Dennis Lowe wrote:
> Can I seek some advice?
>
> I have been advised to fit a manifold pressure gauge when a variable pitch
> prop. is used.
>
> I am completing the construction of the instrument panel so now is the time
> to make room for one.
>
> Can anyone explain the possible reasoning behind this, and how the pressure
> gauge is used in flight.
>
> Also, does anyone know of a supplier for a fuel pressure transducer.
>
> #333 is a tri-gear with a 912S.
>
> best regards
> Dennis
>
On a fixed pitch prop you can get your power setting (% power) from the
altitude and engine RPM. Since a constant speed prop is an RPM governor,
the tach can no longer be used to set power level. Power level is then set
based on manifold pressure at a specific RPM setting, for example, on my Great
Lakes 55% power might be 2000 RPM at 21" MAP at 4000 ft., with 7 gal/hr
fuel flow. Your operator's handbook would have lists of power settings
(%power)
at various altitudes, RPMs, and the associated MAP and fuel flow.
I bought the Allegro fuel totalizer which also includes tach, manifold
pressure,
and fuel pressure. You might call them for the info fuel pressure transducer,
or
maybe get the whole instrument. This is the unit that Kim Prout uses.
Their website is at:
http://www.allegroavionics.com/
Terry Seaver
A135
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