Correct Seats in a 415C
I will try to attach a couple of pictures to this e-mail which should give you a better idea of what is involved.The pictures have some of the pieces used and an Airtex seat and back installed in a Coupe. The original seats were horsehair filled cushions which were placed in the seat pan. The original seat back (which I have not seen) was laced to the seat frame with cotton cord. The seat belts were fastened to small steel triangles, welded to hold them together, which were placed through a hole in a steel fitting on the bottom of the seat back frame. The steel fitting had a tongue that went through the seat back and was fastened to a larger triangle. The larger triangle had a steel rod fastened to the rear which hooked up to fittings in the bottom of the fuselage.
Airtex has come up with a replacement seat that is one piece instead of the two cushions. This generally works out fine unless you are over 6 feet tall. The one piece cushion seems to remove about 2 inches of head room, which makes it difficult for tall people to wear head sets and not bump their head when the window is closed. Some people have placed plywood under the single piece cushion, which I believe causes undue strain on the seat pan.
The construction of the seat frame was of fairly light aluminum and had a tendency to crack, especially when used without all the fasteners in place. So you often find lots of repairs on/in the pieces. The seat pan was fastened to the seat back with three metal hinge pins, to the center section ribs with two screws (#8 I believe), and to the front spar with two #6 screws. The seat back was fastened at the top with two AN-3 bolts, and at the bottom, to the window shields, with two # 6 screws.
I realize this is probably much more than you were looking for, but I hope it helps.
Regards Lynn Nelsen