Oil leaking during aerobatics?

tkatc · #1 12-20-2011, 12:31 PM

Ok, I just started doing loops and rolls. I even tried momentary inverted flight but I am probably pretty sloppy. I do not have inverted fuel or oil. IO-360.

I land and my hangar mate says "Holy oil leak!" I said yeah, it seaps some but I haven't been able to find it. (Thinking he was talking about my pesky seep down the nose gear fairing) Seconds later I see what he meant. The pilot's side of the fuse and belly had very healthy streaks of oil going towards the tail. I mean it looked bad!! A little rain probably didn't help it.

I didn't have time to uncowl but I did check the oil which was a quart lower than when I started my 2 hour flight. I checked it just after landing so some of the oil could have been hiding up in the top of the engine but I am very alarmed. Any experiences?

Guy Prevost · #2 12-20-2011, 12:45 PM

Without an inverted oil system, negative (or even zero) g will pump a lot of oil out of the breather tube.

JonJay · #3 12-20-2011, 12:45 PM

Any negative g's will throw mass amounts of oil out of your breather if you do not have inverted oil.

Ironflight · #4 12-20-2011, 12:48 PM

Yup - you can tell how good you are at avoiding "negative-G" by how little oil you have on the belly (unless you have an inverted system). That's why I installed the "Half Raven" system on the new RV-3 - so I can avoid dumping all that oil!

Sid Lambert · #5 12-20-2011, 12:58 PM

You mentioned flying the rain as well. Even without going negative, flying through the rain will make your airplane look dirty in places. I get in the rain about every 200 hours and when I do I have long black streaks in places around the cowling.

tkatc · #6 12-20-2011, 01:04 PM

Whew! Makes sense! Definately pulled 0 to -1 G. Now my heart will stop palpitating a little less than it was while performing the maneuvers. Today was my first loop!

I am dreading pulling the cowl to see the mess I have to clean. Oh well, I'm due for an oil change anyway.

JonJay · #7 12-20-2011, 01:45 PM

Quote:

Originally Posted by tkatc

Whew! Today was my first loop!
.

Strongly suggest some Aerobatic training with a qualified person. Not something to just teach yourself IMHO.

islandmonkey · #8 12-20-2011, 02:24 PM

Also, if you have topped off the oil to full before you do some aerobatics you will lose a lot over the side, as much as a quart if you have been sloppy and gone 0 or negative. Ask me how I know.

Vlad · #9 12-20-2011, 03:39 PM

Quote:

Originally Posted by tkatc

Today was my first loop!

.

and it was looking correct from 1 mile.

By the book. I will get you some oil.

tkatc · #10 12-20-2011, 07:03 PM

I wanted my loop to be "round" vs pointed so I deliberately eased off the back pressure to hold the top of the loop before starting the increasingly stronger pull after cresting over the top. I also remember pushing a little during an aileron roll to hold the inverted position for just a second or two. I suspect the 2 loops coupled with an attempt at inverted flight was enough to let the oil dump all over the place. (I have had some light instruction but it was in a Pitts designed to do ANYTHING)

This was a learning experience as far as not being set-up for inverted flight. I knew I could be inverted for BRIEF periods but I did not know I'd be dumping oil all over the place. Now I know I have to avoid neg Gs. It will be a lesson I wont soon forget!! I will be regretting my mistake as I am cleaning the belly in near freezing temps!