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----- Original Message -----
From: "Jim Sower" <canarder@starband.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Wednesday, October 30, 2002 7:44 PM
Subject: [FlyRotary] Re: interesting discussion on intake temp andfuel
delivery.
<... I think it is a mistake to be pushing the envelope too far on boost
...>
Agreed. My purpose for boost would be: a) the suppression that turbo
charging
provides; b) to have 35" - 37" available for takeoff; c) to be able to
"normalize" at altitude and get my 30" at 10,000' or 15 000'. That would
buy
me a LOT of cruise TAS.
Fuel requirements are dependent on *mass* flow, and there's no accurate
way
that I am aware of to compute mass flow without a temperature input. RPM
and
MAP will work acceptably on a standard day because you assume standard
temperature(s). But mass flow calculations will become increasingly
inaccurate
as inlet (to the manifold or combustion chamber) temperatures depart from
standard conditions. One might argue that the errors are manageable most
of
the time, but as soon as you start boosting, accuracy goes to hell in a
hand
basket if you don't accurately compensate for your inlet temperature.
Did I understand Ed's post correctly when he said that Tracy's EC2 has air
temperature compensation on side A but *not* on side B? I'm wondering why
would that be? Seems it would make for vastly different programming of
the
processors.
Feeling a little lost here .... Jim S.
37" would be a safe level to use.
The B controller is primarily used for backup only. The temp sensor on "B"
is not used to eliminate another possible source of failure. If you find
yourself in need of a backup and the mixture on B is not optimum due to high
or low air temps, simply adjust the mixture control knob to suit the
current conditions.
Tracy
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