----- 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