Ron Swinden wrote:
>
>Dear Richard thank you for your comprehensive letter on problems with the
>Europa fuel system. Hopefully this is one that the American leg of the
>company will re-send to the factory for their attention. Fuel systems on
>aircraft never fail to amaze me with the troubles they come up with. Everyone
>does their best I am sure but still the problems arise. I'm not too sure
>about about the electronic solutions, they really ought not to be necessary
>but I hope your letter does produce a factory response, it certainly deserves
>it.Thanks for sharing your thoughts with us, I will take a copy of your
>letter to the National Committee meeting on Saturday and try and bend
>Francises ear with the subject. All the best Ron S No 33.
>PS been kicking ideas about with me mate Grenville and we have two
>suggestions to offer 1.turn the vent pipes thru 180 degrees ( curse him I've
>just glued the B thing in) and connect the two vent pipes togther with two
>tee pieces.
>2. fit a little pot (just below the vent pipe) with the two vents feedig into
>the top projecting a little way in. Halfway down the pot two more pipes
>sticking into the pot about 1/4" these to connect to the fuel tank vent and
>the guage vent. One more outlet from the bottom of the pot this pipe to be
>flush with the bottom it should be piped away through the bottom of the a/c
>its purpose in life being to dump fuel (collected when your plane with full
>tanks leans the wrong way), or rain out of the pot. Polite constructive
>coments /critisisms requested please especially constructive ones as I would
>love to achieve a safe working system without cutting the tank about or
>adding electronics or any extra equipment if at all pos.! Ron S No 33
Fiddling with the vent pipes cannot really solve the fundamental
problem which is the fact the sight gauge is teed off the main
line to the engine. It must not do this. Even a tee into the
balance pipe between the tanks will not do.
I agree our scheme is relatively complicated but we have been
building it in all along. The easiet retrofit I can think of is as
follows:
Remove one of the outlet plugs in the bottom of the tank and make up
a new one with two pipe fittings rather than one. Preferably one
of these outlets should extend an inch or two into the tank, both
could be still inside the gauze mesh. Run one to the sight gauge
and the other as before. Bubbles could not enter the main line
with this scheme unless you really were out of fuel.
As for the vents, I would still favour a scheme as described before,
in a loop eventually venting to the underneath of the fuselage
with some sort of arrangement such as tees to two pipes or possibly
a plastic filter to a larger pipe to prevent syphoning. This
would be simpler than what you suggest though it depends on there
being a high pressure area around the vent exit for the system to
perform as it does in normal conditions now. Your pot might not
correctly pressurise the tank if it drained to an area of negative
pressure.
Regards
-------------------------------------------------------
Richard Meredith-Hardy TEL + 44 (0)1462 834776
rmh@flymicro.win-uk.net FAX + 44 (0)1462 732668
CIS: 100071,2422
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