8.1.2 Install Main Gear Axles

The first step is to mark one of the legs, per the instructions in the manual and do a test fitting to make sure that the axle fits properly. I started on the right leg and got that axel mounted. After making sure that the fuselage is back to being perfectly level, left to right, I then use a string line with a string line level to transfer the center mark from the first axle to the second. You can see the string line in the photo below.

Fuselage - Main Gear Axle Installation

The holes for the right side axle are drilled so I use the string line to transfer those measurements to the left side leg.

Fuselage - Main Gear Axles

I need to transfer the height of the first installed axle to the other side.

The photo below is just another test fitting. I won’t permanently install the axles until after I received the finished “booties” from the factory. I’ve decided to install these steel booties in order to help dissapate heat buildup. Some builders have had issues with the gear legs “melting” and deforming from heavy braking. The bootie helps to solve that problem. In the meantime, I’ll purchase some shorter, temporary bolts to lock the axle in place so that I can put the wheels and tires on.

Speaking of steel, check out the gray plate to the right of the silver spacer. That gray plate is part of the Cleveland wheel assembly that holds the brake assembly. Unfortunately, the pre-drilled holes in that plate don’t line up properly for our purposes, so the manual has a procedure for “fixing” that by drilling two new holes. The factory told me that drilling those holes will be difficult because the plate is made out of an extremely hard steel. Ya think? I first tried drilling it with my harded titanium drill bits. Well, that didn’t work. The bit went dull in 5 seconds flat. So I bought 10x hardened cobalt drill bits. Those worked, but even they went dull after a couple of holes. I had to buy some replacements, and they aren’t cheap! Yikes!

Fuselage - Main Gear - Temporary Axle installation

This is basically a test fitting. I'll do a permanent installation later.

In addition to drilling out the holes, I need to grind away some of the bottom of the leg to make room for the Cleveland brake assembly which needs to be mounted at an angle. I temporarily placed the brake assembly on the mechanism you see above so that I could trace out what needed to be removed. I had to be careful not to remove too much since the axel holes are already close to the bottom. The photo below is the end result.

Fuselage - Main Gear Leg

The main gear axle and brake assembly is held on with four bolts. In addition, the bottom of the leg needs to be shaped so that the Cleveland brake assembly fits properly.

I’ve also decided to install the optional steel “booties” as the factory calls them. Because the gear legs are made out of carbon fiber and epoxy, with some sort of core material, people have had problems with them literally melting and deforming after a hard braking situation. Because I’m flying from a higher altitude airport, my landing speeds will be higher so I’ll definitely be doing some braking. These steel booties act as heat sinks. Scott made these for me. This is the initial test fit. After I lined them up and drilled the holes for the axel bolts, I needed to temporarily bond the rear plate to the front section to keep everything aligned. I then send this back to Scott at the factory. Because the gap with the curved section is too big, he’ll shorten that up a bit and finish welding the entire thing back together.

Fuselage - Main Gear Bootie

Test fitting the bootie for the left main gear leg.

So, at this point the booties have been returned from the factory, all welded together. They fit perfectly. There are gaps, however, that need to be filled with EZ-Poxy plus Microballoons. The photo below shows the assembly reinstalled along with the axle and the brake assembly. 

Filling the gaps between the gear leg and the booties was, shall we say, “fun”. I had to keep the epoxy from oozing out of the bottom and the various bolt holes, so after bolting everything back together (using grease to keep the epoxy from sticking to the bolts and washers to help keep the stuff from oozing out around the bolts), I started by making up a really thick mixture (putty-like) of epoxy and micro balloons that I stuffed into the bottom. After letting that cure for a day I now had a sealed bottom. The next mixture was much more runny so that I could carefully pour it into the gaps. It filled in fairly well but I ended up doing it in two pours. I let the first one settle and harden, then came back the next day to pour a bit more in to fill in the gaps. In the end, the assembly seems to be locked solidly into place. I hope I never have to remove these booties. it’s not going to be fun if I do!

IMG 2174

Completed bootie. It's now filled with epoxy to lock it in place.

Here’s a photo showing the installed and filled bootie, along with the tire installed. I think it came out fairly well! The brake assembly is not installed in this photo. I’ll do that later.

IMG 2175

Here's another view of a completed bootie. The brake assembly is not yet installed and I'm using temporary bolts to hold the axel in place.

The gear legs need finish work before they can get painted. While the fuselage is upside down, I decided to start doing that finish work on the main gear legs. It’s much easier to do in this position!

IMG 2372

The first finish coat is applied to the landing gear legs.

ui© John Trautschold 2018