X-Mozilla-Keys:                                                                                 
Jeff Spitzer wrote:

David Carter wrote:

- but I don't believe there is any safe time to
allow pinging.  As for Detonation:  By definition, we are talking about
DESTRUCTIVE power blasts that IMMEDIATELY starts to damage something
(pistons and valves in piston engines, apex seals in 13B).  I've never
had detonation in a car, as far as I know - only pinging.

There is no such distinction.  What you are calling pinging is ONLY called
detonation (possibly pre-ignition which is different) in the engineering
literature.  The distinction you made about severity is true but not easy
to define analytically.  The sound you hear is from the shock waves of the
explosion exciting the chamber walls.  When the shock wave occurs early
enough or severely enough to strip  large areas of the thermal boundary
layers that protect the walls that's when you see burning of components.

Ah so. That is why you see those pits in aluminum cylinder heads and
exhaust ports. The inspection procedure for a B29 R3350 engine was
to check the exhaust ports for pitting. If so the engine was
changed out. Jeff Ackland saw the same thing in the Chev big block
V8 aluminum cylinder heads on the engine he took out of the Ledgen.
He probably did not hear it detonating.
 
Fortunately the Mazda rotary has a steel and cast iron lined
combustion chamber. PL

 I
think in a "pinging" situation the quantity and timing of the *detonation*
is within the capability of the components to deal with the localized
increase in heat flux.  After all, if it weren't you'd know it by now :-)

Jeff Spitzer

The Aircraft Rotary Engine Newsletter.              Powered by Linux.

http://home.earthlink.net/~rotaryeng/            http://www.linux.org