DakotaHawk

DakotaHawk

Well Known Member
Here's my ugliest RV picture...

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I was getting some aerobatic instruction this afternoon. We were doing cuban eights and I kept having trouble keeping my plane on a heading as I rolled out. My instructor kept telling me to unload the elevator before I begin my roll, but I wasn't getting it.

After making five or six attempts, I was trying to unload the elevator, and pushed it too hard. Ended up with -0.6 G's, and spit about two cups of oil all over my windscreen, firewall, and fuselage.

Took me a couple of hours to get most of the oil wiped down. I'm guessing it will be weeks before I get all of it out of the nooks and crannies.
 
Hmmmm. ..

...where do you suppose the oil exited? Looks like the oil filler cap was left off because with a downward facing blowby tube, it should fill up during negative G's and then smear the belly as you go right-side up.

Best,
 
Been There!

eh009us said:
Ouch . All jokes aside and mess not withstanding, I like the color scheme...
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I have done the same thing. Fortunately, it was in a friend's RV, and he was the one that unloaded the wing. So, it was a mutual job of cleaning.

My wife did not even notice the oil, she really likes the maroon and white, and the scheme that you chose.
As far as the oil, just think of it as corrosion control and press on!

Good Luck!
 
Yep - I've done this too (though not quite as bad), when a spin recovery moved the stick slightly too far forward.
 
Oil exit

pierre smith said:
...where do you suppose the oil exited? Looks like the oil filler cap was left off because with a downward facing blowby tube, it should fill up during negative G's and then smear the belly as you go right-side up.
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I, like Pierre, am wondering how the oil got that high on the airplane. Mine ended up exclusively on the belly and lubricating the tailwheel. :rolleyes:

John Clark ATP, CFI
FAA FAAST Team Member
EAA Flight Advisor
RV8 N18U "Sunshine"
KSBA
 
pierre smith said:
...where do you suppose the oil
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My instructor and I wondered the same thing. First thing we checked was the oil filler cap - found it secure (and well lubricated!)

So tell me if this makes sense...

I pull up through the first half of a loop, so now I'm inverted. I neutralize the elevator and accidentally push too hard, causing -0.6 g's. (the oil breather fills with oil). Still inverted, I correct my mistake by pulling back on the stick. This puts positive g's on an inverted plane and the oil drains out of the breather. As soon as the oil exits the breather, gravity takes over and it heads for planet earth. Unfortunately, my plane is still upside down so the top of my plane gets in the way of the oil returning to earth. And then I roll upright to complete the botched maneuver.

I was only negative g's for a second, and it took only a couple of seconds to correct and finish the maneuver, but I think that was plenty of time to evenly coat top and bottom of my plane.
 
If your breather tube doesn't go down far enough below the belly this can happen. Once oil gets in that breather line and the engine is running it will pump it out faster than you can put it in. I've done this but no where near the amount you spewed. You should view this as a badge of honor! Clean it off, laugh and go at it again.

Yes, an inverted oil system would prevent this.
 
Eww! Looks like an Unlimited Reno racer after a hard race!

Which reminds me, I wish I was there today! :(
 
Belly oil

RV8R999 said:
what about an oil separator in line with the breather?
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Probably not much help, the average separator is for dealing with oil mist, not a slug of oil. In my case, the oil passed through the separator and stayed on the belly due, I think, to the position of the end of the breather. The tube terminates aft of the firewall, in the "tunnel" on an '8.' Not a big deal really, look at it as an anti-corrosion treatment. :)

John Clark ATP, CFI
FAA FAAST Team Member
EAA Flight Advisor
RV8 N18U "Sunshine"
KSBA
 
Different take

At fist glance I thought the pilot opened the canopy on rollout and the passenger...you get the idea.
 
I lost a whole quart one time

I thought a broke an oil hose. It came out around the cowl and all over the bottom of the fuselage. It made puddles on the ground. It's amazing how much surface a quart of oil can cover.
 
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I've made a couple of flights after lubricating my rivets, and I'm still wiping up tiny runs that are sneaking out of nooks and crannies.

After letting the plane sit overnight, I checked the dipstick and found I had lost about 1/4 quart of oil. It had only gotten on the right half of the top and bottom, and most of the right side of the plane.

My instructor was unable to see clearly out of his side of the windscreen, but I was able to see fine. He wanted to keep flying... I wanted to head back to the airport and start wiping down the mess!

Things that I KNOW...
There are no broken oil hoses.
The oil filler cap was firmly in place.
The stuff on the fuselage side is definitely OIL, not the contents of my passenger's stomach!
 
I think we have all done the same thing. Mine was a botched humpty-bump, however as others have mentioned the oil did not make it that far up the side of my airplane.
 
Yup!

Master Designs said:
Sorry if this is a stupid question, but would an "inverted oil system" prevented this from happening?
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Yes, inverted oil systems are designed to keep the oil on the inside the plane, not on the outside. Its like the old Wesson Oil commercial, it all comes back except thiiiis much.:D:D:D
 
Oops! I did it again...

Jamie said:
Mine was a botched humpty-bump,
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More aerobatic training today - I've got about 5 hrs total so far - and my instructor was showing me a humpty-bump. As we came over the top, things got pretty light, and the G-meter showed -0.1 g's pulled!:eek: Sure enough, the oil sprayed back over the right side of the plane.

I've looked at the inverted oil systems, but I think that might be overkill for the type of flying I want to do. I'm not interested in adding five pounds and $1500 dollars to the firewall of my RV-7.

I saw an air/oil separator on an RV-6 and really liked this installation. (The black hose comes from the crankcase breather, into the separator, and then out of the black hose, up and over and down to exhaust near the engine exhaust pipes. The separator drains into a small tin tank (with a 1 pint capacity) located lower on the firewall.
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I'm open to suggestions, photos of your installation, etc.
 
Scott, check out Ron Schreck's setup as described in this newsletter. Works perfectly for Sportsman level acro without a full inverted system. He's one of I think two who actually flew an IAC contest in an RV this year. Would be nice to have one more!

http://www.iac19.org/images/DAF_APRIL_10.pdf

BTW, if you're going to do a positive G roll during a half Cuban and stay on heading, you will need quite a bit of opposite rudder during the first 45 degrees of roll before reducing it and transitioning to a good bit of top rudder after passing through knife edge. You're fighting the lift vector of the wing all the way around.
 
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Thanks for the link to Ron's setup and the advice about rudder/cuban 8s. I'm going to give Raven a call tomorrow to start gathering info about their "sump only" setup. Their website says that the setup is pretty standard for the light aerobatics that I would like to do.

I've seen the effects of the rudder while doing cuban 8s, immelmans, and split s's. Still trying to get the sight picture figured out in my head when I'm upside down. Everything seems out of place, and I come out of the manuever heading somewhere completely away from where I thought I should be heading!:rolleyes:
 
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