Cowling – RV-14 Build

Cowling Paint

Posted on June 15, 2025June 26, 2025 by Neal

Tonight I painted the bottom cowling white. This required carefully masking the edges of the heat shield, and the exterior, and then a few seconds of actual paint application.

The paint was fine. I used a high temp enamel spray paint, and it went on nicely. The paint really showed up all the areas where I had some stray fiberglass strands. If I did it again, I would have taken more time to sand the inside before painting. Still, I don’t plan to be showing off the inside of the bottom cowl to anyone.

The resin I used to seal the heat shield ran in a couple of places, and made an annoying couple of puddles. I could have used a lot less resin, and I should have realized that with no cloth to absorb the resin, it was going to run. No big deal.

Cowling Heat Shield

Posted on June 13, 2025October 13, 2025 by Neal

Tonight I finished applying the heat shield, and then brushed some epoxy resin around the edges of each piece, included all the places where edges overlapped.

Cowling Heat Shield

Posted on June 5, 2025June 26, 2025 by Neal

Tonight I started on the lower cowling heat shield. My plan is to get this applied, then paint the rest of the inside of the lower cowl white to make it easier to detect oil etc.

It took a while to work out the best way to work with the foil. Initially my plastic squeegee wasn’t stiff enough, and it wasn’t getting the air bubbles and wrinkles out. It was also a bit of a weird shape, and I had a couple of false starts getting the right size sections of foil cut and sized.

I ended up finding it easier to work with 18-inch sections at a time, which led to multiple overlapping pieces, but fewer problems with wrinkles and air bubbles.

I got about half way done applying the foil before calling it a night.

Getting started on the right side. Note the multiple bubbles and wrinkles.

Switching to a harder plastic squeegee made a big difference. Wish I had started that way.

Cooling Flap

Posted on January 20, 2025 by Neal

With the oil cooler in place, and the cowling holes drilled, I was able to final install the cooling flap, and hook up the control cable.

I found the screws and mounted the cooling flap assembly to the bottom of the fuselage. In the process I noticed a series of 4 pre-drilled holes in the bottom of the fuselage that I’ll need to investigate and probably fill. Two of them look like a spare antenna mount, and the other two could be drain holes.

Once the flap was in position I hooked up the control. It was a little fiddly to get it just right, but in the end it worked out ok. The flap closes and leaves a small cushion gap per the plans, and it operates very smoothly.

After I finished I noticed that the plans call for washes under the screws that hold the cooling flap in position. They aren’t mentioned earlier in the plans when initially test fitting the cooling flap assembly, so I hadn’t noticed them at first. I’ll have to find the washes and install them later.

Cooling flap assembly installed and taped down at the back end

Threading the control cable through the drilled bolt that acts as the pivot point for the flap door control

End of the cable after setting the length and bending and trimming the control cable

Bottom Cowl Screws

Posted on January 16, 2025 by Neal

Tonight I finished a job on the cowling, locating and drilling the screw attach points on the trailing edge. There are a total of 8 holes, 4 in the middle section, and two more on each side. There’s a template supplied for the outboard holes, so I made the template and drilled those outboard holes, then attached the heat flap to locate the 4 center holes.

I was careful to not drill into the nut plates, which would cause them to lose their ability to hold the screws.

Making the template. Simple cutting a part into two and using one half

Heat flap temporarily installed overlapping the cowling. This gave me the locations for the 4 holes in the cowling. When finally installed, the heat flap goes under the cowling.

Test fitting cowling

Posted on September 28, 2024 by Neal

Today we test fit the cowling, just a couple of hours before my parents headed off. The fit was much better and easier than I anticipated, but there was still something not quite sitting right. Later in the day I came back to troubleshoot and found one baffle seal that had flipped and was holding the two halves of the cowling apart. With that fixed, I was able to safely install all 4 of the screws around the air inlets.

Final test fit of the cowling, with everything sitting nicely in place

Baffle seals are looking good. The engine will sag as it’s broken in, which will change the geometry of these forward baffle seals. This is about where the plans say they should be. The seal circled in red was flipped and had been interfering during the initial test fit.

Oil Door, Gear Leg Fairing, JDAir Latch

Posted on September 27, 2024October 26, 2024 by Neal

Today we installed the oil door, and I riveted on the canopy latch bottom bracket. We also started on the gear leg fairing.

Gear leg fairings are held together with piano hinges on the trailing edge

Bottom bracket riveted into position. All in all, this was an easy modification and I think it was worthwhile

Oil door in position. This picture was taken a few days later, as I forgot to get a picture when it was originally installed

Oil Door, Cowling, Exhaust

Posted on September 26, 2024October 26, 2024 by Neal

Today we worked on the oil door, more sanding on the cowling, and the exhaust system.

After a lot of sanding and filling and sanding and filling, the cowling is basically done. In addition to all the sanding, Dad drilled holes, countersunk them, and installed nut plates while I supervised and learned. The inlets are nicely aligned now, and the baffle seals around the inlets are installed and ready to be test-fit. I’m curious to see how the bottom cowl will fit, as there is almost no room to maneuver behind the spinner plate. Hopefully we’ll get a chance to try to fit the whole thing together before mum and dad leave town.

We have also been working on the oil door, and have the nut plates installed on the top cowling. I primed the aluminum parts before wrapping it up for the day.

Oil door assembly before taking it apart to prime

Baffling & Exhaust

Posted on September 25, 2024October 26, 2024 by Neal

The air ramps looked good this morning, and Dad got busy sanding them flush. Once the sanding was completed, he added a few strips of glass to strengthen the air inlets, particularly on the inside edge of the outboard sides of the air inlets. A lot of the glass layers in this area have been sanded away in the process of fairing the inlet opening.

In parallel, I continued working on the exhaust system, finishing the heat muffs and connecting the various cabin heat components with scat tubing. I trimmed a little bit off one end of one section of hose, but everything else fit perfectly.

Laying up some extra glass in the corner for a little more strength.

Air ramps sanded and some extra glass and filler applied

Connecting the cabin heat system components. The scat tubing is secured using hose clamps

Support clamp for the long section of scat hose. Note the bead of RTV down the length of the hose. This prevents the exterior string from unraveling over time

Scat hose connecting to the pilot side hot air vent

Baffle Clamp Strips & Exhaust

Posted on September 24, 2024October 26, 2024 by Neal

Tonight I worked on installing the heat muffs. There are two of these muffs, arranged in series, that use exhaust heat to warm air which is then directed to the cabin warm are vents. The muffs are made up of sleeves that slip over the exhaust pipes, with end caps on each end. The end caps are held in place by two rods, which are safety-wired onto the exhaust pipe. The sleeves are held onto the end caps by hose clamps.

My first problem was that I had tried to outsmart the plans by putting the sleeves onto the pipes before they were mounted to the engine. Unfortunately one of the sleeves had flipped around, and I couldn’t reposition it without taking off the exhaust pipes. This was annoying, but not too much trouble. Going back to the step-by-step instructions, I installed the end caps and then called it a night.

Meanwhile dad was busy with more sanding and filling around the top cowl air inlets, and getting the air ramps to fit just right. Once the air ramps were close enough we glassed them into position. Because the engine baffle seals are already installed, we had to carefully position the clecos holding the air ramps into position so they wouldn’t interfere with the baffle seals when we installed the top cowling. Having the top cowl in position while the glue sets around these air ramps is important to ensure nothing is pushed out of alignment. We also draped a plastic sheet over the whole engine to catch any resin drips.