Hi Al,
The first "purpose" could be to successfully withstand a FAA "ramp
check"
if an inspector witnesses an owner fill the tanks and get into an
Ercoupe
with a passenger. "Legal" then is the difference between continuing
one's
departure and being "busted" and grounded for over gross operation.
The 1320# Gross STC does not physically change the load an Ercoupe
can carry safely. The conversion of a 415-C to a 415-D model actually
reduces safety in reducing elevator control available to the pilot and
raising
minimum landing speed. The second "purpose" is the addition of a
stainless
"firewall extension" panel to protect the fuselage tank, pilot and
passenger.
Ercoupe Serial No. 1 was originally manufactured and certificated as
the one
and only model 415 with the inverted inline Erco 65hp four cylinder
engine.
The Continental opposed-cylinder four was substituted as soon as it was
available because the cost to Erco was much less. The Continental's
shape
was simply incompatible with original model 415 cowling and firewall.
Fred Weick's cowling for the 415-C extended almost to the windscreen.
No
one at Erco or the CAA realized it now covered part of the original
fuselage
when the change was approved, and that the aluminum skin in this area of
the upper fuselage would be vulnerable to any engine compartment fire.
Erco had to remedy this before CAA approval was granted for its 415-D
model; but 4423 Ercoupes (over two-thirds of all made) had already been
manufactured with inadequate firewall protection. For new production,
Erco
detailed installation of the stainless panel without aluminum skin
underneath.
It thusly became common practice in field retrofits to remove the
original
aluminum skin in this area prior to installation of the stainless
panel. To
such extent as removal of the fuselage tank was necessary (in the days
before Cherry style rivets), few (if any) owners authorized such major
work
unless upgrading to the model D to be allowed the 1400 lb. gross weight.
Installation of the stainless panel certainly improved safety of
operation, and
is permissible to individual 415-C airframes without a model change.
If the
expense were less and approval easy. more owners would do this.
No qualified mechanic I have asked has come up with any credible reason
why the stainless panel could not be simply installed over the existing
aluminum skin with Cherry rivets (other than speculation that "the FAA
has
never specifically approved the modification to be done that way").
How about it, one of our A&P or IA persons? Anyone have such a 337 (or
the
necessary FAA "connection" to get a 337 or STC for such a simple
"safety of
flight" modification? The easier and less expensive it is, the more
will do it.
For the good of the fleet...
William R. Bayne
.____|-(o)-|____.
(Copyright 2009)
--
On Feb 14, 2009, at 17:24, Al Demarzo wrote:
And why would you want this? Does it beef up the structure so that
your Ercoupe can carry more weight? The only purpose I can this "mod"
has is that it makes the pilot in command feel good that he now can
legally carry more weight.
Just like the 1400 gross increase to a D model that everyone is
kicking themselves for obtaining, you can't purchase a safe flight.
Al, I Just Don't Get It, DeMarzo
