Ercoupe Tech@Ercoupe.groups.io

This group is a forum for Ercoupe, Forney Aircoupe, Air Products Aircoupe, Alon Aircoupe, Mooney A-2A and M-10 Cadet aircraft owners, operators and enthusiasts.  New members are temporarily moderated to block spam.

Posting on this forum must relate to technical and/or historical information about airframes produced under Aircraft Specification No. 718 and Type Certificate Data Sheet No. 787, including propellers, engines, and associated modifications (including 337s, STCs, etc.) and techniques appropriate to the safe operation and maintenance of these unique and extraordinary aircraft. 

Most individuals belonging to this forum have no professional technical authority or certification.  Posts here even by the few that do are intended as an informal starting point for your own personal research.  Each subscriber is expected to personally verify any and all information posted here with standard aviation industry sources such as (but not limited to) aircraft maintenance manuals, flying instruction books and, above all, FAA regulations before, and to base any action taken or not taken on some officially published authoritative source!

The Ercoupe, et al share a proud lineage and civilian history.  The Engineering and Research Corporation (ERCO) was founded by Henry Berliner in Washington, D.C. in 1930 to design and manufacture aircraft and propeller production machinery.  In October of 1936, NACA Engineer Fred Weick joined ERCO; and on October 1, 1937, the experimental  ERCO Model 310 prototype flew for the first time.

Because no suitable engine was commercially available at that time, ERCO hired engine designer Howard Morehouse to design one.  In its final 1939 configuration, the Model 310 was powered by the result, an elegant inverted inline four certified as the ERCO IL-116 producing 65 hp; and had the "signature" twin fin/rudders of the future Ercoupe. 

The prototype Ercoupe, Serial No. 1 (now in the Smithsonian), was a foot longer than the Model 310.  This  was certified for production in January of 1940 as the ERCO Model 415 under CAA Aircraft Specification No. 718 .  Almost immediately, Continental Motors announced they would seek certification of their own Morehouse-designed 65 hp engine, an opposed four designated the A-65. 

The quoted price of the A-65 was about half what it cost ERCO to produce their IL-116.  Accordingly, Ercoupe Serial No. 1 was quickly modified to accept the new Continental engine; with CAA certification immediately requested for the new configuration.  The Ercoupe Model 415-C was added to Aircraft Specification No. 718 on March 1st, 1940.  Allowable gross weight was progressively increased by the CAA to 1260 lbs.

With 900 orders "on the books", 112 prewar examples were completed before wartime priorities on aluminum made further production impossible. The great majority of 415-C Ercoupes were produced between the fall of 1945 and the end of September,1946.  By that time, dealer demand had been satisfied, new orders had stopped coming in, and ERCO Field was filling up with unsold planes and production was stopped.

ERCO had argued since late 1945 that the existing 415-C airframe should be allowed the 1400 lb. gross permitted under the then-new "normal" category.  But the same new CAA rules creating the new "normal" category also created and imposed draconian flight testing regulations applicable ONLY to aircraft "Characteristically Incapable of Spinning" that no other aircraft design had to or could have satisfied. 

The CAA demanded ERCO apply for an entirely new Aircraft Type Certificate, No.787 to get approval for 1 1400 lb. gross for what became their Model 415-D.  These flight tested each airframe for acceptance at 1400 lbs. gross weight rigged with 13º "up elevator" (a more rearward CG, and excess rudder deflection, then limiting production examples to 9º maximum "up elevator" and other control movements identical to the 415-C model.  ERCO was not satisfied with the performance of the two Model 415-Ds thus approved in late March and early April of 1947, and produced no more.

The production line had already been changed over to produce the Model 415-D, so ERCO thensought and was granted CAA certification of the Model 415-CD.  This was merely the 415-D airframe as produced under Aircraft Specification 718, rigged for the original 13º of "up elevator" and with gross weight limited to 1260 lbs.  The first 415-CD was manufactured in late March of 1947 and the last in late June.  In the interim Henry Berliner had decided that ERCO would get out of the light plane business.  

All rights of design, assembly and distribution of Ercoupes (and related parts and service) were sold to Sanders Aviation, Inc.  Sanders then designed and obtained CAA certification for the later 415-E and G models.  Subsequent production variants of the Coupe were manufactured by Forney as F-1 and F-1A Aircoupes, Alon as A-2 and A-2A Aircoupes and Mooney as A-2A and M10 Cadets (ending in 1970); all under Type Certificate Data Sheet 787.  Of a fleet total of perhaps 5,508 produced, over a third (some 2000 or so) have remained on active registration here in the U.S. over some four decades.  Hundreds more remain active today in Canada, South America, and Europe.

Ercoupe in flight:  https://www.youtube.com/watch?v=P-RXph2MG64

A bit of military history...the Army Air Corps purchased three 415-C Ercoupes, two PQ-13s (Man-carrying Aerial Target) and one YO-55 (Observation type under official evaluation).  Due to poor research more than a few reputable aviation magazines have led many to believe that the paint scheme in the picture above is of the YO-55. Not so.  All three of the "military" Ercoupes were delivered in the standard bare metal finish with civilian N Number registrations and Serial Numbers.  In the case of the YO-55, this was Serial No. 39, NC28944, manufactured 02/03/1941.  The official AAC photograph of this aircraft taken 04/24/1941 at Post Field, Ft. Sill, OK, confirms the latter information.  Our picture is of a genuine prewar Ercoupe 415-C Serial No. 110, NC37143, manufactured 08/13/1941.  This airframe was purchased 08/19/1941 by the Air Corps and delivered to Wright Field, Dayton, Ohio.  The Army designated it as a PQ-13 , Serial No. 41-39099.  Thiis airframe is the sole known survivor of three original military Ercoupes. 

A previous owner chose to paint Serial No. 110 as the much more famous PQ-13, Serial No. 11, manufactured 12/04/1940. That airframe was sold to the "War Dept., Air Corps. Material Division on 01/04/1941 and assigned Air Corps Serial No. 41-25196.  Delivery as civilian 415-C NC28655 was to Wright Field, Dayton, Ohio.  This was the aircraft  loaned from Wright Field to the Jet Propulsion Laboratory (JPL-GALCIT) project for testing their JATO (Jet-assisted Take Off) concept. 

At the time, JPL requested a "YO-55", likely because (1) the all-metal airframe of the Ercoupe would be much better suited to such testing than the wood and fabric designs of its contemporaries, and (2) few at the time were aware of the Air Corp's identical PQ-13s (being a bit of a "hush-hush" endeavor).  More than a few official reports used the "YO-55" designation for the loaned airframe, NC28655, which was officially designated as a PQ-13 throughout its active military service.  There is official correspondence from 1941 confirming this misnomer.

The rudders of Ercoupe Serial No. 11 were increased in area and rigged for additional effectiveness before the JATO testing.  This, per Army practice, made this airframe a "XPQ-13" (a modified PQ-13).  It was flown from Wright Field to Muroc Army Air Field (later Edwards Air Force Base) in the high desert of Southern California..  Flight tests commenced August 12th and concluded August 21st of 1941 proved the feasibility of utilizing expendable rockets to boost warplanes into the sky (with greater ordinance loads or standard loads from shorter runways) and earned related projects increased government funding and further development. 

In 1942 the CAA complained about the military operating this PQ-13 with the civilian registration NC28655.  That registration was cancelled and the aircraft was repainted as generally shown above.  The black and white "official" "PQ-13" photograph was taken at Wright Field on April 8, 1942.  The increased areaof the rudders is distinctively apparent.

We intend that the "culture" on Tech be positive.  Negative comments about any person are unacceptable.  We reserve the right to moderate all messages to stay on-topic and prevent flame-wars.  Please address facts and ideas.  Try to be clear whether you share facts, logical speculation or mere opinion.  Just present what you have to offer on a given subject and, if you can, provide verifiable reference to your source(s).     

Membership in the Ercoupe Owners Club is encouraged but optional.  Web site:

      https://www.ercoupe.org/

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