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Dave's Sonex Builders Log

Welcome to my builders log for Sonex S/N 767. It won't be as big as a real 767 but if you scale the speed I bet it will be almost as fast.

This website is to log my progress while building a Sonex airplane. I purchased the plans for Sonex S/N 767 and began construction around Christmas 2004. I would like to keep my costs down and am currently considering the AeroVee engine. I'm also building the Sonex with standard gear and a single centre stick.

Today I worked on some tooling to help with the final triming of the canopy. I found that the toughest part of fitting the canopy was pulling  it into position along the fuselage sides. So, I made up some pieces of MDF that I could clamp to the sides of the fuselage using ratchet straps. The MDF ends up flush with the upper longerons and provides a surface that I can clamp to. I plan to clamp some AL angles to the MDF to hold the canopy in place for the final fitting before I start drilling holes. I'm also hoping that I can drill the canopy while it is clamped in place. I know a lot of builders use a ratchet strap to pull the canopy down into place but I find this distorts the canopy so I really want to let it side in place and just pull in the portion that aligns with the upper longerons.

I continued to work on installing the tail wheel. I reinstalled the tail wheel mount and proceeded to install and torque the fasteners. I found that I needed an additional washer on each fastener to get the correct grip length.

I continued working on the main gear today. I removed the right hand axle from the gear leg and carefully marked the location for the cotter pin hole. I did this with the wheel and brake assembled to the axle and marked the location of the notch in the nut on the axle using a sharpie. The hydraulic brake drawings (SNX-L07) indicate that the hole for the cotter pin should be located after assembly. The SNX-L01 drawing shows this hole horizontal with respect to the axle assembly. I drilled the hole for the cotter pin and re-installed the axle stub on the gear leg. Next I greased the wheel bearings and installed the wheels. I left the cotter pins unbent in case I need to take the wheels off to work on the brakes.

I noticed that Sonex provides nuts to be used on the bolts that secure the brake discs to the wheel. I had originally used the incorrect nuts so I removed each nut and replaced it with the nut supplied by Sonex. Next, I spent some time dry fitting the bearings. This involved fitting the pistons into the half caliper. I used a bit of brake fluid to lubricate the o-ring and the pistons pushed in with a bit of force from my fingers. It was toughest to get the pistons past the initial tapper. Then the pistons when in fairly easily. 

With the brakes assembled I fint the wheels and marked the left side for the cotter pin. I then dismantled it all and drilled the cotter pin hole.

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Third times a charm?! I was still not happy with the fuel line routing/bending so I decided to try once more. I was very careful to avoid any uphill bends under the fuel tank. While the line runs downward on an angle when the fuselage is level, the line will move more towards the horizontal when the plane is in a steep climb. I had to put a slight upward bend in the portion under the tank but for the most part the joggle bend is horizontal. Forward of the firewall the line runs only down hill. This time I'm pretty happy with the outcome. 

I also notched the bracket for the gascolator so that the gascolator could be removed without removing the bracket once the fitting was installed. I installed the plug in the gascolator but I still need to use some lock wire on them and the cotter pin the fasteners.

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I worked on finishing the gascolator end of the fuel line. I started by shortening the line until it was the appropriate length to flare. Next I flared the line an checked the fit up. I'm not too happy with the routing inside the fuselage under the gas tank. I have a short segment that may be uphill when the plane is in a climb. I'd like to eliminate this if possible.

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