[David_Nelson]

Hi All,

I'm fitting/trimming the baffle material so that I can get the baffles squared away..mostly. Anyways, I can't figure out how to trim and place the baffle material on an outside corner so that it seals against the cowling. This is the outside corner that I'm talking about:

I know there's supposed to some sheet-metal here that would make this easy but I'm going a different route by adding a support strut and mounting the oil cooler as high as reasonably possible.

Thanks!

 

[L.Adamson]

This is how I did it. The rivited pieces can also be sewn together. Some builders attach a straight piece across the top to attach the baffles to. You should be able to find some websites that show this.




L.Adamson --- RV6A (flying)

 

[49clipper]

49clipper

Be aware of those exposed rivets in the baffling. I have seen way too many times when those rubbed a hole in aluminum cowlings.

 

[David_Nelson]

Thanks

Aha! Isn't that clever. I'll be sure to sew mine.

Thanks Guys!

/\/elson

 

[N130WN]

You can fill in the joggle in that corner. I have some notes related to that corner of the baffling and additional oil cooler support here:

http://blog.bowenaero.com/?p=392

 

[Rick6a]

Overlapping the Seal

Another way to approach the problem is to overlap the two pieces of baffle seal at the outside corner in such a way as to leave plenty of material on each piece to firmly bind them together with high temp RTV.

 

[Ted RV8]

I overlapped them as Rick shows and then tied them with lacing, loosely.

I wanted them to find their own best position once in operation with the air pressure against them. After running a few times they settle into position and giving the best seal.

If you RTV them together and it happens to be the wrong position for best seal they will always be in that position.

Wouldn't rivet them as the rivet will always be rubbing on the fiberglass cowl. Eventually it will do damege to the cowl.

Ted

 

[Rockyjs]

There is also a strengthener piece that comes with the newer baffle kit that makes this a straight shot across the back. It can be ordered separately.

 

[David_Nelson]

Progress thus far...

Thanks again guys for the help. I managed to get the rubber baffles about 99% done. Just lacking the inlet ramps, some sewing, and of course some riveting.

Rick - Curious as to why you didn't silicone the rest of the corners? The one corner seems to have come out very nicely.

Ted - I was wondering what to use for "thread". I take it you haven't had any problems with lacing and high temps. Correct? I find it odd that AC 43.13 doesn't include a section on "cooling".

Rockyjs - My kit did come with that part. I've decided to do away with it for two reasons: 1) I plan to install a strut from that corner over to one of the case bolts along the centerline of the engine. This has proven to work very well against cracking of the aft left corner for other builders. 2) I want to maximize the height of the cooler in order to maximize the number of cooling fins that are subjected to cooling air. Seems that with the bracket, I'd have to install the cooler lower and share the air with the #4 cylinder fins. There was also discussion on VAF and from I recall the recommendation was to install the cooler as high as possible. The plans also indicate to the same.

/\/elson

 

[Brantel]

Rockyjs - My kit did come with that part. I've decided to do away with it for two reasons: 1) I plan to install a strut from that corner over to one of the case bolts along the centerline of the engine. This has proven to work very well against cracking of the aft left corner for other builders. 2) I want to maximize the height of the cooler in order to maximize the number of cooling fins that are subjected to cooling air. Seems that with the bracket, I'd have to install the cooler lower and share the air with the #4 cylinder fins. There was also discussion on VAF and from I recall the recommendation was to install the cooler as high as possible. The plans also indicate to the same.
/\/elson

You have to be carefull with the cooler much higher than what you can get with that new part Van is now including, the cooler will run into the cowl and could also have problems with the engine mount.

You could still add the brace bar in addition to this part.

 

[David_Nelson]

Hi Brian,

So far the flanges on the cooler are looking pretty good with respect to the engine mount. They many need a tiny bit of trimming to meat the 1/2" clearance spec. I'm also keeping an eye on the cowl - I'll be sure to measure the distance before cutting any holes.

/\/elson

 

[jthocker]

Good point Brian!

David, the Van's new baffle kit is well engineered, both from a standpoint to reduce cracking and efficient oil cooler placement. Beware of INTERNET stories of baffle cracking and poor oil cooling, Van's continues to engineer and improve there products so you don't have to.
3 RV8's on our field with the new baffle kits/ standard oil cooler location, 300 hrs. between the planes, no cracks, good cooling.
Regards,

 

[Steve]

Ours cracked, too

My bud has an o360 on his 6 and I have an o320 on my 9A. Both a/c have Vans original baffle kits and both now have cracked baffles. His plane has 100 hrs and mine has 200. Neither plane does any acro flying.

Here's the DR (discrepancy report) findings:
Both a/c exhibited 2 cracks on the left rear baffle wall. The cracks started where the 2 oil cooler nut plates are riveted to the 1" wide flange. The oil cooler was located per plans, however the nut plates ended up being partially located inside the corner radius causing localized stress points leading to cracks extending approx 1" up and down from the nutplates. It is my belief the cracks were not caused by flexing of components so additional bracing would have been of no use in this instance. The cracks are very fine and were seen with the aid of a very bright LED inspection light. My guess is the cracks happened within the first flight hours.

Corrective action:
Monitor cracks for growth then replace left rear baffle corner assembly with Vans new design when conditions allow/dictate.

Notes for new installations with old parts:
Position the oil cooler as far outbaord as possible so the nutplates are not near the inside baffle radius. Grind the side of the nutplates, if possible. Add a relief hole in the inside radius on the baffle wall where the nutplates contact the radius.