Acro's Making a Mess

Did a few loops today in a non-inverted system RV-8. I was trying to maintain positive g all through the loop, but obviously on at least one of them I was unsuccessful and the belly had a small amount of oil on it which came from the breather.

Other than going to an inverted system (which I don't want to do), is there a way to minimize the amount of oil that will dump overboard during casual aerobatics?

I was spoiled by the Christen system in my former Christen Eagle II.

Thanks

Half-Raven

Search for the "Half-Raven" thread. Two-thumbs up.

Run at 6 quarts, pay attention to your aero's and buy a padded creeper trolley, some spray cleaner and paper towels.....

We have the Andair Oil separator and still get belly puke when being a little spirited.

I always know when I will need to clean - it's the 'correct' half cuban's, the hesitation rolls and most spectacularly when I screwed up a hammerhead and push humpty'd off of the top - not good.

Next one will have a Raven system.

I'm goign to watch this thread for any and all ideas - I am pretty much at the point on the -3 where the full Christen system might be crammed in, but will make maintenance such a nightmare that it is going to come down to what is "reasonable" (versus what is "possible"). Half-Raven from what I have read, still needs an accumulator if you really want to lubricate at zero (neutral) G.....and those things are BIG!

I have never been a huge fan of separators, but if they reduce the mess by a little bit, then maybe that's a poor-man's answer. Mike - do you think it makes any difference at all over a straight breather?

Paul

Link to the Half-Raven thread

Have a look here:

www.vansairforce.com/community/showthread.php?t=51286

Hope it helps,

Dominik

My exhaust from Sky Dynamics has a fitting for the crankcase vent in the exhaust collector. Any oil is burned in the exhaust stream. Either that or run the vent tube to the tailwheel like my Pitts. That way if you do enough acro you won't have to lube your tailwheel(ha,ha)!

Ironflight said:

I'm goign to watch this thread for any and all ideas - I am pretty much at the point on the -3 where the full Christen system might be crammed in, but will make maintenance such a nightmare that it is going to come down to what is "reasonable" (versus what is "possible"). Half-Raven from what I have read, still needs an accumulator if you really want to lubricate at zero (neutral) G.....and those things are BIG!

I have never been a huge fan of separators, but if they reduce the mess by a little bit, then maybe that's a poor-man's answer. Mike - do you think it makes any difference at all over a straight breather?

Paul

Click to expand...

Paul,

Nothing says the accumulator has to be on the firewall. I have seen them in the tail of a Pitts! All you need is a bulkhead fitting on the one oil line coming from the accumulator and you can put it anywhere you want. It's functionality is not diminished by a longer feed line.

ronschreck said:

Paul,

Nothing says the accumulator has to be on the firewall. I have seen them in the tail of a Pitts! All you need is a bulkhead fitting on the one oil line coming from the accumulator and you can put it anywhere you want. It's functionality is not diminished by a longer feed line.

Click to expand...

That's a good point Ron - thanks! Still....at some point, I have to consider weight trades....piping the breather out to the tail with a lightweight tube might be a good answer. So has the accumulator solved any surge issues at the Zero-G point?

Thanks for the tips guys. I was kinda eyeballing the Andair system but it looks like Raven might be a better choice. I think I'll try the 6 qt. suggestion first tho.

The separator takes care of a reasonable amount.

That said, we are still running fairly full on oil as the motor has only done 30 hours from new.

I know when I will get belly oil and it is because I am at negative g for a little too long.

It only has a pint or so capacity, it can't replace an inverted system.

Once we run lower levels I expect less oil on the belly.

Its location would lend itself to being replaced by a half Raven system which may be a possibility.

Biggest irritation thus far is a weeping rocker cover. Silicone gasket, refitted it, carefully torqued but still drips annoyingly.

Have now replaced it with a new one, installed dry and clean - will see what happens - airplane down for Dynon fix and HS34 install.

Ironflight said:

Half-Raven from what I have read, still needs an accumulator if you really want to lubricate at zero (neutral) G

Click to expand...

Hey Paul,

I did not install the accumulator. The Half-Raven, without that, solves the problem of oil spilling out in brief zero/negative G. The accumulator, of course, allows for a little more zero/neg G time. I figure I can always add the accumulator later, but so far I'm happy without it. The belly is clean.

dhall_polo said:

Hey Paul,

I did not install the accumulator. The Half-Raven, without that, solves the problem of oil spilling out in brief zero/negative G. The accumulator, of course, allows for a little more zero/neg G time. I figure I can always add the accumulator later, but so far I'm happy without it. The belly is clean.

Click to expand...

Thanks Don - justthe kind of input I was looking for. I was originally thinking half-Raven, based on Smokey's excellent thread that was referenced earlier. Then a while back, this brand-new Christen system came up for sale at a price I couldn't pass up, so it went on a shelf. Now I am finding that it is just going to be way too tight....if Junior was going to be a dedicated, no-compromise aerobatic machine, I could make it work. But I want something we can maintain without pulling the engine to tighten hoses....

Paul