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  #1  
Old 03-12-2016, 10:28 PM
Blain's Avatar
Blain Blain is offline
 
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Default Baffled by baffles

I'm convinced if Vans sent baffle kits first instead of empennage there would be very few RV's in the air....

Looking at the transition of seal material from the forward section behind spinner to the inlet ramps. It is an abrupt step the looks like it would leave a void for air to leak.

How have others handled this area?
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  #2  
Old 03-13-2016, 12:19 AM
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akarmy akarmy is offline
 
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I trimmed the inside of the ramps to clear that vertical baffle by a bit. Then filled in the ramp on the inboard side to keep air from spilling through the ramp area. Then leaving the baffle quite tall in that area I attached fabric about half way down, just a narrow wiper strip that pressed up against the solid surface I glassed in to the side of the ramp area. It took two separate parts attached together at the corner to wrap around that area.

Cooling ramp close out by Andy Karmy, on Flickr

Setting the baffle height with paperclips by Andy Karmy, on Flickr

RV-8 FWF by Andy Karmy, on Flickr
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  #3  
Old 03-13-2016, 07:17 AM
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Mark Dickens Mark Dickens is offline
 
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Default

No need to plug the ramps, if you do this right. The trick to the forward section of the baffles is to understand that the upper cowl ramps rest down on top of the baffle material to create the seal. Trim the ramps to where they are close to the baffles on both sides (~3/8" or so) and then form your baffle fabric curves to match the underside of the ramps. If you do this right, and in combination with the other pieces of baffle fabric involved (particularly on the lower cowl inlets), you will have it sealed pretty well.

There are a couple areas where Vans baffle instructions could be significantly improved, and this is one of them. It won't hurt to plug the ramps, but it's not needed.
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  #4  
Old 03-13-2016, 12:20 PM
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A post from a thread on the subject specific to the OPs question.

http://www.vansairforce.com/communit...4&postcount=18
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  #5  
Old 03-13-2016, 12:50 PM
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Thanks for the visual, Andy. Last pic tells the story. Didn't consider moving the fabric down lower on the baffle.
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  #6  
Old 03-14-2016, 08:45 PM
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[quote=Blain;1061833]I'm convinced if Vans sent baffle kits first instead of empennage there would be very few RV's in the air....
QUOTE]

My sentiments exactly! This is quickly becoming the least favorite part of my entire build.
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  #7  
Old 03-14-2016, 10:52 PM
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skylor skylor is offline
 
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Quote:
Originally Posted by Mark Dickens View Post
No need to plug the ramps, if you do this right. The trick to the forward section of the baffles is to understand that the upper cowl ramps rest down on top of the baffle material to create the seal. Trim the ramps to where they are close to the baffles on both sides (~3/8" or so) and then form your baffle fabric curves to match the underside of the ramps. If you do this right, and in combination with the other pieces of baffle fabric involved (particularly on the lower cowl inlets), you will have it sealed pretty well.

There are a couple areas where Vans baffle instructions could be significantly improved, and this is one of them. It won't hurt to plug the ramps, but it's not needed.
I've seen a lot of builders extend their inlet ramps out beyond the side baffles, but per my RV-8 FWF plans circa 2006, my interpretation was that the upper cowl ramps are inside of the baffles (for both the parallel valve and angle valve engines). I built mine with the fiberglass ramps completely inside of the baffles and the baffles seals lay against the cowl and not the ramps. My ramps are open on both ends. I have excellent engine cooling with this arrangement.





Skylor
RV-8

Last edited by skylor : 03-14-2016 at 11:47 PM.
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  #8  
Old 03-15-2016, 11:00 AM
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Blain Blain is offline
 
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Quote:
Originally Posted by skylor View Post
I've seen a lot of builders extend their inlet ramps out beyond the side baffles, but per my RV-8 FWF plans circa 2006, my interpretation was that the upper cowl ramps are inside of the baffles (for both the parallel valve and angle valve engines). I built mine with the fiberglass ramps completely inside of the baffles and the baffles seals lay against the cowl and not the ramps. My ramps are open on both ends. I have excellent engine cooling with this arrangement.





Skylor
RV-8
So the inlet ramp is narrower then the baffles, correct? And it looks like you used a reinforcement strip on the inside of the fabric. I considered that but wondered if it was overkill. Sure looks better.

Edit; OK, I re-read your post and I understand better now.
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Last edited by Blain : 03-15-2016 at 11:29 AM.
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  #9  
Old 03-15-2016, 01:20 PM
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Default Seal Reinforcement

Quote:
Originally Posted by Blain View Post
So the inlet ramp is narrower then the baffles, correct? And it looks like you used a reinforcement strip on the inside of the fabric. I considered that but wondered if it was overkill. Sure looks better.

Edit; OK, I re-read your post and I understand better now.
Yes, I fabricated the doublers to rivet over the seals primarily so the seal material would lift between the rivets and cause air leakage.

skylor
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  #10  
Old 03-15-2016, 09:36 PM
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Skylor, what did you use to stitch the sections together? Looks like staples.
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