47 – Cowl Baffle Part 1

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After all the dusty composite work over the last few weeks, I almost enjoyed getting back to deburring : )

There are a lot of parts that make up the engine baffle, and I’m really grateful that Vans have done all the hard work in producing the intricate shapes which hug the engine.

I deburred all the parts first, and then dimpled/match drilled etc according to the manual.

After clecoing together the components, I test fitted them to the engine. Amazingly the only area which needed a trim to ensure a fit was the CB-00011 Left Fwd Baffle, where it mates to the engine behind the propeller governor.

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But there is a composite component to trim … the CB-00020 Air Filter Frame.

The Dremel cutting disk easily did the job, but the dust returned!

Actually, where possible I’ve been doing all the composite trimming/sanding in my spray booth enclosure. This keeps the dust away from the rest of the workshop.

Of course there is a vacuuming job to do before any spraying!

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Once trimmed and sanded to the scribe lines, the Air Filter Frame is match drilled with the CB-00009 Left Air Ramp.

As an aside, I’ve noticed this manual section is slightly harder to absorb. In the rest of the manual whenever a part is described it includes the part number. For some reason, in this section they mention the number once and then only the part description thereafter. It’s just needs a bit of back pedalling to remember which part is the “Left Air Ramp” or “Air Filter Frame” etc.

But overall the manual for this kit is fantastic.

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So how to finish the baffle?

Leave bare metal, spray with high temp paint?

We decided to get it powder coated since our chap had made such a good job of the instrument panel : )

Rather than deliver a box of small parts to the poor man, we riveted together the four main sections.

So I primed the areas which will be hidden by the various joints.

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The baffle assembly proved a good riveting workout, needing most of the techniques utilised over the build.

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The CB-00037 5″ Flanged Duct is attached with AN470AD4’s, and the C-Frame proved useful again during back riveting.

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Due to the duct’s angled tube, one of the rivets couldn’t be set with the C Frame … luckily the squeezer could reach that one …

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… and another one needed the angled face of a bucking bar.

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The CB-00033 Air Filter Frame Cover and the CB-00034 Right Air Ramp Cone have to have a cone formed, which mates with the vertical edges of the side baffles to form a streamlined outer edge.

This bit does come later on in the manual, after the baffle is finally attached to the engine. But since I wanted these items to be included in the powder coating, I leapt ahead and fabricated these.

There are templates in the manual which can be printed out at the correct size, and then temporarily attached to the workpieces to act as a bending guide.

Vans suggest a practice on a piece of similar thickness aluminium, which sounded like a top idea, so I did!

I placed some aluminium angle in the vice to provide a sharp, clean edge. Having carefully positioned the workpieces along the template bend lines, & then hitting with a hammer via the suggested plywood seemed to work well.

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After the clean bends have been accomplished, a bit of fine tuning by hand soon gets the correct profile.

As with many tasks in this build, it proved easier than expected.

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The CB-00033 Air Filter Frame Cover cone has a #19 hole which is match drilled into the CB-00001 Cylinder 2 Baffle.

Since I was doing this before the baffle was attached to the engine, I was careful to make sure the geometry was correct.

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Then a nutplate is located and its attachment holes match drilled.

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Similarly, the CB-00034 Right Air Ramp Cone is match drilled, and the holes dimpled.

Here are the collection of parts and assembled components ready for powder coating.

So I jumped in the car and delivered them … they’ll be back next week ready for final assembly.

See Part 2 …

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