My Wooden Airplane
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2/6/2012 - 2/8/2012

Attach Rear Spar to Fuselage

So, I went to go drill the holes for mounting the rear spar attachment brackets, and realized that there's nothing to really anchor the bolts to. The space between the gussets is empty!
I went back and checked the plans, and it doesn't look like I forgot anything. So, I made some blocks to fit between the gussets and give the attachment bolts something to hold on to.
(This is a picture of the empty space, just forward of the main fuselage bulkhead.
I'll post another picture with the blocks later.)

Also, since the bottom of the wing is not flat, I had to make this jig. The top of the jig exactly fits the underside of the wing, and the bottom of the jig is exactly parallel with the chord line. This way, I can accurately set the wing angle of incidence to 4 degrees.

Here's how the rear spar attaches to the fuselage. I first had to make sure the wing "sweep" was set to 0 degrees. Then I clamped the brackets to both the spar and the fuselage and drilled (one at a time) the 5/16 holes that pass through the rear spar. This meant the sweep was now "fixed". Next, I used the jig and made sure the angle of incidence was exactly 4 degrees positive and drilled the three 1/4 holes (from the inside) through each of the brackets. That takes care of the wing root!

For completeness, here's a close-up of the front spar attachment:

Total Time: 6.5 hrs.