Tuesday, November 15, 2011

I have a new set of wheels!

Click on image to enlarge

It's a big moment when you get to sit in your creation and and make engine noises! But let's back up and see how I got here.

Once the gear was in place, it was time to assemble the wheels, axles, brakes and wheel pant bracket. I bought everything shown in the pictures below from Great Plains Aircraft Supply. I had drilled the 4 mounting holes months ago. The caliper housing comes to you fresh from the casting mold and needs to be "machined" to allow the calipers to fit inside snugly, but able to slide side to side nicely with out binding. You just use a combination of files and sanding tubes to slowly remove just the right amount of material to get the fit you want.

My axles had a "knob" on the back side of the mounting plate the same diameter as the axle. This is used in other installations, but not on the CX4. You have to grind this "knob" off to make the back side of the axle mounting plate completely flush. I didn't take a photo of this, but you'll figure it out if your axles come with the "knob".

There is a lot of assembly and dis-assembly in this process. You have to create a spacer to keep the wheel the correct distance away from the mounting bolts so as not to rub them on the brake disk. I used a piece of PVC tubing to cut a sample spacer until I found the distance I liked. My spacers were 1.75" long and I made them from .759" ID 4130 steel tubing. I would say this gave me a clearance of approximately 1/8".

Once you have everything the way you want them, you disassemble everything so you can pack the wheel bearings with grease. When you are done with that, you reassemble everything and mark a dot on the axle threads where you want to drill a cotter pin hole to hold the castle nut in place. I was told to only hand tighten the castle nut. Over tightening doesn't allow the wheel to rotate freely.

Also in the photos you can see the piece of aluminum where the wheel pants will be attached later. I used the pattern from the plans and found I had to modify them slightly to fit around my brake assembly. No big deal though.

Next I finished installing the tail wheel. When you tighten the forward bolt it will dent the bottom fuselage skin slightly. This is normal according to Dave Thatcher. I spent an afternoon trying to figure a way to avoid the dent, but the solution eluded me. Mine will have the dent like Dave's does. It is so minor that when you turn it over you don't know it's there.

Now it was time to turn it over! My son was the first to sit in it and he liked it. Then it was my turn. Here is where I get to caution the rest of you. It is best not to put too much weight on the seat area until you have attached the side panels. Why you ask? Because when I stepped on to the spar with one foot I heard a loud bang! I took my foot off and looked around and everything seemed to be in place. So I tried again. This time when I place my second foot on the spar I heard another loud bang! I step off and looked around. I still didn't see anything wrong. So I tried again to get in and this time there were no annoying sounds, but when I sat down and look forward, I could see that the single rivet at the top of each F5 bulkhead had popped free from the top longeron. I decided I needed to go on a diet.

I got out and found my two long wood clamps and pulled the lower and upper longerons together and drilled out and replaced the two rivets. I used longer rivets as well. I'll have to wait until the side skins have been installed to make engine noises again.

I have started installing the forward floor ribs so that will be my next update.

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