12
    We where having serious oil problems the last few times Dan flew it.
    The last flight we lost a full gallon and a half over board. Despite
    that it took only 1 minute 47 seconds to get to 10k and best the
    record.

    The oil pressure started at about 120 psi and by the time Dan got to
    10,000 feet it was down to 50 psi. As soon as he leveled off it rose
    back to 120 psi. I suspected pump caviatation as the intake was
    about 3 feet below the oil pressure pump when the airplane had a 45
    degree nose pitch up angle.

    The two problems were not necessarily related.

    One of the fittings on the tank, being used for the vent line, had
    damaged threads. Somebody cut the vent hose fitting nut down to
    compensate. That was a new trick on me. No matter your age and
    experience there is always something  new to learn :-)

    It worked as long as it was tight but it did not take much to loosen
    it. I believe thats how we got a half gallon of oil in the bottom of
    the fuselage :-)

    It just so happened I had a steel -12 AN fitting so I screwed that
    on and it cleaned up the aluminum threads.

    It is 1" & 5/16" by 12 threads per inch which just so happens to be
    the same size nut that holds the wheels on a tractor trailer truck
    :-)

    You can get steel dies in that size but  they cost over $50.

    Paul Lamar

   Paul,  Hydraulics are a real problem if the suction hose is undersized.
   Years ago when building Ag tractors it was specified that I Install a 2
   inch suction hose and also a header tank to prevent cavitation. There
   are a few options but all involve alterations which are time consuming
   and the cost involved.   Good luck as usual,

   Neil Unger. In Oz

   Neil owns a 650 HP tractor about the size of a house :-)
   He should know.

   Thanks Neil.

   Paul Lamar



  As you know I am not super familiar with rotarys and I don't know how your tank or breather is configured,  but I wonder if your scavenge pumps can get the oil to the tank but not the air out of the engine so maybe it's possible depending on how you have it plumbed that it's blowing lots of crank case pressure into the tank along with high pressure air.

That is if theres no crankcase breather on the engine (or e-shaft case breather?) and airrating the  oil and  blowing air around and making a mess in there.  Just had to put a conventional breather on my buddies twin turbo lsx car cause on high power it would do the same thing so know it's a conventional breather and the scavenge pumps take oil to the tank without ever being able to put a vacuum on the crankcase which is better than before it was blowing out the relief and causing very very similar issues. After the breather he has gained oil pressure on high power.


I am interested to see what you find out, good luck and that last flight was impressive.
Thanks, Jacob Sturges

Yes! You are absolutely right. I am working on that problem as well.
The rotary is notorious for that problem.

See if you can get down to Seven Stock tomorrow. You will be amazed.
I'll hang around the Mazdatrix booth,

http://sevenstock.org/

Paul Lamar

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