Finishing Kit

April 24, 2012

The Nose Wheel - 14.0 hrs.

I'm taking a break from canopy work for a while. There are lots of other sub-projects pulling at my attention, and I decided to indulge my temptations a bit. I've been pretty firm about not allowing myself to get sidetracked in too many directions. It would be very easy at this point of the project, but to do so would lead to feeling overwhelmed at times. Too many irons in the fire, so to speak. Nevertheless, today I decided to do something totally different. I pulled out my nose wheel and decided to assemble it. I thought this would be something I could whip out in an hour or two. Boy, was I wrong. This page is a compilation of work I did on the nosewheel over the course of about 6 weeks, extending into the middle of June. I was gone the early part of May on a trip to San Diego anyway. It's exciting to work with the wheels, and think about actually having my airplane on her gear. I'm looking forward to that day.

Here's my Matco Nose Wheel, separated into two halves, along with the tire and the tube. First thing I did was to shake some talcum powder into the tire and shake it around to coat the inside walls of the tire. I also rubbed talcum all over the tube. With the tube inflated about halfway, it was easy to work it into the tire. So far, so good.

Next, you simply put the two halves of the wheel together, being careful to avoid pinching the tube, and bolt the wheel together. Then I aired it up and deflated it a couple of times, and finally aired it up for good. Looks great so far.

The Matco wheel assembly, as well as earlier Cleveland versions, uses Timken tapered wheel bearings. Seen below, along with the exploded drawing showing how they go together with an axle adapter spacer on each side of the wheel. These bearings need to be packed with grease before being assembled into the wheel. I don't have any aviation grease, and I don't have a bearing-grease-packer tool either, so this is as far as I can go right now. This will have to wait.

May 15, 2012

I'm glad I waited and didn't install those bearings. While searching for a good place to find a grease-packing tool and the right kind of aviation grease, I read more and studied up on issues with the nosewheel. It seems people have been having trouble with this setup. Problems like nosewheel shimmy, excessive drag or friction on the bearings, and so on. It seems to be caused by these roller bearings being "sticky" in spots as they rotate around. Or, not being tightened just right as you press the bearings into the wheel. There's no solid spacer in the middle, between the two bearings, so it's too easy to overtighten, or not tighten them enough. It's old-school technology. It works, as it has for decades, if done right. But there are better solutions now. I'm learning more and more that general aviation is very slow to catch on to new improvements. A lot of things are done, apparently, just because "that's the way it's always been done". This is what I love so much about experimental aviation. You don't have to wait for a general consensus or a TSO before you can forge ahead with something better. So I read about a nosewheel modification in the VAF forums, and looked into it. Take a few moments and read this! Then make up your own mind.

Nosewheel Modification Thread on VAF

The company doing this modification is Anti-Splat Aero. I have no interest in this company, other than being a happy customer. They do a phenomenal job of modifying the nosewheel and installing new, permanent ball bearings. They also precision balance everything. Rather than go into a lot of detail here explaining why I'm so excited about this, take a minute and watch this YouTube video clip. It explains it all:

Nosewheel Bearing Modification

Here's one more video clip, showing the behavior of the nose gear leg, Before-and-After the wheel bearing modification. I should mention, the airplane you see in this video was built and is owned and flown by a very good friend of mine, Mike Rhodes. It's nice to see this documentation from someone I know personally. He's a great guy, and he takes his safety very seriously. Notice the landing before the modification, how the nosewheel gear leg bucks fore-and-aft, as the wheel bearings stick in spots as the wheel rotates. This solves all of that!

Before-and-After Landings

Okay, so with all of that overwhelming evidence under my belt, I boxed up my nosewheel and sent it off to Anti-Splat Aero. Turnaround time was real good, it came right back to me after a week or so. Meanwhile, I went to work on the brackets that will hold the wheel pant on. These guys need a lot of deburring and care. I'm getting tired of deburring aluminum parts, particularly ones like this that take a lot of hand work and time. But happily, these are among the last in the kit! Also, I went ahead and drilled the holes for the platenuts. After priming was finished, I riveted them on. Here they are, all set to go:

Then I did a test assembly on the bench, with all the parts. The design and engineering of this whole thing is quite impressive. I particularly like the stops (can't see them in this pic) on top of the fork that limit the travel of the wheel from side-to-side. Now... where's that wheel?

Here's my wheel, after getting it back from ASA. The mod is complete, and this wheel spins freely on the bench, almost frictionless, just sitting on the center spacer. Nice! I got out my torque wrench to double-check the torque on the bolts holding the wheel together. It's good to go! In addition to the new bearings, they have precision-balanced my tire/wheel assembly, and trued the tire. See the video above, you'll understand what I mean.

Next, I got to looking at the nosewheel fork. As it comes from Vans, it's a pretty nice piece of work, but a little rough around the edges. So I took some time to deburr it and clean it up. This turned into quite a job, because I didn't know where to quit. So I just kept going. I decided that it should be primed and painted. Why not? This piece of the aircraft will see a lot of dirt, debris, water, and who knows what else, so it should be primed and painted. That lightening hole that you see below on the left, should also be sealed, to prevent water from seeping down in between the two layers of aluminum and causing corrosion. In this picture, I have all the deburring and cleanup finished, and I'm masking it off for primer, blue tape wads to protect the threaded bolt holes. I'm using my heavy-duty 2-part epoxy primer for this job.

June 18, 2012

Days later, after priming, lots of curing time, and several coats of Rustoleum white paint, here's my finished fork, ready to go. You can see the sealed lightening hole on the left. I'm very confident now about this thing lasting a very long time. Looks good, too! It more or less matches the powdercoat on the gear leg.

The nosewheel assembly all put together. Love it! I still can't call it finished, though, because I still don't have any grease! Turns out, the housing around the gear leg is supposed to be filled with grease. You can see the little grease zerk sticking out on the front side. I'll get to this soon enough. I'm not nearly ready to put the plane on her gear anyway.

Before mounting this on the fuselage, I still need to do the "pull test" discussed in the plans, and set the correct tension by tightening the big nut on the bottom. Then the gear leg gets drilled for a cotter pin. And of course, there's the gear leg fairing and wheel pant. I'll do that later, when I get deeper into all the fiberglass work.

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