Baffle Clamp Strips & Exhaust

Posted on 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.

One of the two heat muffs, with the other one in the background. This is showing the end caps and mounting rods, safety wired to the exhaust pipe.
Air ramps clecoed into position

Baffle Clamps, air ramps, & JDAir Latch

Posted on by Neal

Today I worked on fitting the JDAir latch mechanism into the slot, including installing the “dummy” rivets which only fill the existing holes and don’t clamp anything together. One of these rivets interferes with the latch, so a countersink is needed on the latch mechanism to work around it. With the countersinking done, I was able to fit the bottom bracket, and match drill the new rivet holes into the fuselage. Once I cleaned up the holes, I dimpled using a pop rivet dimple die. They never dimple very well, but there’s not much I can do.

Meanwhile, Dad worked on sanding and fitting the air ramps to the top cowl. These are basically ready to be epoxied into position now.

We also shaped the air inlet baffle seal clamps. Once these are bent to shape, they are wrapped in packing tape, and filler is applied to the inside edge of the cowling air inlet. The clamps are then used to form the correct shape. We did that, and will let it set overnight.

JDAir Latch

Posted on by Neal

Tonight I started working on replacing the Vans canopy latch with the JDAir latch. Originally I wasn’t going to do this, because it requires cutting a larger slot in the side of the fuselage, and I didn’t want to risk it. Additionally, a lot of the 3rd party side panels are only designed for the standard latch.

At some point over the last year or two, Classic Aero started selling side panels that fit the JDAir latch. Looking at the actual modifications needed, and how much more solid of a latch it is, I decided to go ahead and change it out.

I downloaded and printed the instructions, checked the dimensions, then taped the template to the fuselage. Step 1 is to drill out the rivets holding the bottom bracket in place. This was easy enough. Then I drilled holes in the corners of each area which needs to be enlarged, and then used a small Dremel tool with a cutting wheel to complete the cut.

Next I’ll need to file the edges to a nice, flat, smooth surface, but I’m relieved to have gotten the scary step done without any collateral damage.

Before, with the latch mechanism removed.
After making the cuts

Cowling and Exhaust

Posted on by Neal

Today we continued working on the cowling and the exhaust system.

While Dad handled the sanding and fitting of the cowling, I worked on setting up the exhaust system. First I assembled the support clamps, then applied anti-seize lubricant to the sleeve and ball fittings, then set it up underneath the engine.

With dad’s help we were able to mount the pipes onto the cylinders, doing up the hardware finger tight.

Using a roll of 3/4 inch electrical tape, I set the spacing correctly and installed the support clamps on the aft edge.

Dad did another round of filling today, as there is still a ways to go to achieve the alignment we need on the cowling air inlets. It’s amazing to watch him work, knowing just what’s needed to get the perfect fit and finish. At 79 years old he’s still putting in very long days, with no complaints.

Cowling Air Ramps, Exhaust, and Oil Door

Posted on by Neal

With my dad back in town and helping with the cowling again, we made progress today on a few fronts. Dad worked on installing the top cowl air ramps, and started on the oil door, while I focused on the exhaust system.

Before the air ramps could be installed, we needed to address the alignment issues with the front of the cowling. In a couple of sessions, Dad applied filler to the edges of the air inlets, and trimmed the air ramps to fit.

Meanwhile, I installed the first section of the heating system, the heat t-fitting. I left the clamps loose for now, as it’s hard to tell if this will need to be finessed into position later. I then drilled out a couple of rivets, and installed the FF-00084 cover. After some puzzling, I realized that this stops the hot air from escaping the system when the passenger vent is closed, and the pilot vent is open.

We then found and trimmed parts for the oil door.

Exhaust system

Posted on by Neal

Today I started on the exhaust system by cutting the scat tubing to length, and making up the flared-tube exhaust support fittings. No issues or challenges with this step, although I wonder how well these fittings will work. Hopefully they will grip the inside of the hose enough to hold on, I have read a few stories on vansairforce.net where these have let go. We’ll find out I guess.