The Showplanes Fastback modification is the best thing I did to this airplane, and the longest single task of the build. Across more than 60 build sessions spanning 2015 to 2017, I worked through structural modifications, composite work, and canopy fitting. Here is what I’d want to know at the start.
The kit and instructions
The Show Planes kit is excellent. It arrived complete, well-packaged, and inventoried in under 30 minutes. The instructions are thorough — step-by-step with photographs and diagrams. Van’s, take note.
That said, the instructions have not always kept pace with the kit. When I ordered, the manual described pre-drilling tasks that had already been completed on the current -1 fuselage. A few photos and measurements reference older parts that no longer match. When something doesn’t line up with the manual, call Bryan at Show Planes before improvising. He’s responsive, generous with his time, and has almost certainly answered your question before.
Cockpit rails
The new rails run flat and level — not sloped forward and down the way the stock Van’s rails do. I installed mine wrong the first time. The correction wasn’t difficult, but it cost hours and left a row of extra holes. Find the photo in the instructions that shows the final rail position and study it before you cleco anything.
Instrument panel — bend before you cut
If there is one thing to take from this entire summary, it’s this: bend the bottom of the instrument panel in a brake before making any cuts. I did it in the wrong order. The panel was already fitted, which made the required bottom bend considerably more stressful than it needed to be. It worked out, but it was completely avoidable. The instructions do not emphasize this clearly. Consider this me emphasizing it on their behalf.
A related mistake: I initially planned to taper the forward instrument panel cover, thinking it would improve access to the cockpit. The canopy skirt handles that entirely, and the bulkhead directly aft of the panel makes a taper structurally unnecessary. I caught this before it became permanent, but only just.
Fiberglass — what changed my results
The fastback involves a substantial amount of composite work. Several things improved my results significantly:
Hardener selection. My hangar runs well over 100°F in summer. The fast hardener gave me approximately 15 seconds of working time in those conditions, which is not working time in any useful sense of the phrase. Switching to slow hardener was an immediate improvement.
Skip the peel ply. I tried it. It was more effort than the result justified.
Use body filler sparingly. Rage Gold dries fast and sands fast. That’s genuinely useful if you enjoy sanding. In every other respect — strength, application, and end result — flox and micro balloons are better. Use body filler as a last resort for small surface discrepancies after micro work, not as a first pass.
Brush on your micro. I discovered this late. Mixing micro to a slightly thinner consistency and brushing it on rather than applying it with a spatula gives better coverage and easier sanding, because the surface density is uniform. Sanding across adjacent areas of hard flox and soft micro is unpleasant. Brush-on micro was the single biggest technique improvement I made on this build.
Cutting the canopy
This is the irreversible part. The canopy is plexiglass, and every cut is final.
The critical point: as you trim the sides, the curve radius decreases, and the trim line on the untouched side shifts inward. Trim one side, put the canopy back on the skirt, re-measure the other side, then trim. If you trim both sides together from your initial measurements, you will cut too much on the second pass.
Use a cutting disc without teeth. A Dremel with the right wheel gives good control. Warm the canopy if your hangar is cold. Measure at least four times.
Canopy skirt — don’t trim too much
I over-trimmed the skirt in one session and had to repair it with flox. This is fixable but slow. Err toward leaving material. It takes minutes to remove a little more; repairing an over-trim takes considerably longer.
Bonding the canopy
Hysol 9430 is the right adhesive for this joint. Flox or epoxy are wrong choices here — the thermal expansion difference between plexiglass and aluminum requires an adhesive with some flexibility.
Have syringes ready. During bonding, some areas will have air pockets or insufficient coverage despite careful preparation. A syringe lets you push adhesive into gaps after the fact — through the cleco holes, through the adhesive rivet holes, and along the interior seam. This is expected, not a sign of failure.
Tape placement for the interior work: leave a small gap between the tape edge and the skirt — roughly an eighth of an inch. I placed mine flush and spent hours removing it afterward. Use three layers: two of electrical tape for sanding protection, one of painter’s tape for a clean line. Remove the painter’s tape immediately after applying adhesive.
On timeline
The fastback took longer than I expected. That sentence has been written by every builder who has attempted it. The composite work is stop-and-start by nature — you apply, you wait, you sand, you prime, and you find something that needs attention. Budget more time than you think you need and resist the urge to rush the fiberglass stages.
Summary
The modification is worth it. The kit is well-made, the support from Show Planes is excellent, and the result is distinctive. The things I’d change: the instrument panel bend order, the approach to micro application, and my patience with the canopy skirt trimming. Everything else was learnable in the doing.