Building, testing and operating an experimental aircraft

Showplanes Fastback: Canopy Layout

28 May 2014

Once the weather started to warm up in late May, and the temperatures in the gargage were favorable for composites layups, Dad and I began work on the Showplanes canopy and bubble.

Canopy Stiffener Bonding

Dad did the bulk of the tedious work early in the month, bonding the canopy frame stiffeners in their assigned positions, then filling and sanding the fillets.

Canopy Latch and Lock

Then Dad drilled the tricky holes for the canopy latch and lock, and built up around mechanisms with an epoxy/flox mixture.

Stiffeners Bonded

Once the stiffeners were bonded and the latch handle was in place, we were ready to fabricate the latch mechanism from the included steel tubing.

Latch Mechanism

Above you can see the rear latch mechanism under construction. The spring helps keep the canopy latch in the closed position.

Aft Closure

Here’s the completed aft closure, minus the taxi block and pin, which holds the canopy open about 4 inches while taxiing, to provide some airflow and passenger cooling.

Forward Lever

After we had latch mechanism installed and working smoothly, we moved on the the dreaded plexiglass bubble.

Trimming the Bubble

We started with some test trimming on the aft edges of the bubble (the throwaway areas), using an air-driven cut-off wheel. This worked passably well, but our 30-gallon compressor couldn’t keep up.

The Big Cut

So Dad opted to switch to the Dremel tool with a metal cut-off wheel, which held up well to the difficult plexiglass and compound curves.

Fit and Trim

After the Big Cut was done, we moved the plexi onto the fiberglass canopy frame for test fitting and trimming. This process took several hours of back-and-forth measuring, testing, and re-trimming.

Head Clearance Test

One important key to our success was a centerline mark that we had drawn on the plexi before making our first cut, which helped keep everything lined up and helped us avoid cutting too much of of one side or the other.

Drilling the Bubble

Lastly, we drilled the bubble to the canopy frame, using a plexiglass bit in the air drill. We worked from back to front, and alternated sides after every two holes to ensure we were getting everything even.

Damn Nice Profile

We ended up with a desireable profile, with the bubble being neither to high or too low. Hopefully the head clearance will still be there once we get the Oregon Aero seat cushions in there!

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