Fuel Tank Attach Brackets

Time: 8 Hours

After finishing the rear spar you have one task to complete before moving on to the fuel tank attached brackets. The fuselage bottom skin overlaps the wing by a few inches. The usual eventually get combined together with screws after the wings are attached for the final time. The wings skins add the holes drilled in them already but the fuselage skin does not. What you were supposed to do is mark all the holes on the wing skin with lines before attaching the wings so that you have a reference point and distance in order to drill the skin on the fuselage. However they make a cool drill jig that my buddy Glenn had so I borrowed it and made quick work of these holes. This tool basically as one side with a nipple that will identify the hole on the wing skin and sandwiches the fuselage skin between the tool so that you can drill the skin and it will match up perfectly. 

    
 I know that’s not the best description hopefully the pictures will help describe it better. So now when I remove the wings I will dimple the fuselage skin and put nutplates in the wing skin. With that tool I was able to get all these holes done really quick. From there you move on to the fuel tank attach brackets. When I built the fuel tanks I had put a bracket on each forward inboard corner that would eventually mate up with the brackets I need to make. The plans call for these brackets to be made out of U channel aluminum.  

 So I took the dimensions and measurements and marked them on the two pieces of U channel. 

    
   After four hours of drilling, cutting, grinding, sanding and filing I had the two final pieces. 
 This is where they will fit eventually.  

   As you can see that they don’t fit completely flush up against the fuselage, and flush against the tank bracket. Van’s says to hit them with the large hammer in a vice to bend them to get them to sit flush at both locations.  That is an understatement! These things are thick and not easily bent. It took me an hour to bend and manipulate the right side to get it to fit flush against the fuselage and the tank bracket. From there you clamp the brackets together with it tight against the fuselage and drill from inside the fuselage through the bracket. This is not an easy task as it’s pretty tight inside the fuselage. I started with a 12″ #30 drillbit from inside and finished with the  #12 drillbit in my angle drill from the outside. with the first hole drilled I put in AN 3–7 bolt in and tightened it down to hold it tight against the fuselage. I then drilled the second hole and repeated the steps to finish that bracket.  

  

  

 I moved on to the other side and finished it up a little quicker than the first as I had a little insight as to where to bend.  

 With both brackets secured to the fuselage I marked the brackets for the single AN4 bolt and drilled the hole.    

 So now all the wing attach points have been completed. This will no allow me to build and rig things like the aileron attachment, flap rigging and fuel line connections. 

 

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