Wednesday, March 4, 2015

Ch 9.3: Main Gear Installation (1 of 4)

Gett'in Jiggy With It.  

As bought, the strut doesn't have any way to attach it to the fuselage so you have to provide those by way of fabricating attachment tabs.

Note to future builders...Don't rush these steps.  Take your time, check and recheck measurements. The more accurate you are on each of these steps, the easier job you'll have installing the strut into the fuselage and having everything line up with minimal adjustment.  

The first step is to build the jig.  I built a perfectly vertical backboard and laid out the alignment marks that define the center line and location of the future attachment points.  A check of the FAQs indicated that it is likely that one attach point location would be slightly higher than the other just because the strut may not be perfect or you may have had some variation in the thickness of the previous 8-ply layups.  I had one side that was .1" higher.  The FAQs say to use the higher of the two and match them.  Now that the forward attach point located, I built the jig box per plans, bondo'd it to the strut, and transferred the points from the backboard to the jig..  This was pretty straight forward.   

Strut against backboard w/ Jig attached.
Profile of Jig and strut sweep angle.
Plumb bobs show the LE all lined
up on the table top.

With the jig built, I moved it to the work table and positioned it per the plans.  After some shimming and leveling, the strut is aligned such that the LE of the strut falls exactly 9.25" in front of the back edge of the jig.  This further aligns the strut and jig in such a way that all four attach points should be at the same distance above the table.  This then allows you to locate the rear attach points based on the measurements of the front points you already located.

Level Baby !

Complete setup, level both directions,
LE at the right spot, and braces to help  keep it there.

This all looked complicated at first but it's actually pretty simple and I think rather ingenious.  Now it's ready to build the attachment points.

Onward, cab

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