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  #1  
Old 11-26-2013, 02:43 PM
Selmax Selmax is offline
 
Join Date: Aug 2012
Location: Berlin.Germany
Posts: 25
Default Baffle seals

I bought a flying RV9. From the first flight I knew the baffle seals need my attention. I would like to redo them, the old ones are no good example to follow. The difficult parts seem to me beeing around the airinlets and the center front section. Does anyone would like to help me with some photos showing how the baffle seals should look like?

Thanks for your help!

Pit

Last edited by Selmax : 11-26-2013 at 02:53 PM.
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  #2  
Old 11-26-2013, 02:48 PM
Sid Lambert Sid Lambert is offline
 
Join Date: Jul 2005
Location: North Atlanta
Posts: 1,120
Default

You can get a copy of the baffle plans from Van's for $10. They are on the web store.
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  #3  
Old 11-26-2013, 02:52 PM
Selmax Selmax is offline
 
Join Date: Aug 2012
Location: Berlin.Germany
Posts: 25
Default Vans

Sure, but they do not show the baffle seals, sorry!
Pit
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  #4  
Old 11-26-2013, 02:58 PM
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LifeofReiley LifeofReiley is offline
 
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Location: Round Rock, TX
Posts: 3,778
Default Look Here...

Down the page a bit...

http://www.vx-aviation.com/rv-9a/pho...wd_photos.html
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  #5  
Old 11-26-2013, 03:35 PM
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rzbill rzbill is offline
 
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Location: Asheville, NC
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Pit,
Look at the links in Reileys post above from Vern Little's blog. I imagine his work well because of the modification he did to the air inlet ramps on the top cowl. If your cowl does not have similar, it may be difficult to make the fabric fit to the top cowl on either side of the nose.

His picture is of the ramps before they are on the cowl so it may not be clear what is going on.
I did similar and the relevant cowl link is below.

Cowl Ramps

I don't have a pic of my baffle fabric but it is very close to Vern's.

EDIT ** Thanks for the correction Reiley

Good luck.
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Last edited by rzbill : 11-26-2013 at 06:04 PM.
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  #6  
Old 11-26-2013, 05:39 PM
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LifeofReiley LifeofReiley is offline
 
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That came from the Vern Little Blog... I used poured foam and carved then glassed the ramps in.
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  #7  
Old 11-26-2013, 08:06 PM
bruceg bruceg is offline
 
Join Date: Sep 2011
Location: AL
Posts: 69
Default Center Baffle to Cowl Seal

Quote:
Originally Posted by scsmith View Post
Most of the baffles I've seen leak in that area.

If you want the baffle to be cut to fit the inlet ramps in the top of the cowl, the issue is that the baffle turns 45 degrees and angles toward the center of the engine, then joins the part of the baffle that straddles the nose of engine behind the spinner.
At some point, that 45-degree portion steps off the side of the inlet ramp, and that is a problem area. After scratching my head for many hours, I built a fiberglass transition surface between the inboard edge of the inlet ramp and the top of the cowl. I made it out of flat segments of foam glued together, then glassed over. So my baffles are cut to mate to this transition surface. It is a bit of a complicated shape, but one that allows the rubber seal to conform to the shape and seal. With all other aspects of my cowl and baffles stock, my CHT's are 270--290F at 2400/24".

The other approach that can be made to work well, probably easier than what I did, is to trim the intake ramp so that the baffle never touches it - the forward baffle fits to the original cowl surface everywhere. Now, you must be sure that there is no flow path around the inboard edge of the inlet ramp, then outboard to the other edge of the inlet ramp, and then dump air into an area that is outside the outer side baffles. So what most people do is close off the end(s) of the inlet ramps.

Hope that helps.
After seeing Steve's post, I did something similar.

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  #8  
Old 11-27-2013, 09:52 AM
jimbo jimbo is offline
 
Join Date: Apr 2006
Location: Howell, MI
Posts: 304
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Pit,

Reily has done good work and his pictures are great. As you start to cut the first piece of rubber for a new baffle seal you will want to throw it out to tweak it. Start with making the pieces from a pattern. Use heavy fabric or best yet some rubber from an old inner tube. Tape the pieces in place with gorrila duck tape and check the fit. Re-cut the pieces to re-tweak as necessary for a good seal. Once satisfied trace off from the pattern to the final rubber. It takes time to get a good seal. One other thing. Don't be concerned about making the right side pieces the same shape as the left side. They won't be because the baffle ramps from one side to the other will not be exactly the same or in exactly the same place.

My 2 cents worth.

Jim
RV9A flying
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  #9  
Old 11-27-2013, 04:37 PM
whd721 whd721 is offline
 
Join Date: Oct 2007
Location: Beaverton, OR
Posts: 233
Default

Thanks for the discussions.

I am starting the baffle fabric this weekend.

One question; Is there a rule or guide for the location of the overlap joints. Specific locations? or convenient location?

Some items I intend to try;
1. ACS has sheet neoprene 1/8" x36" I intend to use as a pattern material.
2. McLane has Al baffle screws I intend to use for trial fit and removal tests with Al strips to sandwich the fabric.

Any experience with this stuff?
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  #10  
Old 11-27-2013, 05:18 PM
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Vlad Vlad is offline
 
Join Date: Oct 2008
Location: Utah
Posts: 8,311
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This is how baffles look on a Russian RV9A. AlexK of Moscow.


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Не имей сто рублей, а имей сто друзей.
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