Saturday, August 31, 2013

Ch 8.6: Outside Seat Belt Attachments

Next is the work to install the outside seat belt attach points for the front and back seats.

The outside attachments involve a birch reinforcement piece cut to fit the angle of the fuselage sides and bottom at the lower longeron. These are floxed in and glassed over...2 fwd, 2 aft.

On top of the birch supports are mounted 2" wide aluminum angle brackets that will be used to connect the seat belt.  These are cut from a piece of AL angle, holes drilled, and then they are used as templates to drill the holes through the birch support and the fuselage for the mounting bolts.

No Step.  Normally you would also install an exterior step at the same time that matches up with the pilots left seat belt attach point,,,but on the exterior of course.  As of right now, I've decided not to install a step.  I'm tentatively planning to modify the plane with extended strakes (aka Cozy Girl Strakes) to provide more elbow/storage room inside and if I do that, the step would be in the wrong place.  If I do anything, I might consider a retractable step like Marc Z installed.

Installed birch support, glassed & drillled.
Ready to install aluminum bracket.
Deviation:  As with a few other builders, the bolts to attach the brackets were not quite long enough.  I don't know if this is because some of us aren't counterboring the outside of the longeron deep enough or what, but I didn't want to go too far.  Your mileage may vary.  Marc Z. recommended in an archive email not to counterbore the hole more than approx halfway through the thickness of the longeron.  Well for me, that meant getting bolts that were just a bit longer.  I ended up using -AN-525-416-"18" instead of -"16".

After cleaning the brackets with Alumiprep and Alodining them for corrosion protection, I floxed them to the hardpoints and installed the bolts.

UPDATE (08/31/13):  I ended up using one set of "-16" bolts in the front passenger side.  The -"18" was a little long.  I guess I counterbored that side a little deeper than planned.


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