On a quest for the elusive "Dry AeroVee"

[Bryan Cotton]

Just flew for an hour. Much less oil on the belly. Seems like it is not coming out the breather but all the other various leaks. I noticed some oil on the bottom hinge line. I tried to check the oil level when I got back, but when the oil is clean and hot it is very difficult to see the level. I think it runs down the dipstick.

[Bryan Cotton]

I'm declaring the air-oil separator I installed a bust. The prop seal was leaking oil. Much more resistance to blow through the separator and plumbing as compared to a hose. I went to the stock Aerovee setup and will try tomorrow.

[Bryan Cotton]

Well, the stock setup was a bust. Flew for an hour this morning and oil all over the belly. Previously I had fabricated and riveted a baffle onto the breather cover, and that has been removed.

Regarding the can, I think David A. had it figured out:

Far more important, the bronze filter looks like it will effectively become a cork when covered with a small bit of oil.

I am going to rework the can and remove that filter. Then I'll do the breathalyzer test on it to verify that it isn't a big restriction.

Edit: Here is a picture of the nifty baffle I made. It made essentially no difference.

[Bryan Cotton]

Try 2. First I filled a 1/2" 6061-T6 tube with sand, annealed it, and bent it thusly:

I bored out the hole to 1/2". It was pretty close to that. The tube goes below the disc and puts some swirl on the air-oil mixture.

The scrubbers are right out of the Tony Bingelis playbook.

I had enough time to complete this and get the cowl off. Next chance I get I'll install it and fly it.

And another note - when I blow through the inlet there is pretty much no resistance. At least right now. We will see what happens in use once oil gets involved.

I weighed this with my mounting hardware attached. It was about 1.125 lbs.

[Bryan Cotton]

0.9 today including a run up to Vne. There was a little oil on the belly and some evidence of oil coming out the hinge line. The prop shaft felt dry-ish when I put my hand in there and visibly the oil level looks about the same. Seems hopeful.

[Murray Parr]

Bryan,

how many hours are on the engine? I wonder if the rings haven't seated yet and perhaps you are getting too much blow by. A leak down test might provide you with some useful information.

[Bryan Cotton]

I've got 15 or 16 hours so far. I've not been having temperature issues and per the manual I've not been babying the engine at all.

[Bryan Cotton]

I haven't found it yet.

The filter seal pushed out on startup.

I took the filter apart and it looked ok. Not sure what happened here.

Technically the Aerovee stayed dry but the airplane and ramp did not.

[karmarepair]

My guess is cold oil and/or a stuck relief piston spiked the start up oil pressure. Think about the Gene Berg full flow cover with a built in relief valve if your plumbing will allow it.

[gammaxy]

Oh man, what a mess. I've read about this happening several times on this forum and probably the yahoo groups before. Hopefully after your example people will either stop doing it or find a better way. Maybe someone with hundreds of hours of reliability that's different from this historically and predictably bad method will share their installation.