[Hindsight]

I was under the impression that the headrests are not designed for head protection (roll bar equivalent). I know of many Cozy flyers using auto headrests or none at all - for one reason or another. So, I decided to make a set of smaller and light weight headrests in place of the original set.

Here's a picture of the pilot's headrest glassed onto the canopy frame per Plan. Note the extra storage space I made available for in-flight access.

You can see more pictures of my headrest in Chapter 25 Section 3A (finishing).

Once the micro on the corner was cured, I proceeded to cut out the square hard points, fit them into the foam per instruction. At this point of construction, they should be easy for all of us builders. I went ahead and glassed the hard points at this time because of the easy access compared to plan instruction to install the glass after the shoulder rest is installed onto the front seat back. Here's a picture of my shoulder rest after the hard points are glassed in.

Important Note:

I put a sheet of plastic on the under side of the foam while installing the square hard points such that the flox (that oozed out) would not stick to the table top. You can imagine the fun you'll have digging the shoulder rest free .

The hinges were easier to install than it sounds. The key is to line it up perfectly before floxing them in place. I did not use the 4' level (per instruction)... instead, I mounted a long T-square against F22 and then slid the long edge (left & right) parallel to the upper longeron for a satisfactory position. This allows me to find a good place for the bolts to go through the upper longerons AND that the hinges will be parallel to the centerline of the plane.    

I then slid the piano hinge plate under the T-square with its hinges butt along the straight edge. After I confirmed its positions per instruction, I put a temporary length of piano hinge in between the permanent ones and slid a long pin through all three hinges - just for alignment verification. I then applied flox under the permanent hinges and clamped them down for cure (as shown).

To avoid flox getting onto the hinges, I taped them down with packing tape. As I found out later, the packing tape left a real sticky residue on the metal surfaces. I tried removing them with razor blade, alcohol, acetone and vinegar no luck. Finally I tried paint thinner and it worked wonderfully. It removed all the glue residue ... including the markings on the piano hinges .

Since the hinges are straight and the upper longerons are curved, the bolt hole positions are not as straight forward. I was debating if they should line up with the hinges or line up along the center line of the longerons. Eventually, I drew two intersecting lines - one along the center of the hinge plate  and the other along the center of the longeron. I drilled the bolt holes somewhere in between the 2 lines. They turned out OK.

After the holes were drilled, I bought a 1/2" counterbore bit from the internet (that can mount onto a 1/4" drill bit). I used it to put the counterbores for the anchor bolts. Counterbore for the front right seat was straight forward because the lower longeron was close to the surface. I hit wood quickly and was able to put a nice flat surface for seating the anchor bolt head.

[Hindsight] The AN4 bolts called out in the Plans may not be long enough. I did not find this out until I was mounting my seat belts - after Chapter 25 (filled, sand and primed). The protruding thread (between .235" to .335") was not long enough to accommodate the .125" thick bracket, the squeezed nut (.214" thick), plus two threads (.071"). Drilling them back out is out of the question at that point. My solution is discussed below...

While waiting for the delivery of the new bolts and screws, I decided to glass in the shoulder rest. I made a glass tape for the inside surface of the shoulder rest but forgot to leave the outside edges of the glass free of epoxy (per plan). I waited for only one hour (for the epoxy to form) before I attached it onto the front seat back. Hopefully, the glass will not detach from the foam. Guess I'll find out when installing the shoulder belt bolts... I left it to cure overnight.

I removed all the peel ply (the next day) and rounded off the front edge of the shoulder rest in preparation for glassing the top layers. I just set up the router and made 3/16" radius along the front edge - remember Chapter 3 (education)? BTW, don't forget the four (4) strips of 3 plies over the shoulder hard points - they are in fine print. I got a few long bubble strips along the back side of the enforcement strips when wrapping around the back edge of the seat. I should have rounded off the back edge of the seat while I was at it on the front but decided against it because it wasn't called out in the plans. Now I have to drill them out and fill them with epoxy. Live and learn....  

First, I made the 4 nut plates per plan. I have to refer back to Chapter 6 and see how I did it for the fuel selector. Somehow, I forgot to take pictures of the nut plates. Once completed, I projected the center lines of the 4 hard points down the front face of the shoulder rest. If you look close at the picture (left), you should be able to make out the penciled center line. Based on the thickness of the foam and glass, I can establish the position of the horizontal slot (I needed to cut) for the nut plate to slide into. Directly under the horizontal line I marked a center point for a 3/8" hole.

Starting with the hand drill, I drilled the 4 (3/8") holes on the front face of the shoulder rest. Then I used a jig saw and re-shaped the round holes into square holes. Right along the top edges of the square holes, I cut out the 3/4" horizontal slots to accommodate the aluminum plates (that the nuts are riveted onto). I re-checked the hole locations against the center of the hard points to make sure they are still aligned. Then I drilled the 1/4" holes through the center of the 4 hard points. Surprisingly, the drilling and shaping of the holes were not as difficult nor time consuming as I anticipated. Once completed, I slipped the nut plates through the slots while peeking through the anchor holes from the top. Magically, they lined up perfectly...

Took a bit of pondering before I figured out how to establish the bottom profile of the rear heat duct. I first laid a laser along the sides of the forward heat duct and projected it rearwards onto the landing gear bulkhead. I marked the laser lines with a pencil onto the surface of the fuselage. These pencil lines established the 'footprint' for the rear heat duct.

I used my long T-square/ruler and stuck one end of the T into the hole above the front heat duct. With the edge of the T resting on top of the front heat duct, I now have established the slop of the heat duct (its supposed to be leveled horizontally) - while the remaining leg of the T projected the slope outward for the rear heat duct. I extended the T by clamping a straight edge to it (the red level was just handy at the moment). Then I laid a measuring tape along the pencil lines. With a ruler, I recorded the height between the bottom edge of the T and the fuselage surface (at the pencil mark). I repeated this measurement at 1" intervals - totaling 28 points (remember, the rear heat duct is suppose to 28 1/8" per plan?).

I took those dimensions and re-created the profile on a piece of paper. Connected  the dots with my un-official giant French curve (a long strip of Formica). Then I placed the paper on top of the foam and transferred the profile with my tracing wheel. Trimmed the foam sides with a blade and floxed them together - forming the rear heat duct. Then I trial fit it in place and with minor shaping, I was able to make it from good to nice fit!

When I mounted the 3/8" tubing onto the forward heat duct in Chapter 6, I prepared the foam (where the tubing sits) by wrapping a piece of sand paper around a wood dowel and sanded away. This time, I just took a 3/8" drill bit, mount it on my drill press and turned it on. I pre-marked the tube location on the rear heat duct, then pressed it against the drill bit. I ended up with a nice curvature that hugs the 3/8" tubing perfectly. It took about 2 minutes for the entire operation.

I floxed the tubing in place making sure I have a long shallow sloped fillet along the sides of the tubing (I remembered the difficulty I had glassing over it the last time).  I then glassed the tubing in place per plan. Note the smooth transition along the sides of the tubing this time.