Hi Ron,
Maybe I'm prejudiced, but I believe the Ercoupe has one of, if not THE,
safest fuel system designs in aviation ever. Unless one flies at full
tilt boogie into a ridge or tree at speed, or manages to "arrive" with
such vertical velocity that the control column ruptures the fuselage
tank, or flies with a known fuselage tank leak, fires in the cockpit
are extremely rare and most likely electrical in origin. An engine
compartment fire has little to burn if the two valves in the cockpit
are quickly shut off.
The Ercoupe does not have a "fuel pump" in the sense that most other
planes do. Our pump does not supply the engine with fuel. It merely
pumps fuel from the wing tanks, so long as fuel is available there and
the pump functions properly, into the fuselage tank. Failure of either
a mechanical or electrical TRANSFER PUMP in our birds is likely more of
an emergency in Canada or Alaska than in the continental U.S.
Transfer pump failure does not stop our engine. It just calls to our
attention the possibility that the engine will eventually stop if we do
nothing.
Our "bobber" gauges only float (indicate) from approximately half full
to full (they are "thumping bottom afterward), and the wire can be
color marked to indicate each gallon consumed within that range. I
like the Skyport "Rain Pruf" gauge with the external tube and a ring
marked around the "normal" position of the top of the "bobber"
indicator. With either, it is obvious pretty quick (to a pilot who
regularly checks his/her fuselage tank fuel indicator) once fuel used
from the fuselage tank is not being replaced.
Ercoupes through Serial No. 2622 have five gallon fuselage tanks, while
those subsequent have six gallon capacity with which to reach an
airport and land safely. If an Ercoupe pilot leans the engine and cuts
forward speed in most instances the fuel burn can be brought to or
below 4 gpm. Depending on the pilot's vigilance there should be from
an hour to an hour and a half or so flight time available at eighty
plus mph.
There's not many places today that an airport suitable for landing an
Ercoupe is more than eighty miles away. In those places I might seek
to land on a road and would carry a container with which to drain wing
tank fuel for manual transfer into the nose tank so as to continue
back. Even on the 290 nm leg from Freeport to Long Island in the
Bahamas one could divert to Great Abaco Island or Cat Island...and then
there are beaches.
Today's GPS navigation allows almost instantaneous and appropriate
response to the inconvenience of pump failure. If proper situational
awareness is maintained (you're not already lost, and you're checking
off progress along course with landmarks), even those with only
sectional charts and plotting ruler only have an emergency if they
panic.
Accordingly, I don't think either the mechanical pump or the electrical
pump have a "safety" advantage. As to the legality, a few Ercoupes
have electrical pumps. If there is a 337 appropriately submitted,
accepted and applicable to a particular airframe it's probably "legal".
Regards,
William R. Bayne
.___|-(o)-|____.
(Copyright 2010)
--
On Feb 2, 2010, at 22:36, Ronald Hynes wrote:
Bill, I have quite often wondered if it is safer and of course Legal
to do away with the engine driven fuel pump and use an electric fuel
pump instead. Any thoughts on this ? Alons style.
Ron Hynes, Alberta, Canada
