The FAA likes to see a few pictures of the builder actually working on the airplane to prove he/she actually built it, so the above is my "proof" picture so to speak :>)
Rear Slides
The aft end of the seat has some 1/2" tube "stubs" sticking out from the
sides. These stubs slide inside some "U" shaped channels that are welded
to the fuselage diagonals between stations "C" and "D". I made the
seat "U" channels out of some 4130 square tubing 3/4" x .058" thick. One
face of the square tubing was cut off making a "U" shaped channel. Here
I am cutting the square tubing using a die grinder with a cut-off wheel:
The FAA likes to see a few pictures of the builder actually working on the
airplane to prove he/she actually built it, so the above is my "proof" picture
so to speak :>)
Here is the channel piece after the initial cutting:
The extra material was then filed until it was smooth with the sides.
These "U" channels need some ends to act as a stop to prevent the seat from
sliding off the end and falling out of the channel. To make the ends,
I just trimmed one end of the "U" channel as shown below, then bent it over
and welded it:
The tab was then bent over with a hammer as shown below:
This was then welded shut. The front end was closed in the same manner
but a 3/4" long notch was created in the top edge to allow for a way
to get the seats in and out.
Now its time to weld the front locking mechanism (seat control unit) to the cross tube at station C/S. You want the seat in the proper position, centered in the opening, square to the sides, level side-to-side, and tilted fore and aft to the proper angle. Remember, the aft end of the seat has some 1/2" stubs that will slide in "U" channels to be welded to the diagonal tubes of the fuselage. Therefore, tilt the seat enough that the bottom of the stubs align with and center on the diagonal tubes that run from station C/S to station D..
The front locking mechanism was attached to the bottom seat frame and locked
in place with the pin. The seat was then clamped and braced into position
in the fuselage, again making sure that it was centered left and right. It
was clamped at the aft end as well making sure the rear slide stubs were
centered on the diagonal tubes (where the rear "U" channels will be). With
everything in place and the seat at the correct angle, the front control
piece was tack welded to the cross tube at station "C" as shown below:
The aft "U" channels were then fitted and tack welded on one end only. Now the seat was slid back and forth to assure proper alignment of the rear channels. If there is any binding, the channels can be tilted slightly until the seat slides freely. Once they were properly positioned, the "U" channels were welded in place using 1" long skip welds to prevent distortion. The channels should be skip welded top and bottom to the diagonal tubes.
Now go back and finish weld the front locking mechanism.
Again, here is all of the seat slides and locking mechanism (front seat controls)
in place:
The 1/8" pad is there because my seats ended up slanted slightly. To get them level, I needed a spacer there.
Seat Springs
There are a couple ways to prepare the seat frames for the foam and upholstery. The original prototypes have "No Sag Zig/Zag" springs. Some folks are building aluminum pans and some are using heaviest weight Poly fiber aircraft covering fabric. Some are building plywood seat bottoms.
I chose to go with the no sag zig/zag springs springs like on the prototypes. They seem to be one of the lightest and most comfortable ways to go and are fairly inexpensive.
The Zig-Zag seat springs were installed by drilling holes in the frame. I
found that it helps to take a punch and hammer it at an angle as shown below
to pry out one side of the hole. This makes inserting the spring a whole
lot easier:
Springs are then cut to the correct length to make them arc about 1" high in the middle.
Here are the springs installed in the holes on 3" centers:
As you can see, the springs were cut and then bent on the ends to make them hook back out of the hole. This keeps them level.
Click here to go to Front Seats page 3