|
|
Posted for MikeEasley@aol.com:
Pat,
The fuel system is one thing I spent a lot of time thinking about on my ES.
The new kits have 1/2" lines and there are a lot of IVs out there flying
with 3/8". In discussions with Mark Mankhe and Tim Ong a few issues came
up:
1: Mount the electric fuel pump as low as possible. On the ES, guys are
putting it on the floor at the bottom of the firewall in the center, right
ahead
of the fuel selector. I'm guessing you don't have the option with the
retractable gear.
2: The 90 degree AN fittings in the system are restrictive. Tim Ong even
quoted me a percentage, it seemed pretty high. The original design has two
90s before you even get inside the fuselage.
3: Bending the 3/8" tubing on a tight radius can cut the cross section by
50%.
I ended up coming straight out of the tanks with 1/2" Aeroquip, snaking it
up to the fuel selector. I used the large radius, mandrel bend 90s at the
fuel selector. Forward from the fuel selector to the pump, from the pump to
another large radius, mandrel bend 90 going through the firewall to the
gascolator. No bends, no 90s. I would bet my fuel system can move fuel
significantly better than a factory design 1/2" system, not to mention a
factory design
3/8" system. All that for a IO-550 with much lower fuel flows than the
TSIOs
can get at full power.
I know that my design can't be duplicated on a IV. You have pressurization
issues, but the principles are the same. I have since added grommets where
the lines go through the fuselage and bulkheads. It's not the hoses you
need
to be worried about, it's the bulkheads. The wire braid is very tough and
very abrasive. The feed hoses lay flat on the floor, and the return lines
are
slightly above the feed lines.
I was able to run the fuel lines across the floor diagonally when I
installed the wings. With the wings inserted part way, with about a 12"
gap between
the wing and the fuselage, the lines will reach the wing fittings. It was a
simple task to tighten the lines before fully inserting the wings.
I know my system is heavier than the aluminum tubing, but the fuel system is
an area where I was willing to add a couple pounds to gain reliability.
I have attached a few photos.
Mike Easley
Colorado Springs
Flying my ES
|
|