Hi Donald,
If you refer to the back of the Service Manual (about two thirds down
the listing of "Ercoupe Modifications"), you will see that production
wing tanks were changed (from terneplate) to aluminum with serial
number 2623. Your bird originally had all terneplate tanks.
Prewar Ercoupes are listed in brochures as having fourteen gallon fuel
capacity. That was with a five gallon nose tank and one nine gallon
wing tank. Early postwar brochures show a fuel capacity of 23 gallons
with the same five gallon ternplate fuselage tank and two nine gallon
wing tanks. Later on this increased to 24 gallons when the 6 gallon
aluminum nose tank replaced the five gallon ones (terneplate thru
serials 2468 and stainless from 2469 to 2623).
The Parts Manual suggests that 415-48083-L/R tanks were stainless
replacements for original terneplate wing tanks. These stainless
replacement tanks were apparently designed and fabricated to fit
Ercoupes with serials up through 812 (with the main landing gear
mounted on the forward face of the main spar) as well as serials 813
through 2623 (with the gear mounting to the rear of the rear face of
the spar).
As of the issuance (on or after 9/26/46, per Fig. # 1) of Service
Memorandum No. 31, production was passing serial no. 3672. Paragraphs
3 and 4 make it clear that, as of this time, terneplate (or replacement
stainless wing tanks) or aluminum wing tanks installed in a production
(non-experimental) Ercoupe had a nominal capacity of nine gallons.
As of the issuance of Service Memorandum No. 39, ERCO was receiving
requests to replace terneplate wing tanks with the aluminum tanks, and
item 8 confirms that each had the same (9 gal.) capacity. As Richard
has pointed out, the aluminum substitution is seven pounds less. In
order to install "current production" tanks (parts no. 415-48187L & R)
a fuselage cutout was necessary (see Sketch A).
As of the issuance of Service Memorandum No. 43 (on or after 10/19/46
per drawings 48178-80), aluminum tanks 415-48187L & R were installed
"serials 3468 & subsequent". Sketches suggest that aluminum wing tanks
48128L & R were originally fitted to serials 2623 thru 3467, and these
were logically of nine gallon capacity.
We can see that ESM-49 came out subsequent to production of serial no.
4729 on 5/13/47, with ESM-50 following. This describes replacement of
wing terneplate tanks with a replacement aluminum tank "recently
approved" by the CAA. Identified as part numbers 415-48197L & R, ERCO
should have said much more about these tanks here.
Aircraft Specification No. 718 offers more information, p. 4, item No.
108. These are the elusive "eight gallon aluminum wing tanks" that
hold 7.7 gal. (ea.). They had less capacity so that installation on
serials 813 through 2623 (with the gear mounting to the rear of the
rear face of the spar) was possible without cutting the fuselage skin
(per ESM-39). System capacity is 20.4 gal. with these and a five
gallon fuselage tank.
Becoming available this "late in the game", it should be obvious that
aluminum replacement tanks 415-48197L & R were NEVER installed during
production on ANY Ercoupe.
I am aware of NO "eight gallon" stainless tanks being produced or
installed at any time.
Regards,
William R. Bayne
.____|-(o)-|____.
(Copyright 2010)
--
On Feb 21, 2010, at 17:48, John Cooper wrote:
On 2/21/2010 6:19 PM, Donald wrote:
I understand that my Coupe may have "Ternplate" (whatever the heck
that is) or aluminum or stainless wing tanks. Is there an easy way
to tell just what kind of tanks I have?
"Ternplate" (a bastardization of terneplate) is basically steel coated
with a combination of lead and tin (solder). It is magnetic. Stainless
tanks were replacements for the terneplate tanks. All stainless wing
tanks are 8 gallons. and not magnetic. The aluminum tanks are not
magnetic and are 9 gallons.
--
John
Skyport East
www.skyportservices.net
