This has caused me to think a bit.
The Europa builder=99s manual shows the fuel going from the fuel
selector to the electric fuel pump and then to the engine=99s
mechanical fuel pump. Is that how it is set up?
If so, does the fuel get pulled through the electric fuel pump by the
mechanical fuel pump when the electrical fuel pump is turned off? That
seems like it would cause variation at that point.
Various aircraft builder=99s books from the EAA show a parallel
system for low-wing aircraft. Those diagrams make sense to me. In other
words, they show the fuel being provided by a parallel fuel system, with
fuel lines going from the fuel selector to both 1) the electric fuel
pump and then to the carb, and 2) to the engine=99s mechanical
fuel pump and to the carb.
That way, if the mechanical pump quits, the electrical pump doesn=99
t have to try to push fuel though the mechanical one to get to the carb.
And, the mechanical pump doesn=99t have to pull fuel through the
electric fuel pump if the electric fuel pump is off or it quits.
Which way should this be set up, and and if you think it=99s the
way shown in the Europa builder=99s manual, why?
Jeff Williams
Builder A157
> On Apr 22, 2021, at 10:19 PM, Griffo <scangriffin@bigpond.com.au>
wrote:
>
<scangriffin@bigpond.com.au>
>
> Hi Dave,
>
> Hi,
>
> It=C3=A2=C2=C2=99s good that you are taking precautions to avoid
having the electric (boost/back up) pump mask/hide a failed mechanical
fuel pump.
> However, I would question the merit of leaving your electric pump on
at all times, as I would expect a pump, so operated, to become a service
item replaced at ?? hours of operation (as the mechanical pump has a
recommended service life).
> I only use my electric pump =C3=A2=C2=C2=93 prior to engine start
(off for start) to check fuel pressure/availability. On again, for
take-off. Off when safe height above terrain achieved. On again, when
downwind for landing.
> Your engine will run perfectly without the need for the electric pump,
which should only be used when you have a mechanical fuel pump failure,
at critical times, when fuel starvation is not a good option.
>
> --------
> 46
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=501476#501476
>
>
>
>
>
>
>
>
>
|