I think the decision of what kind of seat is every bit as important a decision as to what resin or wood we use in our airplanes. I would say that there is little argument as to the simplicity of the stock sling seat but if you are going beyond that then it should require some real thought especially when you consider the possibility of having a real bad day and then that seat may be the only thing between you and concrete.
I have resized and attached a photo of my two seat designs that I came up with. The first one is the grey composite seat. Made by just cutting and fitting foam between the spars all the way down to the bottom of the fuselage with cutouts for the cross members of the fuselage floor so the entire seat bears on the spars and bottom skin. Since it is solid foam I liked the idea that should I have that bad day the glass would probably fail pretty quickly but the foam would continue to absorb a load assuming it stays in place. I am 6'-5" and I have already deepened my fuselage to get the required headroom that I am going to need while wearing a headset . Even by doing this I had to cut down the depth of the seat as much as possible to get my butt as close to the bottom as I could. By doing this I effectively destroyed the ability of my seat to take any real load. As it loads up it will "form" itself to the available area between and over the spars. As the load increases the bottom of the fuselage is going to flex and the only thing that will hold the seat is the spars. Each side of the seat becomes a shear web at this point but because of the depth of the seat its load carrying ability is zilch almost regardless of how thick I make them. And since most of the load of my reclined body will be on the aft portion of the seat this is even worse. Now look at the aluminum version and remember this is really all because of my height. By using a 1/8" sheet on the bottom I can get my butt as close as I want it to be to the bottom of the fuselage. I then used the same thickness of sheet to make 2" deep sheer webs on each side of the seat. These span the full length from spar cap to spar cap and then over the edges of both. The bottom has an "H" pattern of 1" x 1" x 1/8" angles that span from sheer web to sheer web and the cutout for the stick is lined in the same material. Also by bending the aft part of the seat from the bottom slope to the horizontal I create additional stiffness. The back of the seat is the same back as used on the composite seat and is hinged for access behind them. Believe it or not there is not much if any difference in weight between the two once the lightening holes are cut. Both versions use the same cushions so it is fairly comfortable but the load carrying capabilities are miles apart. And if you think this welding is bad you should have seen the intake manifold on the old Subaru, downright breathtaking. Stephen Teate Paradise, Texas The information in this email is confidential and may be legally privileged. If you are not an intended recipient, you should delete this message. Access to this email by anyone else is unauthorized, and any disclosure, copying, distribution or action taken or omitted in reliance on it is prohibited and may be unlawful.
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