It seems that decreasing the pumping volume in the lines up to the intake of
the pump would speed the fuel through a bit quicker, especially in partially
blocked filter situations (So I wonder if 'tortuous plumbing' could mean:
bigger fuel lines). I am considering a slightly smaller inlet area to the
pumps, than on the output of the pumps. For example: 5/16" aluminum tubing
on the input to the pump, and 3/8" on the output, though haven't verified
the flow rate for the 5/16" yet (at pressure, -intend using 914).
Originally, I was going to mount the filters under the seat (before the
pumps, to protect them), and the gascolator well 'behind' the pumps in a
typical area, up front by the engine, but have seen a few engine outs due to
fuel starvation of just one filter. One could always switch to the reserve
tank, but in the 'heat of the battle' of takeoff, that could be considered
difficult or dangerous. Now the filters intended position will be moved to
just before each pump (in the series//parallel mode, next to the Andair
check valves), and a water drain/check mounted in the seat well, in place of
where the filter was to originally go.
Rowland, I am currently planning to go the route you were surmising, and
will put 3/8" aluminum in the long runs through the cockpit module (pump to
engine, engine return back to tank). This will obviate the need to replace
the rubber there. The lines are being installed now, before the module gets
cemented in place. I have the Tri-gear, and am running the fuel line roughly
where the manual calls it out, a bit below the top of the center console.
Hopefully, it will be adequate (fingers crossed).
Looking at all the fittings needed (and the lack of), hooking it all
together seems a bit overwhelming. It is hard to find 5/16" of anything
articulate, and many things on the Europa use 5/16". I think the pump needs
a 5/16 to 12mm adapter (from memory, so it may be wrong). The Andair check
valves could use 3/8 or 1/4" fittings, and so on. Don't know what the return
feedline needs from the regulator output. Many options, and also many
limited options. If anyone has produced a table, or schematic, or drawing of
all the different fittings sizes, and where they were used, it would be oh
so most helpful to me, as I have already pulled out some of my hair :). Even
if it isn't the exact way I will be implementing, it would still give a good
idea of what fitting is needed where...
Regards,
Greg Fuchs
A050 XS TRI 914
-----Original Message-----
Depends on the type of pump.
A roller-cell pump (914 etc) is very intolerant of dirt (it scores the
traces in the pump). The shuttle type pump (eg Facet) is far more tolerant.
Both types of pump are much better at pushing than pulling; so any partial
blockage of a filter on the suction side will test the ability of the pump
to suck (typically a maximum suction head of 0.6m is quoted for roller cell
pumps; much of this allowance can be used up with high flow rates and the
tortuous plumbing frequently seen). This is asking for trouble, particularly
if Mogas is being used.
Duncan McF.
----- Original Message -----
From: "Robert C Harrison" <ptag.dev@tiscali.co.uk>
>
> <ptag.dev@tiscali.co.uk>
> (Of course in this context "ahead" may be the same). The last thing you
> need in the pump is unfiltered fuel.
> Regards
> Bob H G-PTAG
> -----Original Message-----
> Subject: Re: Europa-List: fuel pump etc
>
>>This is what I did.....
>
> Mike - thanks for the nice pictures. The layout looks neat ....
> But shouldn't the gascolator be ahead of the fuel pump in the sequence?
>
> regards
>
> Rowland
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