Warped minds think alike
Dan,
About 3 years ago, I did a modified version of what you have done. My original intent was to use the .020" thick 2024-T3 ramp as supplied by Vans. However, after reading about cracking problems experienced by other 8 and particularly 8A fliers, I wanted to improve the rigidity of the original Vans ramp design. (My 8A project is an old pre-punched, not match hole model) Van originally intended to make the exhaust ramp on the 8/8A models movable, sort of an adjustable cowl vent. They scrapped that idea but left the basic design. (Perhaps to allow an ambitious builder to make a movable ramp??) I decided to move the ramp doublers to the inner floor ribs on my 8A. I also bent up an angle to replace the hinge at the rear.
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The center section of the 3 piece cross braces gets riveted to the top side of the ramp. The center section of the cross braces sits below the stubs on the sides. Two #8 flush screws (one on each side) secures the 3 pieces of the cross brace together.
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The flat piece at the front between the inner floor ribs is a shim. This shim keeps the front of the ramp even. Without it, there would be two bulges at the edges, due to the ramp contacting the upper flanges of the inner floor ribs.
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I later decided to replace the original, aluminum ramp with a .016" thick ramp made of half hard stainless steel. I was concerned about possible exhaust failure or cracks allowing a flame to blast directly onto the aluminum ramp.
After I had riveted everything but the ramp into place, I decided to switch from riveting the ramp in, to using flush screws and dimpled nut plates. Vans mentions in the instructions that the area between the ramp and floor is a potentially high corrosion area, due to it's exposure to exhaust fumes. I had etched, Alodined, epoxy primed and even finish painted the area to prevent this. However, making the ramp removable allows me to inspect the high corrosion area during my condition inspections. I used the screws, nut plates, trim washers and NeverSeize (so I wouldn't scratch the paint) to create the dimples into the angles which were now firmly riveted to the inner floor ramps.
Those of you who might choose to do this now, will be able to simply dimple these parts prior to riveting them on!
I also coated this area with thinned out ProSeal to keep the exhaust gases from working between the angles and the ribs.
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The photo above also shows one of the cross wise stub angles. These stub angles are actually riveted in place. The #8 flush screw is actually for retaining the stainless steel ramp. If I had decided to use nut plates and screws from the beginning, I could have simplified my support angle design.
This system gives the ramp excellent support. I never posted this sooner, because I didn't figure out how to insert photos till 2 weeks ago. I apologize for the grainy top 3 photos. They were taken with a disposable camera. That was before I broke down and purchased a digital model.
Charlie Kuss