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Baffle material?

bnovak1220

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Patron
Hello all,
So I am working on the baffles and noticed others appear to have used material other than what Vans supplies in the kit. I have two links below to other products I have seen. I was wondering if any of you have input on whether it is better to look for a better material than what Vans supplies. I notice that Mcfarlane has a nice sales pitch for their cowl saver material but a little pricey - anyone used this product before ....after using something else and notice a big difference?


https://www.mcfarlaneaviation.com/products/category/baffle-seal-material/

https://www.aircraftspruce.com/catalog/appages/siliconecowlseals4.php?clickkey=4767

Thanks !
 
I have the 1/8" red version of the one Aircraft Spruce sells on my Cessna. In a couple places, it's tearing - not much, but it is. And where it rubs the aluminum cowl, it's wearing into the cowl.

I don't plan to use that material on my RV-3B.

Dave
 
Hello all,
So I am working on the baffles and noticed others appear to have used material other than what Vans supplies in the kit. I have two links below to other products I have seen. I was wondering if any of you have input on whether it is better to look for a better material than what Vans supplies. I notice that Mcfarlane has a nice sales pitch for their cowl saver material but a little pricey - anyone used this product before ....after using something else and notice a big difference?


https://www.mcfarlaneaviation.com/products/category/baffle-seal-material/

https://www.aircraftspruce.com/catalog/appages/siliconecowlseals4.php?clickkey=4767

Thanks !
I used the McFarlane Cowl Saver baffle material when I built my RV-10. Their demo at airventure made me a believer. I would use it again on my RV-9A, but am going to use a plenum on this one. The Cowl Saver material is not as flexible as the stuff Vans supplies so at the front of the engine, I used the Vans material and using pro seal as the adhesive and glued a strip of the cowl saver on the cowling itself where the material meets.
 
I was sent some samples of the McFarlane Cowl-Saver material, and it is nice - but I didn’t feel it was going to do anything that the Van’s material wouldn’t - I’ve used the Van’s stuff on all our airplanes, and haven’t had any issues. Fit it properly so you don’t have any folds or creases to let air through.
 
For those of you who have used the McFarlane product, what is your take on their claim of reduced vibrations, and of reduced wear on the cowl and associated fasteners?
 
I used the cowl savers material and liked it. The idea around it is that their material is very slippery on the top side that meets up with the cowl thus not transferring the vibration from the engine to the cowl. I put it on our -10 which had a 3 blade prop and was already smooth so I can't swear it did anything better but I will say it was very slippery material and their claim makes sense. they have a video online somewhere where it shows less vibration on the cowl with it on.
 
I originally had the Vans supplied material. I noticed that material started to get wavy and it was showing areas where air was getting through. I wanted a better sealed cowling and lower CHTs so I replaced it with the aircraft spruce silicone stuff. It seals much better on mine. CHTs were noticeable cooler and I could visually see air was not getting through. It stays more pliable over time.
 
Thanks so much everyone for the input. Really helps to understand these things when you hear peoples experiences in their builds. What Great Forum!
 
I used vans stuff on the 6A and it works well. On the 10, I used the ACS silicone stuff for the aft and sides of the baffles. I used full length strips and also mounted it with screws and and angle backing plate. This worked REALLY well. It made a perfect contour and I get great sealing from it.

I think I stole the idea from toobuilder and paddy.

Larry
 
I used vans stuff on the 6A and it works well. On the 10, I used the ACS silicone stuff for the aft and sides of the baffles. I used full length strips and also mounted it with screws and and angle backing plate. This worked REALLY well. It made a perfect contour and I get great sealing from it.

I think I stole the idea from toobuilder and paddy.

Larry

Pics? I’m thinking about replacing mine and your solution sounds interesting.
 
+1 McFarland

I used nutplates on a 1/2” wide backing with #8 screws for EZ removal & replacement. No leaks, stays cool & lo vibe.
 
Pics? I’m thinking about replacing mine and your solution sounds interesting.

Don't have one and it could be a bit before the cowl is off again (winter time :mad:). Mine looks very similar to the pic above. However, I used a single piece silicone strip. This approach allows a very nice curvature that conforms to the cowl top very nicely, if you take the time to lay it out correctly. The built in bend of the strip, due to the curvature, creates about 1/2 of the bend in the silicone, with the cowl forcing the other 1/2. I have a 100% wear pattern showing very good sealing. The silicone resists taking a set, like the rubber does, so there is good long-term tension available for sealing.

The single piece allows you to have a compound curve with NO waves. I will snap a pic the next time the cowl is off.

Larry
 
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Those of you who faired the sides of the nose gear slot in the lower cowl - what material and thickness did you go with, and did you butt the seal in the middle or leave a gap for the gear leg to move in?

If you didn't seal this gap, was it for extra cooling airflow because of issues?

I'm experiencing no CHT issues in climb or cruise and that's during break-in with no pants or leg fairings, no gills in bottom cowl. I have an AntiSplat cowl flap in the side but it makes only a 3-4 degree difference in CHT's that I can tell. An small air dam in the front will probably help a bit as 5 and 6 are typically 15 degrees hotter than 1-4. Looking to seal things up a bit more for drag reduction if the cooling air exit area isn't needed in the end...
 
Those of you who faired the sides of the nose gear slot in the lower cowl - what material and thickness did you go with, and did you butt the seal in the middle or leave a gap for the gear leg to move in?

If you didn't seal this gap, was it for extra cooling airflow because of issues?

I'm experiencing no CHT issues in climb or cruise and that's during break-in with no pants or leg fairings, no gills in bottom cowl. I have an AntiSplat cowl flap in the side but it makes only a 3-4 degree difference in CHT's that I can tell. An small air dam in the front will probably help a bit as 5 and 6 are typically 15 degrees hotter than 1-4. Looking to seal things up a bit more for drag reduction if the cooling air exit area isn't needed in the end...

I extended the slot enough for clearance. I then made an AL plate (063 with a backing plate to span the gap) to take up the excess space, leaving maybe a 1" relief for the leg to move. I never did testing to determine the performance improvemnt in either speed or CHTs. I just assumed the large gap would add an undesired increase in lower cowl pressure. I used four screws and nutplates to hold in the plate. Unfortunately I need a couple clecos to hold the plate in place to start the first screw. Not a lot of room for fingers to hold in place.

I am able to climb to 14000 in the hot summer with CHTs maxing at 400 - ROP.
 
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I suspect the wear people see in their cowl is due to an accumulation of oil and dirt at the interface creating an abrasive. The slickest stuff in the world will not help if you don't keep it clean.

I have had no issue with the Vans material.
 
I used vans stuff on the 6A and it works well. On the 10, I used the ACS silicone stuff for the aft and sides of the baffles. I used full length strips and also mounted it with screws and and angle backing plate. This worked REALLY well. It made a perfect contour and I get great sealing from it.

I think I stole the idea from toobuilder and paddy.

Larry

I tried some 1/8" thick silicone from ACS like the OP mentioned and it was really stiff compared to the Vans material and it didn't seal as well so I took it out. Which silicone material did you use from ACS?
 
I tried some 1/8" thick silicone from ACS like the OP mentioned and it was really stiff compared to the Vans material and it didn't seal as well so I took it out. Which silicone material did you use from ACS?

Just their house brand, low cost, 1/8" stuff. However, in my case the material was forced to follow a longitudinal curve which pre-bent the silicone about half way across its width. Therefore, much less tension against the cowl. Possibly this is why it worked well for me, but not others.

Larry
 
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