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Burp all the time?

E

Ex Bonanza Bucko

Well Known Member
As a newbie I have a lot to learn so this is my next question after seeing the Rotax Owner videos and reading all of your posts which have been very, very helpful:
So...if A.) I am the only pilot to fly the airplane; B.)There is no puddle of oil under the engine and C.)If I changed the oil two hours ago on a new engine and I'm SURE the engine is not using oil, Then:

Is it necessary to Burp the engine to check the oil before the first flight of every day?

Thanks,
EBB
 
After flight

I normally burp the engine after my flights. Doing it this way only requires turning the prop through about 4 or 5 times (much less than with a cold engine). I then check the oil. This way I know it is good for the next flight, :) unless I see a pool of oil on the floor. :(
 
If you don't burp the engine you will get a lower than actual oil level due to the oil sitting in the engine, so you might over fill thinking you need oil. There is no mechanical reason to burp (i.e. the engine isn't damaged if you don't).

I used to flail away pulling the prop around until the instructor at the ROTAX course showed me that if you pull it slowly and pause when you feel compression to let the air leak by the rings you'll only have to go through 3 or 4 revolutions to get the burp.
 
I totally agree with others.

Burp the engine after flight (as said a few blades will do it) - s l o w l y, holding it on compression. We always get it to burp twice, then check the level.

Pre-flight if the oil level is on the flat of the dip stick then you're good to go. The flat level is only 0.45 litre so ex-Lycon drivers have to be trained not to throw in a whole quart (apologies for mixed measures).
 
Dear Johnny Stick:
Thanks you so much for you kind criticism...now go bend you stick someplace else:)
CFI, Instrument, Aeorbatic Instructor and 5000 hours in every small plane made since 1930.

EBB:)
 
I usually burp it after the last flight of the day too. What I have noticed though is that measuring when the oil is hot shows a vastly higher oil level than when the engine is cold. So, now I re-burp before the first flight and see that it is sufficiently above minimum before taking off.
 
I suggest checking the oil in the tank. If its below the minimum, then burp. As others have noted, burping always increases the oil level.

The 912 series used to have a lower range on the dipstick. It was increased due to issues related to foaming in the oil in case the wrong oil was used (due to common engine / gearbox oil). So the minimum level on the dipstick is pretty conservative.

TODR
 
My neighbor who has a Piper Sport aircraft experienced a hydraulic lock in his engine during preflight. Admittedly, the plane had not been flown for a month or so but any attempt to start it would have resulted in significant engine damage.

The oil pump gets it supply from the reservoir and if it's all drained into the engine you will have a dry (expensive) start. It's important to verify that there is at least some oil in the tank before start even if it was checked after shutdown.

Mitch757
 
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Mitch,

I've had hydraulic lock in the radial of my Yak-52 due to oil in the bottom cylinders, but I don't see how that's possible in the boxer type engine like a 912. Maybe the location of the oil tank n the Sport Cruiser is an issue, but I don't see how hydraulic lock could occur on a RV-12. I have an open mind if someone can explain how it could happen!

Rich
 
Hi Rich,

I'm not saying it could happen on a 12, just that it's important that enough oil is in the reservoir to prevent a dry start. I think the tank is mounted a bit higher on the Sport Cruiser relative to the engine. Another neighbor with the same type plane hasn't had that problem.

The hydraulic lock was real in this one plane though.....oil was drained out of the lower spark plugs...just like a real radial...

Mitch
 
I burp the engine on the first flight of the day. If I park it, come back and there's no puddle, I don't burp it again.

Once I did return with a significant puddle, so I burped it again. Turns out, it wasn't my puddle. Whew!
 
Mitch,

I guess I'll file that hydraulic lock info away in case I ever encounter a stubborn prop. Prior to your post I never would have considered that possibility.

I used to believe you couldn't hand prop a 912, and that was wrong too.

Live and learn!

Rich
 
The hydrolock came more from years gone by. It was from kit designs like Kitfox and any others with a high oil tank mounting. It came from the old Rotax oil filter design. Major improvements in the filter design and educating builders have come a long way. The other issue is some people still have some of the old filters lying around. If using the proper oil filter and the oil tank height is withing mounting limits it would be extremely rare to see hyrolock issues any longer. That said I know there are still people out there using car oil filters. maybe years ago they were close to the same as a Rotax, but those days are gone.
 
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