After some very short flights I have finally gotten N120EJ up for a 46 minutes
flight last week. Im still having some heating problems, but am getting closer
to solving them. Bud Yerly, Jim McCormick, John Lawton, Jim Puglise have been
a big help. I knew when I bought the Jabiru that I'd have heating problems,
but for the 10K that I save by buying the Jabiru I figured I could do a lot
of modifications to the cowl and engine if need be.
One area is the plenum chambers for both sides. I have the type with the spark
plug wiring and CHT wiring running inside. The first modification was to the
plenum chamber. There is not a lot of information out there for installing the
baffles in the plenum. Bud recommends not using any, but I had installed some.
I had to cut these out completely and my dealer, Jim McCormick, said I had
installed them wrong. I then installed three dams across both front cylinders
and mid cylinders plus a 1 dam over 5 & 6. I have since cut these down to
1/8" on the front two cylinders on both mid cylinders. I have 1/2" on the two
rear cylinders. These are vertical to the air flow. Not sure why, but thats
what Jim McCormick recommended. I have also installed the inter baffles that
Jabiru stated that I did not need. I have also wrapped a piece of aluminum
around 5 and 6 to get more air moving across the fin area.
I have four inch openings on the Canadian Cowl that I'm using. I found out
after
I installed them that John Lawton had gone to five inch openings. I have
modified
the shark tooth or NACA duct for the oil cooler. Trying to figure out
a method of using this NACA duct and keeping the oil cooler attached to the
engine
had been a real challenge. I think I have modified this one piece five
to six times. I have what is called an 8 bar oil cooler. It is about the
closest
thing to aviation type oil cooler. The last modification was wrapping the
oil cooler with duct tape and waxing it so I could make a fiberglass mold.
Once I had the mold made I placed it in the lower cowling and designed it to
be glued into place so air could not escape around it, but had to go through it.
I built a duct behind the oil cooler as recommended by a good friend and that
has help a lot. I noticed after doing all this work that my cowling had dropped
I flew it this way and the oil temps came down and stayed down. I then
went back and figured out what was causing the drop in the cowling and fixed
that, but that caused the oil cooler opening to move away from the oil cooler
about on the bottom. I flew it that way and sure enough the temp came up.
One area that I might work on is making a cowl flap for the oil cooler duct.
Not
sure how to do it right now. It will have to be part of the airframe and not
the cowl. More on that later, if and when I do it.
Im planning on putting a raised ring around the openings for the air intakes.
Right now this is a flat area and I have been reading some data that shows that
I can increase the flow into the plenum chamber by doing this. There is a dam
on 1 & 2. I have made a ramp so that the air will flow up and over these dams.
The temps on 1 & 2 are good right now, but the ramps may cause them to run
hot.
One thing that has helped a lot is the black box viewer on the MGL Odyessey II.
It gives me the data in one second packets. The air temp, altitude, RPM,
manifold
pressure, oil temps, oil pressure, CHTs, EGTs, etc. It is a great tool.
Well, it time to go back to work on the Europa/Jabiru.
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