Lynn, got any idea what hp you are
 > developing at 6000 rpm?

I have no clue what that might be. I suppose there is data somewhere on that.
The Lemans engine had to perform down there because of the huge speed
disparity between the slowest corners and the longest straight-aways. The
more typical power band of 8,000 to 9,700 RPM would leave you way slow off
the corners because you have to tune for the straights. I was thinking that
just using the Lemans closing event might leave very low torque below 6,500.
As in the case of an emergency go around with the RPM below 4,500 perhaps.
But with the PRSU this would only be an instant of hesitation. It looks like
they put in as much timing as they could get away with, without screwing up
the bottom end torque. I would think the airplane case would be just a bit
lower than that. Maybe 6,500 flat out and 5,800 cruise, or there about. So I
would hold off on the late closing just a bit. Maybe 1/4" short of the Lemans
timing.
You can go back in and extend the closing event later if you need more top
end. I think anything you do, even a very mild Pport will amaze you. One good
thing is that both periphery port and bridge ported engines seem relatively
insensitive to closing events. They lose bottom end rather badly but we don't
need no stinking bottom end!!

I bought some fuselage parts from a guy in California, so a new adventure
will begin this spring (between racing stuff). Then in a year or two I will
build the 13B that will make the world tremble. Or, maybe not. But pretty
good at least. I will also photograph every step along the way, instrument
the heck out of everything, and make it all available to everyone.
There will be no heating problems. I might have to eat those words, but I
don't think so.
Lynn E. Hanover

 
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