outer cover (13.8 hrs)

You are not going to find the “strut outer cover” anywhere in the plans. As a matter of fact I made up the name as I was writing this post. 

So, what is it?

Well, it is definitely not my idea. 

I am actually borrowing the concept from my friend Beasley, as I am trying to recreate his beautiful gear doors. Where did he get the idea, I don’t know, but he’s a very creative guy, so if he didn't come up with it himself, I'm sure he probably improved on the design.

Anyway, the idea behind the nose gear covers is to try to seal the nose compartment as much as possible, helping to prevent cold air infiltration that could affect the pilot’s legs at altitude (especially during winter), and improve aerodynamics a little.

Most Long EZs have the nose gear strut exposed and flush with the bottom nose skin, but my strut retracts further into the nose than normal, leaving an open slot that I will now try to backfill with foam and fiberglass. And while we are an the subject of foam, today’s story begins with finding enough of it to fill the gap.

Getting some foam to fit the channel

Countersinking some room for NG3

Foam glued to nose gear leg with 5 minutes epoxy

Note the wedge-like foam shape after sanding it flush to the fuselage bottom

I decided to add three BID plies in front of the strut (as seen when extended), and two behind it, sandwiching the leg. One thing to keep in mind is the need to leave enough room for these last two plies below the front three when doing the first layup (with the gear retracted). Failure to account for this could prevent the gear from retracting completely, and perhaps bend the outer strut cover, or even break it.

It turns out that two plies of BID are about as thick as four plies of duct tape.

2 cured plies of BID equal 0.023" (0.58 mm)

4 plies of duct tape equal 0.022" (0.56 mm)

With this in mind, I padded the area where the front layup would rest with four extra layers of duct tape, then I closed all gaps with the wheel well with Plastalina.

4 extra plies of duct tape added to both sides the foam

After cutting the fiberglass, and applying it to the foam, it was off to curing.

I used 3 plies of BID for the front side of the leg cover

"Sleeping beauty"

The next day I used a ruler to help me make straight cuts, and leave the cover about 3” (7.6 cm) wide.

Carefully trimming the new cover to size

Gear leg sporting the new cover (front part only)

The Plastalina was its usual pain in the neck to clean up, after which I trimmed the foam flush with the gear leg, and gave it all a good sanding.

Lot of cleanup to do on the back side

Plastalina removed, fiberglass sanded, foam getting trimmed.

All that was left to do was to prepare the two remaining BID plies, add a flox fillet to all 90˚ corners, apply the glass to the gear leg, and let cure.

2 BID plies getting wet

Same 2 plies in position after cutting a pass through hole for NG3 & 4

Letting it rest till the next day

The overnight wait was rough, all I could do was think about whether this leg would fit in its well once again or not, but you won't have to wait, you are going to find out right now.

So, did it fit?

Well… no, not really.

It kind of fit, but it wouldn’t close all the way, leaving a gap between the back side of the strut cover and the fuselage bottom, mostly on the strut end closer to the wheel.

This gap didn't exist before glassing the backside of the strut cover

Apparently the extra 2 plies of BID and the flox transition had swelled up the leg enough to create some tight spots. In some places the unwanted contact was was pretty evident, in others I had to use carbon paper to highlight the issue.

Carbon paper

Face down, the carbon paper is leaving a mark on the strut cover (SC)

Carbon deposits highlight area where rubbing occurs

Carbon transfer on the gear leg after turning the paper around

No need for carbon paper here, it's pretty obvious where the problem was.

More issues

Carbon = problem

The final check was done by slipping a feeler gauge between the gear leg and the strut cover (SC), and sliding it along the length of the strut while feeling for resistance, then sand as needed.

Feeler gauge would stick between the black marks

This process was very time consuming, but in the end it yielded good results, and I was happy with the outcome.

Gap is gone!

Testing the fit of the new strut cover

Nose and nose gear - part 25

Wheel well mod #1 (17.2 hrs)

I was expecting the same poor fit with the nose wheel cover (NB) as I had encountered with the strut cover (SC), and I was not disappointed. The blame for this was mostly mine of course. Deciding to retract the nose wheel completely within the nose structure (as it should be) caused the strut and tire to end up further upward than the pre-made SC and NB would allow for. 

Since deepening the strut cover worked so well, I decided to use the same technique to make the wheel well deeper also. I started by slicing NB near the bottom flange, where the curvature was minimal.

Cutting about 90% of the flange

To make sure the tire wouldn’t touch the top of NB, I added a foam spacer before capturing the geometry with aluminum tape.

Foam spacer

Amount of space to make up

New geometry fixed with aluminum tape

With the new dimensions locked in, I added tape to the other side, then removed the original tape from the side I needed to fiberglass.

Tape added to the opposite side

Original tape removed

The bottom flange was a little flimsy, so I nailed some tongue depressors to the foam in order to prevent the bottom flange from deforming during the cure process, and remain aligned with the actual opening.

Tongue depressors to frame the wheel opening

Test fitting the enlarged wheel cover

Using two plies of BID I closed the gap, then rested the new NB temporarily in its final location, after duct taping around the hole.

Adding the usual release tape

BID and peel-ply added to the cover

Wheel cover curing

A different perspective of the wheel cover location

The next day, after curing, I spent some time removing the aluminum tape from the tire side. As usual, the tape did not cooperate, and the task took a lot longer then it should have because of all the small pieces of aluminum left everywhere. I’m starting to have some mixed feelings about this kind of tape, it’s easy to put in, but tends to rip when one tries to take it off.

Note the pieces of torn aluminum tape stuck everywhere in the gap

With the tape finally removed, I sanded the surface of the gap, and filled it with flox. After another overnight cure cycle, I sanded it all smooth, like nothing had ever happened.

Sanding the flox I used to patch up the tire side of the gap

NB deepening mod complete

Meanwhile, I had more unfinished business in the form of another gap, the one I had cut into the fuselage floor. The reason for this was to allow the gear leg to come up further up into the nose, but it was time now to close it up.

Just as I did with the tire, I added a foam spacer to the strut to allow a little clearance space.

Foam spacer under the duct tape

Foam spacer sticking well above the fuselage floor

This accentuated the need for a flox ramp over which to straddle the fiberglass that would close the gap. So, I went to work on the two ramps.

First, I created two dams for the flox using old squeegees, then mixed and poured the flox.

Flox dams

Flox ramp

Same thing on the other side

These of course needed to cure overnight, but the next morning I was able to go to work shaping them with a Dremel sanding wheel, until they were as seamless as possible.

Flox ramps smoothed out

Right flox ramp closeup

Left flox ramp closeup

I was very pleased with how the ramps came out, and started prepping for the glassing operation by taping where needed while the nose gear was still extended.

Masking the bottom side with duct tape

Duct tape masking on the top side 

After raising the nose gear, I closed all the remaining openings with Plastalina. I had used this material in the past when I made the speed-brake, and found it very useful, although it always left a greasy film that needed to be cleaned up later.

Filling the voids

To straddle the floor gap, I used one ply of Kevlar within two plies of fiberglass.

Pre-preg

Hole patched

After one more night of curing, I was able to extend the nose gear, and start removing the Plastalina.

Plastalina needing to be removed

Fuselage turned upside down and Plastalina removed 

The final step in closing the gap was to glass the opposite side, and tie it to the strut cover structure already there. This was done with two plies of BID, after sanding all surfaces down.

Nose gear leg channel sanded

Two plies of BID finishing the gear channel

A little trim and a bit of sanding the next morning, and this channel was bridged.

The 4 plies of BID (2 on either side) reduced the size of the channel slightly

There is obviously more work to be done in this area

I was a bit worried about the fit...

...but it turned out perfect