Step Indentation

In today’s post, I’ll cover the trials and tribulations of preparing the fuselage to accept the metal step that is called for in the plans.  A lot of people are moving away from the original step design and putting in retractable steps, but I’m not willing to go through the trouble for something that is aerodynamically insignificant, with the replacement potentially adding weight.  It’s mainly a cosmetic decision.

There are a couple of important things that you have to do to mount the step, and there are a couple points that the plans do not really make clear. The first issue is that the drawing for the wooden reinforcement comes directly from the long ez plans… or was it the cozy 3 plans? At any rate, the shape of the wooden insert is significantly different than shown.  The second issue is where the step actually fits.  You need to look ahead to chapter 8 to see where to mark the bolt line on the step that should be coincident with the longeron. Third, the plans do not mention the difference in curvature between the pre-manufactured step and the curvature of your fuselage.

First off, here’s what my cutout into the foam looked like.  A scary thing to go cutting into your recently shaped fuselage, for sure.

The cutout

As you can see, I simply scraped the foam away with a chisel.

At this point, I think I had been assuming that the step surface was flush with the longeron.  This is incorrect. The correct placement of the step and the issue with the step curvature I tackled at the same time. The first job was to make a wooden block to fit in the foam recess.  The foam is much shallower here than in the drawing, so even though I started with a 1/4″ piece of birch plywood, It got shaved pretty thin.  At the same time, I carved an indentation into it, so that I could have the curved section of the step recessed into the fuselage, so the upper surface would sit more or less flush.

Wooden insert

Insert in place

So at this point, having drawn the correct bolting line on the step, I gave it a little test fit:

Test fit

As you can see, I had carved away a bit much of the wood, based on my initial thoughts on where the step mounted. At this point, I carved away a bit of the longeron and the foam above the longeron so that the step would recess a bit:

recessed

At this point, I decided that I was going to simply fill in the gaps around the step with flox.  I wrapped the curved part of the step in packing tape, to act as a mold release, and put tape all around the perimeter to protect the surrounding foam.

Ready for Flox

I then floxed in the wooden block, filled the recess part was with flox, and smooshed the step down into it.  I wish I had taken a picture of this, but I clamped together a structure with a square up against the fuselage and the surface of the step, to ensure that it would be perpendicular to the sides. The following day I had no problems pulling the step right off.  More on the step to come when the blog catches up into chapter 8!

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