When using 2 engines together with a common power output is there a
   simple way  to assure that both engines are contributing equal power?
   I can imagine that one or the other could be doing more work even
   though they both are running at the same rpm (obviously). I'm thinking
   of using 2 of the smaller available rotary engines on the
  helicopter,  but my question could apply more broadly to any engine
type.

   John McEverett

 "is there a simple way  to assure that both engines are contributing
equal
power?"

Same problem exists in EVERY multi-cylinder engine.

brian gochnauer

That suggest a simple way to do it is compare EGT's.

Paul Lamar

You would probably be much better off comparing CHT's.  EGT's are only
an imaginary number.  The EGT probe sees about nothing interesting 3/4
of the time because the exhaust valve is closed most of the time during
the intake, compression, and power stroke.  During the other 1/4 of the
time there is exhaust flow.  The measured temperature in the exhaust
manifold varies according to the configuration of the manifold.  Same
thing as the problems with pressure variability in the intake manifold
depending on several variables.

See http://www.sportaviationonline.org/sportaviation/201010#pg89 for a
nice article on the subject.

Mark LaPierre

What exhaust valves? :) We don't have no stinking
exhaust valves :) Normally people don't install
CHT's on rotaries with at least one exception but I advocate
and  maintain it is still a good idea. They just monitor coolant
temp which is common on both rotors.

Now for two engines you could monitor coolant temp but
there could be significant differences in the two separate
(if used) cooling systems.

Paul Lamar