Baffle Question - Shape of Front Baffles

JVolkober · #1 06-29-2010, 09:24 PM

Working on an RV-9A with an O-320 and Vans baffle kit. Not sure how to trim the baffle sections behind the prop/spinner, the sections that project forward to the cowl inlet. It appears that I should cut them down to conform to the shape of the inlet ducts. Can anyone provide me with a picture of what this looks like? Additional input would be appreciated before a break out the snips and start cutting.

Greg Arehart · #2 06-29-2010, 09:30 PM

John,

I don't have photos, but basically my baffles are cut slightly short of the cowl inlet, i.e., so that there is about a 1/4-inch gap. This ends up being sealed by the flexible baffle material. Smaller gap may make it more difficult to get the cowl in place and may rub when the engine shakes on startup; larger gap is easier to fit, but then the baffle material has to span a larger gap and may not seal quite as well. Expect to cut a fair bit of material off of the baffles to make them fit - they start out way oversized. Hope this helps.

greg

robertahegy · #3 06-30-2010, 05:13 AM

This is a pic of my 7A with 0-360. Your's should be shaped similarly. Hope this helps,

Roberta

Bob Axsom · #4 06-30-2010, 05:45 AM

This is a photo of mine taken during the build on 9-3-99. Notice that the rubber on the front of the baffle goes all the way to the front of the cowl, wraps under the outer edges of the inlet and is riveted to the baffle inlet ramp. The overlapping rubber seal strip attached to the bottom of the cooling air inlet of the lower cowl and extending over the baffle inlet ramp was not installed yet when the photo was taken. Six years of flying and no performance or service problems.

Bob Axsom

vlittle · #5 06-30-2010, 07:49 AM

I have several photos starting about half way into this site: http://www.vx-aviation.com/rv-9a/pho...wd_photos.html

Vern

JVolkober · #6 06-30-2010, 09:26 PM

Thank you for all the great information and pictures. This will be very useful.

John

rv9av8tr · #7 06-30-2010, 11:04 PM

And you can find all my baffling baffle pictures starting here:
http://picasaweb.google.com/mikerv9a...29728730728914

kentb · #8 07-01-2010, 10:06 AM

Quote:

Originally Posted by rv9av8tr

And you can find all my baffling baffle pictures starting here:
http://picasaweb.google.com/mikerv9a...29728730728914

A couple of observations on the pictures.

1. The air blocks in front of #1 and #2 will need to be modified after you start flying to balance them with #3 and #4. It looks like you riveted them in place which will make it hard to change them. If you had not already done this step I would have recommended using platenuts and screws to attach them, so they can easily be replace or removed.

2. The Alternator blast tube should be aimed at the back of the alt. From my understanding the side (where your are not pointing) is where the air exits the alt. The back is where the diodes are and that is what needs the most cooling.

3. A number of people have had problems with the oil cooler causing cracking of the back baffle. Because of that I added the a brace to the back baffle.

Kent