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Message
Do you have an oil/air separator
returning oil to the sump? If not, I suspect the "oil usage" you are
seeing may just be oil lost in the blowby. In my early days with plugs up
(before I built a new sump), I would get foaming oil out the dip stick when I
exceeded 5000 rpm so I built an air/oil separator. Later I discovered that
with the new sump keeping the oil level in the block next to zero eliminated the
foaming. However, I can imagine that at 7000 rpm the oil mist and foaming
as the cooling oil pours (or is slung) from the rotors probably suspends a lot
of oil in the air which could get blow out.
FWIW
Ed
This
is interesting. When I was flying the rev-1 version, I started with just a
small on the dipstick vent. This was just one of those old PVC air filters
that I picked up at an auto parts place. You could see that it got misted
with oil, and accumulated a few drops in the bottom, but that was about
it. Eventually, I got around to installing a vent line that ran down to
the exit of the cowl, which worked fine for a while.
After
one particular flight, I noticed that the belly was coated with oil, all
the way back to the tailwheel. I thought it was due to the fact that
I ran the engine harder than usual, and did a little more maneuvering on that
flight, and I'm sure those things were a factor. The real culprit seemed
to be the placement of the vent tube exit. I had changed something
prior to the oily flight, and had to reposition the vent line. It's new
position seemed to be in a location that must have caused a suction on the
tube, which helped the oil escape.
Next,
I used a normal size line from the dipstick vent, which is inserted in a larger
diameter clear hose. This is a very loose fit, to allow air to vent
between the tubes. The bottom of the clear tube has a valve, which stays
closed in flight. This allows me to capture, and monitor the oil
loss. I kept this arrangement in the rev-2 configuration, primarily to
keep from dumping oil on the hot muffler.
I have
suspected that running the oil level on the high side was also part of the cause
in loosing oil from the vent. That's one of the reasons I wish I had
extended my oil pickup tube to make up for the engine mount plate.
Hey Fred, there's another
product you can sell. It would be easy to make a spacer to lower the oil
pickup, and supply it with longer bolts.
Cheers,
Rusty
(company van being picked up by the fleet dept
today)
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