For years I have had the seats lowered by bolting them directly to the floor. I have never liked this approach for obvious mechanical reasons but also because it makes taing the seats out and reinstalling a PITA!!
Not having the tools to weld nor wanting to learn and do a sloppy job, I decided to take a different approach after I read about using rivnuts on the tunnel to avoid heating up the fuel lines. Thought I would share it with the community.
I am very familiar with composites and have built many many things out of Carbon Fiber (CF) for both extremely light and strong applications as well as structural members for experimental 200 mph aircraft, so I thought I'd try this approach.
The goal was to lower the seat rails about 1.5" and have them adjustable up to 2" further to the rear with 3 sets of mounting holes and floating captive nuts. I also wanted brackets that race seats brackets could be bolted to if someone wanted to.
To do the CF I made a mold by gluing two pieces of scrap Corian together that were about 4" wide and 24" long to make a 90 like an L bracket. The corian was then cleaned and waxed with Partal wax and then some release was put on.
I used some CF I had on hand and decided that I wanted a layup that was about 0.17" this (probably overkill, but the additional weight wouldn't be noticed), with some of the carbon on a 0/90 deg layup and some +/-45 deg. That way I would have good strength in all directions.
With the carbon I had this would take ~17 pieces stacked on each other. I started by wetting out the corian mold with West 205 and Slow hardener and then proceeded to put each layer in the mold being careful to throughly wet them and make sure the corner was pushed down (sorry no pics as my gloves have resin on them).
Once all the layers were applied, a layer of perf release film is applied and then some heavy breather cloth to soak up the excess resin. This assembly is put in a vacuum bag and a vacuum applied. The resin was allowed to cure for 24 hrs and then put in a home made "hot box" to allow it to post cure at about 160 deg F for another 8 hrs.
The result is a very stiff strong pat that I then trimmed from templates I made from poster board. Hard point were made by oversizing the mounting holes and filled with a splooge of resin, cabosil and flox, then the holes were re-drilled.
In the pictures the mount are temporarily held in place with sheet metal screws while I wait for the M8 rivnuts to get here. Along with the bolts, the rails will also be glued to the chassis which should make a joint stat is stronger than the CF.
For the seat mount nuts I will be using floating M6 nuts that I believe will be riveted in place (haven't found the nuts just yet, need to look at Aircraft Spruce catalog)
Terry
