Replaced Upper Gear Leg Intersection Fairing Flange

The upper gear leg intersection fairing has a split in it to allow it to be flexed open and slipped over the gear leg. Once installed, a screw holds the split closed. Originally, there was a piece of fiberglass glued here with a small wood screw holding the joint closed. After repeated installation, the screw loosened up so I decided to replace it with a piece of aluminum and a nutplate. Now I can use a machine screw and there is positive locking of the screw with the nutplate. An added bonus is that the piece of aluminum forces the joint into alignment.

Here’s the other side of the joint with a torx machine screw and a countersunk washer.

Cleaned up Floxed Flange

I cleaned up the layer of flox I applied to the wheel pants flange.

You can see how much thickness it added to the flange.  The flange is much stiffer now and fits really tightly over the rear half of the wheel pants.  With the screws tightened down now, the flange no longer flexes and distorts.

Floxed Flange on Wheel Pants

The flange on the forward half of the wheel pants had gotten pretty thin over the top due to sanding to try and line up the surface with the top of the aft half.  There was also a gap underneath the flange which was causing the flange to flex down when tightening the screws.  I applied a layer of packing tape to the aft flange and some electrical tap to the joint.  I then mixed up some epoxy/flox and applied it to the underside of the forward flange and installed the pants.

Trimmed Flanges and Applied Filler

I trimmed the flanges so that there is only 1/4″ of underlap on the aft half of the fairing.

You can see in this picture and the one above that the aft intersection fairing doesn’t extend far enough forward in some spots.  I’ll take care of that with some filler.

I applied a couple of layers of electrical tape to the aft edge of the forward half of the wheel pant and then installed everything to lock it into position.

I mixed up some lightweight filler with flox for strength and filled in the low spots.

I squeezed some into the gap on the underside since the gap was uneven.

Worked on Lower Intersection Fairing Flanges

I needed to create some overlap on the flanges of the lower intersection fairings to prevent them from lifting in the slipstream, so I taped up the forward flange and then laid up some glass over the joint so it will bond to the aft flange.

On the right forward pant, I needed to extend the flange before I can create the overlap.  I taped up a piece of thick paper and then attached it to the flange.  I then laid some additional glass over the paper to form the extended flange.

I ordered a set of cowl inlet plugs from Bruce’s Custom Covers.  They look great and fit like a glove.

Adjusted Wheel Pant Brackets

I took the plane up for the first test flight with the wheel pants installed.  Everything seemed solid and the ball was still centered, so I guess I did a good job with the alignment.  On the taxi back however, I heard a funny sound coming from the wheels, so I pulled the wheel pants to see what was up.  I took a close look at all of the components and it was apparent that the bracket was being flexed into the brake rotor when the pants were installed.  I pulled the wheel and the bracket to take a better look.  You can pretty clearly see the mark that was being left on the bracket.  Fortunately, since this was stainless steel, the damage barely penetrates the surface and should be easy to remove.

The worst spot is right here and is still probably less than 10% of the thickness of the part.

You can see that the bracket was also damaging the brake rotor.  Since these are both steel, it looks like galling.

I used the scotchbrite disk to remove the marks from the bracket and then added an additional washer to push the bracket out an additional 1/16 of an inch.

I reinstalled the wheel pants and snaked an inspection camera inside to make sure there was still clearance between the bracket and the brake rotor.  Everything looked good, so I took it up for another test flight.  Problem solved.

More Work on Wheel Pants

I had another chunk of time today at the airport, so I decided to make a little more progress on the wheel pants.  I first drilled and mounted all of the nutplates on the mounting flanges.  These are stainless, so drilling them is a pain.

I also added 7 nutplates around the flange where the forward and aft halves of the left wheel pant join.  I also iterated a bit on the opening around the tire.  I now have 5/8″ of clearance all the way around with the weight on the tire.

With the pant attached to the mounting flanges, the left wheel pant is ready for flight.  I still have 2-3 hours of work to get the right pant to this stage, but then I’ll be ready for flight with these.

Final Wheel Pant Alignment and New Avionics

I put the plane back up on jacks and slowly enlarged the mounting holes up to #19 for a #8 screw while adjusting the wheel pants to be perfectly aligned with the longitudinal axis of the plane.  They were off a little bit when I started which is probably due to the epoxy/flox shims slightly shifting the position of the pants from when I first drilled them.  Since my brackets are stainless steel, I needed to use a fair amount of pressure to drill these, so I backed them up with some wood to prevent them from flexing in as I drilled.

After drilling these out, I pulled the wheel pants and gear leg fairings off the plane and to the plane back off the jacks so it’s ready for flight again.

Dynon recently released two new boxes that work with the SkyView system: one to provide dedicated knobs to control the altitude bug, heading/track bug and barometric pressure and another to provide a set of dedicated autopilot controls so that you don’t have to navigate through various menus to control it.  I’m mounting these in my radio stack with the outer edges flush with the other boxes in the stack.  This leaves enough room in the center for another small device if I want to add one.  I laid out for the holes, but it was too late to start cutting into the panel.  Once I have these mounted, hooking them up to the SkyView network will be pretty straightforward since I can just daisy chain them between the displays.