Baffles #1

Time: 6 Hours

For Lycoming type engines cooling is paramount as they are air cooled. Just scooping air at the front of the engine cowl isn’t enough to keep the engine cooled properly. You need the cool air coming in the cowl to penetrate all the cooling fins of the cylinders. To do this you need to create a positive pressure and direct that pressure around the engines cylinders. To do this you use baffles which direct the air around the engine. The baffles are just a collection of parts that seal up the engine area as to direct the pressurized air. On the top of the baffles will be a rubber seal that will compress against inside of the upper cowl sealing that area. To start I have to separate several individual parts and remove some unwanted areas.

After those parts were all separated, edges cleaned up and deburred I started working on the individual sides of the baffles. The baffles are separated into several sections that all come together to form the entire baffle system. I follow the plans and started with the left after portion. This section is comprised of several parts.

Normally in this area Vans calls for the oil cooler to be mounted on theaft portion of this baffle. However I am using the remote oil cooler mount from so I’m not cutting the normal opening in this area but I’m still putting the bracing to add structure. The aft and side portion are riveted together along the corner but I’m going to wait to rivet them until final assembly when they’re all in place to make it easier to install. Moving forward I primed the surfaces of each piece that would touch each other for now, I will be priming and painting after all the fitting/cutting is done. The baffles get held into place with a series of screws that’s match holes in the engine case. The screws go through the baffles and that area needs to be strengthened so there are doublers in those areas. I riveted them first, then the angle bracing and then worked on the the rear bracing. I used my pneumatic squeezer for most of them but had to get creative on some. I reached into my drawer and grabbed the bucking bar that I had drilled a hole into for my dies. Using the die to cup the rivet head I used my back riveting set to rivet.

After they were riveted I put the left aft side portion in place to see how it fit. I needed to tweak the area around the valve cover to get it to fit as the shape is off just a little. It still needs work but it’s in place for the initial mock-up.

I then worked the left aft section in place. This is a little difficult to say the least as there are a lot of folds, bends and corners to deal with in a tight space. Once in I cleckoed the corners together combining the aft and side parts together.

I repeated the process for the right side aft section which goes in a lot easier.

The forward sides have the same doublers for the screws as the aft sides.

That’s where I quit for the day, progress is the key. Next I will work all four valve cover areas so they fit nice before moving forward.

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