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Baffling Cooling Issue - RV10 FWF Kit

baldcaldwell

I'm New Here
Hello,

I purchased and installed the IO-540 RV10 FWF kit on my Bearhawk 4 Place that includes all of the baffling, oil cooler, etc.

I've flown the airplane over 50 hours now. The engine is now broke in, but I am still getting high CHT temps, especially #6. In cruise, #6 sits consistently at 400 degrees.

I'm wondering if this is because of the 4" scat tube opening to the oil cooler directly above #6.

Have any of you RV10 guys experienced this issue, and what have you done to resolve it?

Just FYI... Below you can see the baffling and the location of the oil cooler direct air port.

(I created a plenum instead of rubber baffling for the top of my engine. You can see my entire baffling project here: https://bearhawk4place.blogspot.com/2019/11/3-engine-baffling-and-plenum.html. )


IMG_1999.jpg



Thanks!

Rob Caldwell
Lake Norman Airpark (14A), North Carolina
EAA Chapter 309
Model B Quick Build Kit Serial # 11B-24B / 25B
YouTube Channel: http://bearhawklife.video
1st Flight May 18, 2021
 
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Hey Rob,
I's Todd. Missed you at Osh but did stop by the Bearhawk booth to look at the 5. Anyway, yes the oil cooler does rob some cooling air, but in reality it's death of a thousand cuts, or air leaks in this case. For example, I'd recommend completely closing off the upper engine mount holes with a cover vs using baffle seals. After that, you need to look at closing off any gaps as you find them to include the seams in your plenum. Unfortunately, there's rarely any panaceas.
 
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Hey Todd. Sorry I missed you.

I did go through and seal as much as I could. (The pic above is not recent.)

You mentioned a cover for the engine mounts vs rubber. Is there a cover available that can be purchased, or, has someone posted fabrication details for such a cover?

One thought I am considering... I wonder if blocking the upper portion of the oil cooler duct opening would help push more air over the #6 cylinder? Slowly increasing the size of the restriction until optimal.

See this pic...
 

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here's one way

FE74FB81-CB7D-4909-97F3-CE7C832AED52.jpg

4BA9C00F-7D21-4B2A-80F3-46A585655461.jpegSlather modeling clay over the upper engine mount ears. Coat with PVA release. Lay up fiberglass/epoxy. Remove, trim to size.
 
Aerosprt

Aerosport makes mount covers.

I have the tcw oil cooler valve on my -10. If I close the valve down a bit, the CHT cools off…but the oil temp rises. My baffling and seals are pretty tight so I am planning on a small diverter mounted on the back baffle to help feed that cylinder. Haven’t installed it yet so I do not have any results to share…
 
Hey Todd. Sorry I missed you.

I did go through and seal as much as I could. (The pic above is not recent.)

You mentioned a cover for the engine mounts vs rubber. Is there a cover available that can be purchased, or, has someone posted fabrication details for such a cover?

One thought I am considering... I wonder if blocking the upper portion of the oil cooler duct opening would help push more air over the #6 cylinder? Slowly increasing the size of the restriction until optimal.

See this pic...

Yes you can buy them but they are crazy expensive IMO: https://www.aerosportproducts.com/product/rv-10-engine-baffle-motor-mount-covers/

Like Bill I simply rolled my own except I did my in fiberglass. I don't recall what I used as a mold but whatever it was I just placed it over the hole with and covered it in-place with duct tape which has great mold release properties and then glassed over that--easy-peezy.
 
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What seals the cowl inlets to the plenum inlets?
.
 

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One other thing to possibly look at is doing a GAMI lean test to see where #6 is peaking in relation to the other cylinders. That info might indicate the need to swap to a different size fuel injector nozzle.
 
Pro tip:

Remove the modeling clay male plugs you built up around the engine mount ears before installing the FG covers you laid up over them :D

Easiest fiberglass project you'll do on the whole plane. No one ever sees it; can be left rough as a cob if you don't feel like finish sanding.
 
Foil tape? Got a photo? The videos don't seem to show any sealing.

Just installed the foil tape recently, when I realized the temps are not coming down after the engine break-in. Seems to help on the front cylinders a bit. Will take pics next time I am with the plane.
 
Aerosport makes mount covers.

I have the tcw oil cooler valve on my -10. If I close the valve down a bit, the CHT cools off…but the oil temp rises. My baffling and seals are pretty tight so I am planning on a small diverter mounted on the back baffle to help feed that cylinder. Haven’t installed it yet so I do not have any results to share…

I have no trouble with my oil temp and is holding consistently at 185 degrees in almost all phases of flight. So I have to think my oil cooler is getting more than its fair share of air from the back of the baffling. This TCW valve appears to have the ability to be controlled from the cabin? Interesting.
 
A cut Greek yogurt cup and some modelers clay works well to create the mold for the engine mount covers. However, if I were to do it again, lots of red RTV filling in the gaps around the mounts would be the way to go.
 
Consider installing a manometer with one open end on the right rear and one on the left rear and see what the "Delta P" is?
 
Hey Todd. Sorry I missed you.

I did go through and seal as much as I could. (The pic above is not recent.)

You mentioned a cover for the engine mounts vs rubber. Is there a cover available that can be purchased, or, has someone posted fabrication details for such a cover?

One thought I am considering... I wonder if blocking the upper portion of the oil cooler duct opening would help push more air over the #6 cylinder? Slowly increasing the size of the restriction until optimal.

See this pic...

Any results on blocking the top portion? I am thinking of doing the same. Another idea I had was to put a smaller dia velocity stack over the opening, since my oil temp is at the lower end (170-180)
 

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My favorite part is the sticker on the flywheel that says "FLYWHEEL". Yeah, I like to label stuff, too. :D

Everybody is bringing up valid points, but it's kinda hard to tell without seeing a recent photo up close. My two cents' worth...
1) You need to seal up every crack that's not allowing air to flow past a cooling fin. Every crack. Where the baffles meat the case, around the inter-cylinder baffles, at the cylinder bases, etc. I had several people tell me this when I thought I had finished--but I was reluctant to accept that advice since I didn't understand how a few gaps could make a big difference. I finally got it through my head, and it does make a difference.
2) I would be surprised if foil tape would adequately seal up between the plenum and the cowling inlets. Most people use neoprene, flexible fiberglass/RTV sleeves, or flexible baffle seal material. It's got to be able to flex a little when the engine shakes. A search on VAF should turn up some good pics of how people are sealing that area.
3) Have you confirmed the ignition timing is spot on? A few degrees advanced can make a big difference. If it calls out for 25 degrees BTDC, you absolutely don't want to be higher than that (i.e. 26 or 27 degrees BTDC would be very bad). Consult with others who are more familiar with that engine, but you may be able to lower that down some...maybe 22-23 degrees BTDC without any appreciable power loss.
 
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