Getting baffle seal to behave

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The baffle seal between the upper cowl and duct that goes down to the intake manifold has a "hump" in it right in front of the intake. Anybody have any ideas on how to get it to lay flat and not interfere with air flow?

You might try heat forming it or cut a small pie wedge out. Punch a round hole at the point of the pie piece to prevent tearing, kinda like a drill stop hole.

Roberta

When you are flying it probably is laying flat.

Kent

A simple cut...

robertahegy said:

You might try heat forming it or cut a small pie wedge out. Punch a round hole at the point of the pie piece to prevent tearing, kinda like a drill stop hole.

Roberta

Click to expand...

Actually, just a slit and allow the two sides to overlap a bit would do it.

As long as the seal material you are using is reinforced, the cut won't propagate...

I presume it has some structure underneath it to lie down flat on in front of the duct...

gil A

my .02

kentb said:

When you are flying it probably is laying flat.

Kent

Click to expand...

this is what i think as well. however you could do all the other fixes which would most likely work.
hmm after looking at it again it may be that the scoop is/ has blown it to this shape, with the heat as well. could you shorten the seal ..trim it abaout 1/4- 1/2 an inch.

Bubblehead said:

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The baffle seal between the upper cowl and duct that goes down to the intake manifold has a "hump" in it right in front of the intake. Anybody have any ideas on how to get it to lay flat and not interfere with air flow?

Click to expand...

I had a few puckers at the rear corners of my baffle seals and like others have suggested I cut small "V" slots in the material, however I went one step farther and stitched the "V" slots closed with a heavy duty needle and waxed dental floss.

Those are all great ideas. I like the small cut out "V" which is then stitched together.

One other problem has presented itself. The builder (not me) used SCAT tubing to go from the air filter box to the induction box. Here's a picture. The picture shows the tubing loose from the air cleaner box. The correct part is shown in "27 Years of RVator" on page 250, originally published in the 1st 1998 issue.

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I talked to Vans today and there should be a fiberglass duct where the SCAT is. I have ordered the part but it would help me to see pictures of the correct installation. I'd appreciate it if someone could post a link to pictures of their installation.

Thanks,

Bubblehead

Bubblehead said:

I talked to Vans today and there should be a fiberglass duct where the SCAT is. I have ordered the part but it would help me to see pictures of the correct installation. I'd appreciate it if someone could post a link to pictures of their installation.

Click to expand...

You didn't say which model RV you are building - it looks like an RV-8, but it is hard to tell for sure.

You can see a few pictures of my induction air snorkel in the following links:

http://www.kilohotel.com/rv8/article.php?story=200210291612498
http://www.kilohotel.com/rv8/article.php?story=2002110914444814
http://www.kilohotel.com/rv8/article.php?story=20021111212801230

Just what I needed!

Kevin,

Sorry for not stating the model. It is a RV-8 with 180 hp IO-360. It's been flying for 6 years but I just bought it on September 1. I've started doing the condition inspection by taking all the cowls, access panels, etc. off, draining the oil, removing the oil filter and generally doing all the work I can before the A&P shows up Saturday afternoon. When I took the lower cowling off I was disturned to find the SCAT on the induction of the engine and figured something wasn't right.

The pages from your website were just what I needed! They show the fiberglass snorkle and your comments on installation will be very helpful. In talking with Vans I also found out the trap door is supposed to have a cable running from it to the cabin. Mine doesn't! If you have any pictures of that portion of the installation please post links.

So far the other squawks are an inop ELT, and the cabin heat muff was mounted too close to the other exhaust pipe (4 into 2 Vetterman) and melted! Pictures are on their way via email to Vetterman for guidance.

Thanks again for the very useful reply and the help.

John

Bubblehead said:

The pages from your website were just what I needed! They show the fiberglass snorkle and your comments on installation will be very helpful. In talking with Vans I also found out the trap door is supposed to have a cable running from it to the cabin. Mine doesn't! If you have any pictures of that portion of the installation please post links.

Click to expand...

Try these pages:

http://www.kilohotel.com/rv8/article.php?story=20040516192156719
http://www.kilohotel.com/rv8/article.php?story=20040613205257555

And, one more on the basic snorkel fit:
http://www.kilohotel.com/rv8/article.php?story=20030701211023375

Excellent pictures and explanation. They will help a lot. I will print out those pages and take them with me to the hanger to compare parts. It appears that the entire snorkle system on my plane is non-Vans! Does your system have the same tube in the left cowl inlet? that is shown in my first picture

Just for comparison, here are pictures of my air cleaner box, with the old air cleaner element and one with the element lifted up. In the second one, you can see the little spring loaded flapper door that I guess provides alternate air and opens if the pressure drop across the filter gets too large.

If anybody has seen this system before please point me to the developer.

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Bubblehead said:

In talking with Vans I also found out the trap door is supposed to have a cable running from it to the cabin. Mine doesn't! If you have any pictures of that portion of the installation please post links

Click to expand...

John,

This was a change Van's came out with later on. You only need alt air intake if you fly IFR, IMHO. I elected not to install the alternate air door in my VFR ship. However, should I ever upgrade to IFR, you can bet I will install the door.

The reason for the change was that the early design used a magnet to hold the door closed. On some installations, the engine ingested the hardware holding the magnets on. Not a good thing.

Bill - Thanks for the additional information.

Bubblehead said:

Excellent pictures and explanation. They will help a lot. I will print out those pages and take them with me to the hanger to compare parts. It appears that the entire snorkle system on my plane is non-Vans! Does your system have the same tube in the left cowl inlet? that is shown in my first picture.

Click to expand...

I've never seen a system like this before. It is possible that the original builder came up with it because he wanted an alternate air door, and Van's snorkle didn't have one of those at first. Van eventually added an alternate air door to his design. Look here:

http://www.kilohotel.com/rv8/article.php?story=20040516192156719
http://www.kilohotel.com/rv8/article.php?story=20040613205257555