Ch. 4 - Instrument panel - Part 5

Sharp edge removal (12.5 hrs)  

I thought I was done with chapter 4, but there was still one last issue I had identified early on, that I wanted to take care of before permanently installing the instrument panel.

I debated over the necessity of the modification, but in the end I decided that postponing it would have just complicated the procedure, or might have never gotten done at all.

I first noticed the problem when trying to get in and out of the wooden mock-up I had previously built. I found it difficult getting my legs past the instrument panel without leaving some skin on it, particularly since moving the seat forward by 2” further reduced the space available to maneuver about. 

While that might be a slight over-dramatization, I was concerned about banging my flash on such a thin bulkhead in case of strong turbulence or, God forbid, a forced landing. 

In the motorcycle design industry, this area of interest is known as “passive safety”, or a design feature intended to reduce the risk of injury, as opposed to “active safety”, such as an ABS breaking system, for example.

Not convinced? Need more examples of passive safety? Ok, how about the round metal balls at the end of motorcycles' brake and clutch levers? Those are designed to not penetrate a thigh during a crash. How about the smooth transition from the motorcycle seat to the fuel tank, or the below-surface fuel tank cap? Those designs are intended to prevent you from leaving your “family jewels” behind, as the force of the accident propels you sliding forward over the gas tank.

Yeah, I thought that would strike a nerve!

So... back to my concern. 

As you can tell from the next photo, my friend Steve has given some thought to the issue, no doubt as a result of some scraping incident. His idea was to cover the sharp edge with some fuel line slit down the middle. Effective perhaps, and easier to do after the plane was built.

Since I am far from completion, I decided to go the more difficult, and permanent route, and modify the instrument panel now, while I could still flip it whichever way I needed. 

Below you will find pictures showing the complete sequence of how I accomplished that, keeping in mind that a little more integration with the nose structure components will have to be accomplished in a later chapter.

"Necessary roughness"

Removing foam

Foam and dried micro removed from fiberglass

Flox in place of foam (I used West epoxy since this is not a structural feature)

Glueing leftover foam to the front side of the instrument panel

Excess foam was later removed with a hot-wire cutter

Foam leveled with the hot-wire cutter, and sanded to the desired shape

Scraps of BID at 45˚ reused here

Dried glass protruding into the cockpit (back) side

Glass trimmed on the back side. You can start to see the much thicker profile.

Removing all the foam from the instrument panel 

Foam removed and fiberglass trimmed

Glue removed and fiberglass sanded

Applying flox

Smoothing the transition

New fiberglass tying the front of the instrument panel to the new structure

Right side (as seen by the pilot) done

Side view of the "channel"

Both sides done and peel-plied

Opposite view

Curing overnight

Finished product after some sanding

Instrument panel forward face

Leg cutout details, as seen by the pilot.

Instrument panel walk-around

One added benefit is that, should a wire ever come loose and dangle, it might get cradled by the structure, thus avoiding being ripped by one of my boots while getting in or out of the cockpit.