Folks,
I have a question. When I climb out in the Coupe, 415C, at 70 MPH , I notice
the fuel stick in the header tank guage seems to get lower than normal. But
shortly after I level off, the fuel inidicator goes back to full normal
showing. We just installed a new cap and float. I was wondering if with full
power and at this climb angle the fuel pump was not able to pump fuel into the
header fast enough. We have had no problems with the bird in any other area.
First time we noticed this we got concerned and flew around the airport before
heading off on a flight.
Is this normal ? Next time I will try a climb speed of 75 to see what that
does.
Thanks,
Jim
N3439H
KFDK
----- Original Message -----
From: William R. Bayne
To: ercoupe list
Sent: Friday, March 26, 2010 1:04 PM
Subject: [ercoupe-tech] Re: Fuel starvation:
I agree with Wayne that any coupe whose fuel system has the gascolator, or
fuel filter bowl (see Parts Catalog, p. 26, Item 54), mounted low on the
forward face of the firewall is subject to unanticipated fuel flow interruption
in the manner he describes. Some Forneys and coupes (not Alons) have been
retrofitted with this firewall-mounted gascolator by well-intentioned but
uninformed owners or mechanics.
I agree that this would seem the most likely cause of the recent crash in
Portugal.
Wayne's solution should be in the preflight checklist of any and all such
airframes.
Regards,
WRB
--
On Mar 26, 2010, at 07:49, Wayne Woollard wrote:
Ed:
I have advocated for many years that there is a serious problem with tha
architecture of the Alon fuel line routing.
The problem shows up if the fuel line is shut off at the base of the header
tank, and work is done on the remaining fuel system, or if the header tank is
drained for any reason or if all the fuel is consumed and it is refilled.
A basic fact of hollow lines is the fuel weight is enough to create a small
amount of fuel pressure at the carburetor, but this is not enough weight to
allow an air "bubble" to pass. A bubble of air in the fuel line will only
allow a limited amount of fuel to pass by, and will act as a partial
restriction, although THE LINE IS NOT RESTRICTED!!
This simple fact along with the fuel line routing to the Alon Gascolator
setup and beyond are the cause of many frustrating takeoff incidents, wherein
the equipment failure cannot be duplicated.
If you push down the tail of an Alon to duplicate the "Takeoff" angle of
attack and you have recently refilled your fuel system, an air bubble can occur
between the output of the header tank and the input to the carburetor. This
"Can" be duplicated by draining the header tank, and the loop in the fuel line
at the carburetor input, then refilling the fuel tank and powering up the
airplane, go through all the check lists, and taking off on a 3 mile long
runway, such as Castle, and see for youself. Halfway down the runway at an
altitude of 200 feet the engine will quit from fuel starvation! Plenty of room
remaining to land, but not so at a "Normal" airport.
Solution: Bleed the air from the fuel line connection to the carburetor by
disconnecting it and holding it to a position below the lowest point in the
fuel system till the fuel runs smoothly without air, and reconnect. following
all the safety procedures of course.
D. Wayne Woollard CPBE
o--iii---(
