November 11, 2015

Time for my next catch-up post:  Mounting the wings.  I did this step back in August so it is a bit late of a posting.  This was a rather stressful step in the construction process since the wings had never been mounted to the fuselage.  With the wings all finished and the fuselage mostly complete it was pretty important that the wings fit.  I needed to fit the wings so I could run the cables and position the pulleys in the fuselage.  Prior to mounting the wings, I decided to forego building my lift struts and decided to purchase a set of PA-12 sealed struts from Univair.  I made the decision on the need to move the project forward.  I have a nice set of used PA-12 but I was not able to fully verify the inside condition so I purchased a new set.  Time to mount the wings.  

I bought a drywall lift from Harbor Freight to use to lift and position the wings.  Note here; I am only able to mount one wing at a time in my shop so the lift will come in handy each time I have to do this step.  

First was getting everything into position.  With the fuselage turned and the shop cleared some the lift was in position and everything was ready.  


The tail needed to be placed level to make it easier to fit the wing using the drywall lift.  The lift was set level so raising the tail got everything into alignment.  

Next, I place the lift ready to hold the wing in place ready for lifting into place.  Some help will be needed here; I did the wing with just one helper; second wing just with my wife.

Ready for the wing.  First step is placing the wing on the lift.  It took a little movement left and right to get the wing to balance on the lift.  Once centered it was ready to lift.

Centering the wing on the lift .......

Raising the wing with the lift.  My friend Eli held the wing tip and steadied the wing.

Checking the position of the wing at the wing mounting points on the fuselage.

Moving the wing into position for the wing bolts.  I used under size bolts just to get the wing secure and in place.

After the first bolt was in place the wing had to be rotated a bit to align the second bolt.  A second set of hands helped with the alignment.  

The struts were than put in place and ....... it all fits!  I used the old struts with undersize bolts just to get everything up.  

It's starting to look like an airplane!  Next step was to mount the new struts.  There was some interference between the strut and the underside of the spar.  I already removed a bit under the strut lift attach point on the other wing during the build.  I had to remove about 3/8" at the point under the lift strut.  I believe the plans are in error and the lift strut attach fittings on the wing should be set lower by 3/16".  I would recommend having the lift struts before drilling the location of the attach fitting holes on the spar to make sure you have enough space between the end of the lift strut and spar.  I did consult with an Aero engineer about removing the 3/8" from the spar.  He directed me to remove the wood over a 4" area in a wave pattern.  Turns out it reduced the strength of the spar from 16g's at 240mph to 12g's at 240mph; not an issue but better to be sure.

Here is a picture of the interference between the strut and the spar.  I carefully used a flat chisel in a scraping motion to remove the little needed to clear the spar.

Next step; running the cables for the ailerons and the flaps.

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© Marty Feehan 2015