I am still curious about the need to
> be able to disable the waste gate servo.
Maybe some shortcoming in the TCU software..
My thoughts are about the
> delectability of a failure and what remedial actions can be taken in
flight.
> Assuming I don't have a Flydat, how could I tell if the waste gate has
been
> commanded by the TCU to an incorrect position.
Surge should be noticeable by unstable manifold pressure and/or engine power
output.
Secondly, lets assume that
> the TCU drove the waste gate to fully open or fully closed and I was able
to
> determine that this was incorrect, how could I move it from that position
in
> flight. Disabling the servo in this situation doesn't really buy me much.
TCU trouble may not necessarily relate to driving the waste gate to the
stop, but raher to inappropriate pressure/flow rates leading to MP
oscillations. The problem is very well known to jet engine or turbo people.
But in our cars those problems have been caterd for.
According to the Rotax 914 installation maual, in case of surge,
disconnecting the turbo servo should restore stable operation after a few
oscillations.
> I suspect that if the TCU failed in a manner that keep driving the servo
> hard against the stops that it would cause enough over current to trip the
> circuit breaker.
Hmm, IF Rotax people did their homework, the waste gate servo is a real
servo with built-in limit switches
Just my thoughts,
Regards,
Gilles
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