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What I'm trying to say is that testing for the wrong things or testing under the wrong conditions can lead to conclusions that have no meaning or importance to the issue at hand. The point of my question is this: if everyone flying a rotary is finding unburned premix oil in his crankcase oil, is this oil really burning? Is it likely that some percentage of the oil is burning away completely with no residue & the rest is completely unaffected by the heat & is swept into the crankcase? Assuming that is what's happening, then what part of PL's oil from skillet test was unaffected by the burning & where did it go? IIRC, PL heated the various oils to somewhere around 500-600 degrees for his test. How was this temperature selected for the test? Is that the surface temperature of the rotor housing & rotor? Is that the combustion temperature? (Obviously not.) If combustion temperature is, say, 1800 degrees, why wasn't the test done at that temperature? Would the residue be the same if the oil was cooked to that temperature? Would the residue be the same if the skillet was sealed & raised to combustion pressure before cooking?
I wouldn't pretend to have the answers, but after 15 years of trying to absorb everything I can about homebuilding aircraft I can say that if we ask the wrong questions we aren't likely to get the right answers.
If a problem exists for which there is no solution, it makes sense to methodically search for a workable solution. But if a solution has been empirically proven to work, as is the case with Tracy's use of MMO for hundreds of hours, does a 'test' attempting to show that it doesn't work make any sense at all?
It's my understanding that Dave Atkins is still using crankcase oil injection in his RV-6. Street rotaries carbon up, but they are operated at average power levels of 15-30 hp and most get driven in city traffic with long idling at traffic lights, etc. Piston engines driven in these conditions carbon up also. Piston engines driven almost exclusively on the highway (still low power levels but little idling & stop-&-go operation) rarely have 'carbon' problems. Do rotaries driven on the highway have carbon problems? Anybody out there that's got 150k miles on a stock, highway-use-only RX-7?
I'm not pushing MMO; I've never even opened a can & poured it in an engine (or gas tank). I am in favor of methodically searching for answers & understanding that "Better is the enemy of good enough," as a writer for a prominent computer magazine frequently points out.
Charlie
Bulent Aliev wrote:
Something was gumming up the seals in the car engines? The racers started
mixing the 2 cycle oil and had no problems.
On 11/20/04 11:28 PM, "Charlie England" <ceengland@bellsouth.net> wrote:
Is burning oil in a skillet relevant when seemingly unaffected 2 stroke
oil ends up in the crankcase? Might it be that the oil isn't burning at all?
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