When the Bede BD-4 airplane was first designed, in 1968, the plans called for a bench seat in the front. I remember bench seats; my first car (a 1964 Dodge Dart) had a bench seat. Despite my fond memories of my Dodge Dart, I do not want a bench seat in my 21st century airplane so I am custom fitting a pair of individual front seats.
I got a couple of “really special” seats, and two sets of seat tracks, from a salvage yard.
It may shock you to learn this but I have to confess: The first thing I did was strip the seats to the steel frames.
When I started to clean the crud off of the seat tracks, I learned about intergranular corrosion. The tracks that I got were complete trash. There was corrosion within the crystalline structure of the metal. Here is a photo and do click on this so you can see the enlarged picture; it’s amazing.
Needless to say, I got four replacement tracks which are free of corrosion.
The tracks for these seats are aluminum. Alone, they are not strong enough to support the weight of the seats and people; they need to be mounted on a rigid surface. The Bede BD-4C floor is not designed to have seat tracks on it. For one thing, the floor is not flat; there is a box, 6 x 4.5 inches, which carries the loads for the main landing gear, across the floor. The rest of the floor is a single sheet of .020 inch thick aluminum. The original bench seat is designed to be attached to the C-channels which form the sides of the fuselage; it then spans the whole fuselage without touching the floor.
It took several evenings of planning and several more of drawing to come up with supports for the seat tracks. My supports will bolt to the top of the main landing gear box at the back and to the C-channels of the fuselage at the front. Here are the drawings as PDF files.
front seat track support front view.pdf
front seat track support top view.pdf
Each aluminum seat track will be riveted to a pair of .75 x .75 x .049 inch square 4130 steel tubes. The back ends of the tubes, under the people’s butts, are on top of the main landing gear box so that box will carry most of the weight. The front of the square tubes will be supported by a tube running across the front of the fuselage, a design I came up with by modifying the front tube of the original Bede BD-4C front seat.
Now that everything is planned, I am cutting steel. Here is a photo of one end of the tube that will support the fronts of the tracks, along with the components of the bracket.
After working on the round tubing, I fabricated the plates which bolt to the top of the main landing gear box. The square tubes to which the seat tracks get riveted will be welded to these plate. Here is a photo of the four plates on the pilot’s side of the plane.
The blue lines show where the seat tracks will be.
Looks good. My only concern is the seat height as the roof comes very quickly. Are you going to be about the same as the plans from the floor?
I will be cutting the “legs” of the seats down quite a bit. I should end up sitting just a few inches higher than the factory seats would have had me.
Hi Art, I see that you bought the exact same seats as I did. The frames can be cut down enough that the seats will be only slightly higher than the original Bede design. The front is limited by the pin locking system but the rear can be cut down very short. I have mine almost ready to got to the welder. I will email you the photos. Good work as usual.
Cheers, Mike