Chapter 8

Chapter 8 - Head rests, heat-duct, seat belts and step

This chapter covers the making of the head-rests, the aft heat-duct, the attachements for the seat-belts and the steps.

The modifications I am doing will now result in alternative ways of doing some of the things. In this chapter I will probably skip the head-rests for now. The plans
canopy is side-hinged, while I will make a forward-hinged. That makes the attachement of the head-rests different. Some builders have even skipped the
head-rests completely! I will most probably make removable head-rests like in a car. The head-rests are neither structural nor made to protect from a roll-over. It's
just for resting the head :-).

The plans calls out for 4-point seat-belts. I have bought 5-points with a crotch-strap to prevent "submarining" in case of a crash. This calls out for me having to
make a 5th attachment-point for the crotch-strap.

I plan to paint the plane yellow, so I've decided to have yellow seat-belts. The upholstery will also be yellow in some way.

The step as called out in the plans are also obsolete when I makes the extended strakes. The step will be much to much aft. Instead I will
make retractable steps aligned with the intrument-panel, and one on each side. I plan to copy Wayne Hicks steps.

There are several solutions to the head-rests when I read through the builder-blogs. Some have used head-rests from cars, other
have designed their own, and some have even skipped them totally. I decided to build the plans head-rests, but soon realized
that they looked too weird for me. Some have pointed out that they would fit a conehead, but not a normal human beeing. I tend
to agree.... :-)

They are the same width and depth, but only 7" high and rounded. To get the glassed foam (glass on the inside) to
bend around the curved front and back I made several cuts in the foam. Then the foam easily followed the curve. I
floxed this and will fill the slits in the foam with flox prior to glassing the outside.

The shoulder-support is made as pr. plans except for the seatbelt-hardpoints. After advices from other
builders I expanded the spacing between the hardpoints to 11". Doing this I avoid making notches in the
head-rests and I also avoid to have the seat-belts lying into my neck. With my belts it's no danger that I will
slip out of them in a crash. In this picture I have epoxyed the plywood.

The nut-plates are riveted to pieces of thin aluminum. I alodined the aluminum and drilled some extra holes in the
plates to make the flox grip better to the plates. I will flox these to the underside of the plywood before I flox the
shoulder-brace to the seat-back later.

The shoulder-brace is glassed and cured. The final step is to add 3 reinforcing UNI-plies over each hardpoint
for the seatbelts. This is a step not mentioned in the plans, but found in the FAQ and recommended to add
strength since the forces here will be quite strong if an accident happens. It's a bit tricky to get the UNI to stick
when bendt around the seatback and down behind. I clamped a particle-board to the back after covering it with
saran-wrap, and weighed down some saran-wrapped wood-sticks on top. I got away with just a few
air-pockets which I will fill with epoxy later.

The candle-wax procedure was a success. I (carefully) drilled through the glass over the hole, then used a small
knife and a screwdriver to dig as much wax as possible out, the rest together with the little paper-ball was just
pushed down into the brace. Finally I used a 1/4" reamer to "touch-up" the nut.

The bracket is floxed in place and the screws are tightened. I recessed the heads in the fuselage,
actually counterboring through the glass on the outside until I reached the longerons. Filled the
outside hole with flox.
However - I bumped into a small problem in this step. The distance between the outer fuselage wall
and the top of the seat where the bracket are mounted was almost 1/2" higher than the plans! This
resulted in the screws beeing too short. I had to purchase new longer screws to solve this.
The reason for this error (minor!) is probably two things: I didn't remove enough foam when I
rounded the outer part of the fuselage. I could of course just drill a deeper recession from the
outside but I didnt quite fancy that idea compared to just adding longer screws.
The other reason was that instead of fiddling around with the plywood-hardpoint to get it lay dead
smooth on the fuselage-side, I just put a generous amount of flox under it, making the height a bit
higher. I didn't think about the screws at all... well, no big deal.
I ordered new screws from Wick's since ACS didn't have the right dimension. Wick's was extremely
quick and I got the screws sent from USA after only 4 days! Thumbs up!

Aft heat-duct

This is the "transition-piece" - the transition from the aft heat-duct to a tube that goes further back and to the
firewall. It is made from a piece of 1.5" urethane. It is square in one end and circular in the other - hence
"transition". The urethane is covered with some electrical tape as a release-agent, then covered with 2 BID
and wrapped in saran-wrap to hold the BID tight. After cure the urethane is carved out together with the tape
and I end up with a tube.