Seat Foam and Brakes

Tabitha came out today and started working on the seat foam while I made some of the rigid brake lines.

Tabitha's Seat Foam

In this picture, it looks like Tabitha is explaining to me about how it is going to be. This is the bottom of a front seat cushion.


While she was working with the electric knife, I installed some nutplates in the firewall. For such a big sheet, the blind dimple die is really useful.
Blind Dimple

This is the tool for making dimples in the middle of a big sheet, such as the firewall. The dimple dies have a hole in the middle that is just big enough for a nail, which goes into a pop riveter.


It’s very important to stay focussed with this operation. The tool only requires a soft squeeze with the rivet setter. On one occasion I was thinking about something else, and gave it a full pull, promptly breaking the nail.

Since we deciced to go with a 3-inch bottom cushion instead of a 4-inch, we had some extra 1-inch foam left. My preference was to make the top of the seat flat to help make the covers easier to sew, but she wanted to go this route to make the seats more comfortable. To settle the dispute, she agreed to make a wedge so that we could compare the two configurations and see if the benefits would outweigh the costs.

Experimental Wedge

Tabitha makes an experimental 1-inch wedge.


I also decided to move the fitting in the firewall where the brake line comes through. The first one is too close to the brake pedals, and I’m concerned that it might limit brake travel if the pilot’s foot is high on the pedal. The first location was arbitrary, so it’s no trouble to move it. I’ll just need to come up with something else to put through that hole, or perhaps a patch. If I can end up with just one wrong hole in the firewall, I’ll certainly be happy.
Bad Brake Line Location

This is a bad place to bring the brake line through the firewall, especially without a 90-degree fitting.


Another Angle- Brake Line

As you can see, with a straight AN fitting, the tube sticks way out there. With the left rudder pedal all the way down, the brake pedal gets closer than I would like.


Here’s a good view of the seat foam, including the lumbar support. The white foam in the seat back is two layers of a more rigid foam, which will hopefully help provide good lumbar support. The Avipro fames actually have a pretty good lumbar support built in. You can also see the “wedge” proposal on the seat bottom.
Bearhawk Seat Cushion

Tabitha's Seat Cushion Proposal

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Hours Logged This Session: 7
Total Hours: 1883.75