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-   -   Photos: Really good baffle seals (https://vansairforce.net/community/showthread.php?t=141528)

DanH 09-04-2016 09:17 AM

Photos: Really good baffle seals
 
Considering all RV fabrication tasks, the thing I most often see done badly is baffle sealing rubber. Flap seals arranged so they blow open, seals that seal against nothing, puckers, gaps, overlaps, you name it...the list of sins appears to be endless.

However, I have seen some installations that were beautiful. Believe me, I look; I'm the nut case who walks around fly-ins while peering into cowl openings like some kind of airplane up-skirt pervert ;)

Builders need to see some really good seals. Who has pictures? Who can show us how it's done? Post those photos please. You'll help a whole generation of RV builders enjoy lower CHT and oil temperature, while going faster due to reduced cooling drag.

az_gila 09-04-2016 09:31 AM

Great idea! I really had to do a lot of head scratching to even guess where the rubber parts go around the flywheel area and around the outer parts of the cowl air cooling inlets.

Not putting this out as "good" but this is Vans RV-7 picture for the O-360 baffle kit instructions.


DanH 09-05-2016 07:20 AM

What, no photos?

It's a sorry situation if nobody is proud of their baffle seals.

ERushing 09-05-2016 08:02 AM

Maybe we're a humble lot :) How about pics of some pretty darn good baffles??

az_gila 09-05-2016 09:05 AM

Quote:

Originally Posted by ERushing (Post 1109072)
Maybe we're a humble lot :) How about pics of some pretty darn good baffles??

Or even some marked up "I wish I had done this " pictures?

airguy 09-05-2016 10:37 AM

I went with a plenum mostly so I wouldn't have to mess with baffle seals!

rzbill 09-05-2016 04:04 PM

Place holder
 
Hi Folks,
I finally got a chance to take some better pictures to post here.

IMHO, good baffle sealing starts with the inlet ramp fabrication and planning how to do the interface between the ramps and the seal fabric.

Fabrication of the inlet ramps with modification

Here are overview pictures. The rear and side seals are easy and probably similar to every one else. The tricky bits are up front around the inlets.




Note the shape of the nose seals. With the ramp modifications in the link above, the seals have a place to sit. Ignore the gap at the top. Even though there is a pucker, it is sealed with adhesive.





The below pics were taken with a crappy borescope, sorry.
This one is the outer seal at #1 cylinder.




Outer seal at #2 Cylinder



Inner nose seal at #1 cylinder, close to cowl inlet



Inner nose seal at #1 cylinder, further into the cowl looking across towards the engine case.



Inner nose seal at #2 cylinder



Inner nose seal at #2 cylinder further into the cowl looking towards the engine case




Lastly, the wear pattern on the top cowl. I think it is pretty good. There are two places that still have slight puckers and the wear pattern is not as robust as I would like it. Its kind of a perfectionist project now since the cooling works great .


vic syracuse 09-05-2016 04:16 PM

Great thread, Dan. I will post some pictures when I get home. I will add that besides having the rubbe/silicone seals done well, it also helps greatly to use the high temp RTV around the areas where the baffles meet the crankcase, especially in the front of the engine. There is usually a lot of room for air to leak to the bottom of the cowl in these spots, thereby pressurizing the lower cowling and stopping the air flow from the top.
And don't forget to clean the sand casting between the fins around the spark plugs. Makes a big difference in cooling.

Vic

rightrudder 09-05-2016 07:00 PM

Here's mine. Seems to be sealing well so far, based on temps and wear marks on cowling & seal material.


bruceh 09-05-2016 09:41 PM

Here is mine at 300 hours.



More photos of them in my web site.


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