You all have to remember that Ed has a knack for finding and exploring all possible failure modes - known,  unknown, and yes, even the impossible :)

Something that no one has memtioned is the gears (end housings/rotors).
Also rotor bearings/e-shaft clearance.
What's the consequences of out-of tolerances here?
I just can't see that a bit of wobble of the apex seals in their grooves could cause a seal to break.
Also, how could you have such excellent compression with worn seals/grooves?
Sounds more like a fluke or foreign object to me. Any chance that some carbon build-up near exhaust ports could break loose and get jammed between seal and edge of exhaust port?
Any telltale on the rotor housing as to where the seal broke?
Did you *thoroughly* inspect the four sparkplugs? Any piece of metal or porcelain missing at all?

Finn

Ed Anderson wrote:

Well, George, I would not  take the conclusion that far.  We have folks flying with several hundred more hours than I have with no apex seal failures.  In fact to the best of my knowledge, I am the only one I am aware of other than Chuck Dunlap who's rotary engine swallowed a 1/4" dia steel bolt (it was retained - so we know) to have an apex seal failure in an aircraft.  However, I do believe that folks need to be more aware of the true condition of their used engine components - I know all probably did was look at it and not seeing any obviously defects or dings said - "good to go!"

 

As you know, Leon is convinced my apex seal failure was also due to foreign object ingestion - I certainly can not prove it was something else (like the apex seal slop)  although I don't believe a foreign object  to be the case - belief is not a fact {:>). 

 

 

Ed