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Fuel Strakes:


  

  The Lower Strake is bonded into place with the wing attached so that proper alignment can be achieved between the wing root and the outboard edge of the strake.


The gear leg cutout in the lower strake is curved and should be cut with more clearance on the rear edge to allow for air loads pushing the gear back during flight. Also allow for slightly larger tire size. There is nothing to be gained by being too tight here.

 

 

  The gear cutout flange was built to plans. This results in gear doors having nothing to close against. It is virtually impossible to stop the doors from hanging into the slipstream or from closing too much on one edge or another. A better solution would be to reverse the flange so that the doors close against a recessed edge, ensuring a smooth underside to the airflow. The strake skin is thicker than the door, which would allow placement of small neoprene rubber blocks around the periphery of the gear door flange for proper positioning of the gear doors when closed. The gear doors should not close directly on the flange in case water freezes the doors shut.

 

 

  Now is a good time to fit the gear doors if you are building to plans. You can easily reach over and draw the cut line from the inside of the gear well.


The tire was covered in 3/4-inch foam all around to give shape to a minimum volume gear well. This allows maximum use of the strake volume for fuel. The foam was covered with tape and then peel ply, before four plies of BID followed by more peel ply.



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  The gear well was not bonded to the strake at this point. The positive mold was destroyed to remove the gear well shell. We then used the inside of the shell as the mold for the left hand gear well.


Note the fan heater. We have five of these ceramic heaters. Invaluable for local use when working below 70 F. In this case the strake was covered with a tarp and allowed to cure overnight.

 

 

  The internal baffles were redesigned to maximize internal volume. The factory-supplied resin was used on these hence the brown color.


These were trial fitted many times to ensure a smooth transition between the strake top skin and the wing, rear of the spar carry through.

 

 

  A wing rib layout was used with each baffle bonded to the strake skins with two layers of BID tape in each corner. Special attention was given to the flanges to ensure a good fit with the top skin.


The rear baffle was omitted and so a half round pipe section was made and bonded to the leading edge of the strake. This has the dual purpose of reinforcing the leading edge and is also used as a duct, to carry the wiring to the strobe lights and antennae.

 

 

  The interior was painted with two layers of epoxy tank sealer . except at the contact points with the top strake skin. There is no going back at this stage. Make sure you have lots of small shot bags and that they will not slip off during the cure. We found areas of delamination inside the top skin, along the leading edge. These were bubbles of trapped air where the factory vacuum molding process had failed to pull an adequate vacuum. We drilled a series of holes three inches apart through the outer skin and injected a slurry of micro starting at a low point, Each hole was taped over before progressing to the next. A coin tap test shows all the void was filled.


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