Step 9.0, Installing the steps

On the tricycle gear version of an RV airplane, the RV7A in my case, the fuselage sits fairly high off of the ground.  A little bit too high to comfortably step up for ingress.  So the steps are added just behind the wing to permit a middle step between the ground and the top surface of the wing.

I didn't take any pictures of the steps before I drilled the flanges, but I wanted to include a shot here to show the whole step to put the following photos in context.  As a first step, (pun intended), I laid out the locations for the holes in the flange.  The flange sits on the outside of the skin and the pipe section shown below going from middle to left in the first photo, attaches inside the plane at the baggage floor ribs.

Typically, the flange is riveted to the skin, but I wanted to make my steps removable since they are prone to cracking.  To make them removable I need to drill the flanges for 8R8 screws.  I'm also counter sinking them to improve their appearance.

The 1/8 and 1/16 markings on the flange indicate the measured curvature required at that location.  More on that later.

A plastic block is drilled to receive the end of the pipe.  The block is bolted to a baggage floor rib.  A few additional holes are drilled in the plastic for rib attachment bolts and for a bolt that captures the end of the pipe.

The next step is to test fit, and it is noted that the flat flange does not follow the contour of the curved fuselage.

Both vertical edges and the lower edge require a beat down with a hammer to fit the fuselage.

Now that the flange fits fairly well it's time to match drill the flange to the skin.  Although the pictures show the flange already counter sunk, at this stage the flange was only drilled to #30 so that the match drilling would accurately locate the screw holes in the skin.

With the screw holes are drilled, the nutplate retaining rivet holes can be located and drilled with a nutplate jig.  Not all of the holes were drilled at the time of this photo.

After all of that the steps are temporarily clecoed on so I could admire the progress.  Upside down, they don't make much sense to Trina.  It's hard to impress a puppy.