Aligning the Fuselage


By now it was mid July, 1998 and Hudco Industries still had not shipped my epoxy.  Looking to keep busy, and full of new-builder enthusiasm, I decided to continue working out of sequence and tackle the fuselage alignment.

The SQ2000 fuselage comes in two pieces--left and right halves--which makes perfect sense since it's built in a mold.   The Velocity fuselage is also a two-piece affair, but I believe theirs is split horizontally, forming an upper and lower half.  Does one design have an advantage over the other?  Hard to say for sure, but it seems to me that the highest stresses will be travelling down the centerline of the fuselage (butt line 0), which is precisely where I was expected to layup a complex joint.  I'll have to be very cautious with that joint to make sure everything comes out perfect.

The fuselage halves arrived from the factory bonded together with structural adhesive.  The manual is very clear to point out two things:

  1. It is critical that the two fuselage halves be in perfect alignment.

  2. The factory doesn't do this before they bond the halves together.

To the casual eye, the two halves looks pretty well aligned, and indeed they are.  But they weren't perfect: off by about 0.125" I'd say.  It's too bad the factory didn't take a few extra minutes to do the alignment, because it would save the builder several hours.

The first step was to break the blobs of structural adhesive (dark grey circles visible on the flange (mohawk)).  A hammer and chisel worked pretty well, although I did delaminate a few plies here and there.  Not to worry though, the flange gets cut off eventually.
Once all the bonds were broken, I had a little help to remove one half of the fuselage (it's not heavy, but kind of big for one person to handle) and set it aside.  You can see the grey adhesive blobs pretty well in this shot.
Next I took my trusty angled grinder and ground off the remaining adhesive.  This was pretty tough stuff.  I also sanded away any loose plies that my chisel victimized.  This exercise was repeated for the other fuselage half, of course.

Side note 1: this was about the point my neighbor came down and said "What the hell is all that noise about?"
Side note 2: Are we taking note of all my personal safety gear?   Gloves, dust mask, and safety glasses.  OSHA would be proud.

With a little help again, the halves were once again mated up, and carefully aligned.  There are several lines molded into the fuselage to assist with the fore/aft alignment, but nothing for vertical alignment... you just have to go by sight and feel.  Once I was satisfied, I drilled holes through the flange, installed fasteners, and just be safe, hot-glued the flanges together.  And no, I don't wear suspenders with my belt.

By the way, special thanks to my Mom for taking the photos (featuring me) and helping me move around the fuselage pieces.   She was passing through Seattle that weekend on her way from California to Montana and I didn't hesitate putting her to work (payback for all the dishes she made me wash as a kid).


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