Actually, it's 4423 (the last 415-C). The FAA-approved Flight Manual
for the E and G Models states, on p. 8
(with reference to wing tank caps), "do not use caps with vents in this
model Ercoupe. The fuel schematic
on p. 7 is functionally identical to that shown in the FAA-approved
Flight Manual for the D Model on p. 7.
415-D and 415-CD airframes are identical in every respect excepting
only the allowed elevator movement
and allowable gross weight. Accordingly, the fuel system schematic for
the 415-D model is also applicable
to the later 415-CD Model; although there is NO FAA-approved Flight
Manual for the model 415-CD.
Because of widespread replacement of the terneplate tanks originally
fitted to Ercoupes through serial
number 2622 with ones of differing capacities and configuration
constructed of either stainless steel or
aluminum, and Erco's decision not to stock replacement lines for any
but the latest production configuration
of the various production schematics (see Ercoupe Parts Manual and
Ercoupe Service Memorandums 39
and 43), and factory "updates" of unsold 415-C airframes to the later
415-CD model, there are almost as
many Ercoupe plumbing variations today in the field as there are
Ercoupes.
Serial numbers are NOT a reliable way to determine whether a given
Ercoupe should have vented or
unvented wing caps. There are serial number glitches throughout the
Parts Manual and Bulletins and
Memoranda. We all have abstract doubts, but few of these can survive
the determined application of
diligent and competent scrutiny. You need to properly understand how
YOUR fuel system functions.
If your Ercoupe has a separate overflow line feeding into each wing
tank (i.e. it conforms to
the fuel schematic installed in the 415-D, CD, E and G models and each
wing tank vents to the header tank),
it "vents" to the header tank via the overflow lines and SHOULD NOT
have vented wing tank caps.
With a good seal between each such tank and its unvented wing tank cap,
the problem of fuel "venting" out
of filled wing tanks when departing cross country is eliminated...an
advantage well worth installing the tee
and additional overflow to the other wing tank (in my humble opinion).
I want every ounce of fuel my wing
tanks will hold available for cross-country use, and do not view
regularly venting out (wasting) upwards of a
gallon (per leg) as acceptable (not that this is typical of vented wing
tanks, but also not exactly uncommon).
If unvented caps are installed on a plane that should not have them,
the "penalty for being wrong" is no
different than if a bug blocks the forward-facing vent of one of two
tanks fitted with vented caps. If the cap
blocked is on the tank with the overflow line, said tank continues to
vent to the header tank through it (i.e.
would not be affected). If it is on the other tank, erratic fuel
readings might result, and some of the fuel from
the unvented tank might be unusable. Such an in-flight occurrence
should NOT create an emergency
situation for any but the most obtuse pilot.
Best regards,
William R. Bayne
.____|-(ø)-|____.
(Copyright 2009)
--
On Apr 8, 2009, at 11:54, John Cooper wrote:
The cutoff for the vented caps on the wings is sn 4424. Reference the
Ercoupe parts catalog.
Due to the way things have been swapped around over the years, I’d be
absolutely certain the fuel system you have matches the configuration
from the factory before switching to unvented caps. The penalty for
being wrong is much more severe than if you put vented caps on a
system that doesn’t need them.
John Cooper
Skyport Services
www.skyportservices.net
