View source for Douglas DC-4E

{{Short description|US airliner prototype with 4 piston engines, 1938}}
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{{Infobox aircraft
 |name= DC-4E
 |image= File:Douglas DC-4E.jpg
 |caption= The Douglas DC-4E in flight
 |type= Experimental airliner
 |manufacturer= [[Douglas Aircraft Company]]
 |designer=
 |first_flight= June 7, 1938<ref name="FrancMcd2">Francillon 1988, p. 267.</ref>
 |introduction=
 |retired=
 |status=
 |primary_user= [[United Airlines]]<ref>Francillon 1988, pp. 266, 268.</ref>
 |more_users= [[Imperial Japanese Airways]]
 |produced=
 |number_built= 1<ref name="FrancMcd1">Francillon 1988, p. 268.</ref>
 |unit cost=
 |variants= 
 |developed_into= [[Nakajima G5N]]
}}

The '''Douglas DC-4E''' was an American experimental airliner that was developed before [[World War II]]. The DC-4E never entered production due to being superseded by an entirely new design, the [[Douglas DC-4]]/[[Douglas C-54 Skymaster|C-54]], which proved very successful.

Many of the aircraft's innovative design features found their way into the [[Nakajima G5N]] bomber after the single DC-4E prototype was sold to a Japanese airline and clandestinely dismantled for study by [[Nakajima Aircraft Company|Nakajima]] at the behest of the [[Imperial Japanese Navy]].<ref name="FrancMcd1"/>

==Design and development==
The design originated in 1935 from a requirement by [[United Air Lines]].<ref>Pearcy 1995, p. 17.</ref> The goal was to develop a much larger and more sophisticated replacement for the [[Douglas DC-3|DC-3]] before the first DC-3 had even flown.<ref>Yenne 1985, p. 122.</ref>

Such was the initial interest from other airlines, that [[American Airlines]], [[Eastern Air Lines]], [[Pan American World Airways|Pan American Airways]] and [[Trans World Airlines|Transcontinental and Western Air (TWA)]]{{#tag:ref|Transcontinental and Western Air renamed itself to Trans World Airlines after World War II.|group=N}} joined United, providing $100,000 each toward the cost of developing the new aircraft. As cost and complexity rose, Pan American and TWA withdrew their funds in favor of the [[Boeing 307 Stratoliner]], which was anticipated to be less costly.<ref name="FrancMcd2"/>

[[File:Douglas DC-4E Oakland.jpg|thumb|The giant new DC-4E at the United Air Lines base at Oakland Airport]]
[[File:DC-4nxNoseCloseup (4411721523).jpg|thumb|Close up of the nose]]

With a planned day capacity of 42 passengers (13 rows of two or more seats and a central aisle) or 30 as a sleeper transport (like the DST), the DC-4 (as it was then known) would seat twice as many people as the DC-3 and would be the first large aircraft with a nosewheel. Other innovations included auxiliary power units, power-boosted flight controls, alternating current electrical system and air conditioning. [[Cabin pressurization]] was also planned for production aircraft. The novel tail with three low [[vertical stabilizer]]s enabled use of existing hangars and provided sufficient vertical fin area to allow the aircraft to take off with only two engines on one side operating. The wing planform was similar to the DC-3, with a swept leading edge and almost straight trailing edge. The four {{convert|1450|hp|kW|abbr=on}} [[Pratt & Whitney R-2180-A Twin Hornet]] 14-cylinder [[radial engine|radials]] were all mounted with noticeable toe-out, particularly the outer pair.<ref>Francillon 1988, pp. 266–268.</ref>

==Operational history==
The prototype (''NX18100'', s/n 1601) first flew, without incident, on June 7, 1938 from [[Santa Monica Airport|Clover Field]] in [[Santa Monica, California]], piloted by [[Carl Cover]]. Testing issues, however, delayed the Approved Type Certificate until May 5, 1939. It was used by United Air Lines for in-service evaluation during 1939. On June 9, 1939, when the DC-4 was in Dayton, Ohio, along with Carl Cover, Orville Wright was a passenger on a flight over the city.  Although the aircraft was relatively trouble-free, the complex systems proved to be expensive to maintain and performance was below expectations, especially with an increase in seating to 52 and gross weight to {{convert|65000|lb|kg|0|abbr=on|adj=on}}.<ref name="FrancMcd2"/>

The design was abandoned in favor of a marginally smaller, less-complex four-engined design, with a single vertical fin and 21 ft (6.4 m) shorter wingspan. This newer design was also designated [[Douglas DC-4|DC-4]], leading the earlier design to be redesignated DC-4E (E for "experimental"). In late 1939, the DC-4E was sold to [[Imperial Japanese Airways]], which was buying American aircraft for evaluation and technology transfer during this period. At the behest of the [[Imperial Japanese Navy]], the DC-4E was transferred to the [[Nakajima Aircraft Company]] and [[reverse-engineered]], becoming the basis for the unsuccessful [[Nakajima G5N|G5N]] bomber.<ref name="FrancMcd1"/> To conceal its fate, the Japanese press reported shortly after its purchase that the DC-4E had crashed in [[Tokyo Bay]].<ref name="Airpower">Westell 1999. pp. 18, 49–50.</ref>

==Operators==
;{{JPN}}
* [[Imperial Japanese Airways]]
;{{USA}}
* [[United Airlines]]

==Specifications (Douglas DC-4E)==
{{Aircraft specs
|ref=''McDonnell Douglas Aircraft since 1920, Vol. 1''<ref name="FrancMcd1"/><!-- reference -->
|prime units?=imp<!-- imp or kts first for US aircraft, and UK aircraft pre-metrification, 
met(ric) first for all others. You MUST choose a format, or no specifications will show -->
<!--
        General characteristics
-->
|crew=3 (pilot, co-pilot, flight engineer)
|capacity=42 passengers
|length m=29.74
|span m=42.14
|height m=7.48
|wing area sqm=200.207
|empty weight lb=42,564
|gross weight lb=61,500
|max takeoff weight lb=66,500
|fuel capacity=
|lift kg=<!-- lighter-than-air -->
|lift lb=<!-- lighter-than-air -->
|lift note=
|more general=
<!--
        Powerplant
-->
|eng1 number=4
|eng1 name=[[Pratt & Whitney R-2180-A Twin Hornet|Pratt & Whitney R-2180-S1A1-G Twin Hornet]]
|eng1 type=14-cyl. two-row air-cooled radial piston engines
|eng1 hp=1,450<!-- prop engines -->

|prop blade number=3<!-- propeller aircraft -->
|prop name=metal variable-pitch propellers
<!--
        Performance
-->
|max speed kmh=394
|max speed note=at {{convert|7,000|ft|m|abbr=on}}
|cruise speed kmh=322
|range miles=2,200
|ceiling ft=22,900
|climb rate ftmin=1,175
|wing loading kg/m2=
|wing loading lb/sqft=28.5
|power/mass=0.0943 hp/lb (4.8kW/kg)
}}

==See also==
{{aircontent
|related=
* [[Douglas DC-4]]
* [[Nakajima G5N]]
|similar aircraft=
* [[Boeing 307 Stratoliner]]
|lists=
* [[List of civil aircraft]]
|see also=
}}

==References==
===Notes===
{{Reflist|group=N}}

===Citations===
{{reflist}}

===Bibliography===
* Francillon, René J. ''McDonnell Douglas Aircraft since 1920, Volume 1.'' London: Putnam & Company Ltd., Second revised edition, 1988, 1979. {{ISBN|0-85177-827-5}}
*{{cite journal |last1=Griffith |first1=Alan |title=Ploughshares into Swords: The Douglas DC-4/4E Bomber Projects |journal=The Aviation Historian |date=2019 |issue=28 |pages=20–31 |issn=2051-1930}}
* Pearcy, Arthur. ''Douglas Propliners: DC-1 – DC-7.'' Shrewsbury, UK: Airlife Publishing, 1995. {{ISBN|1-85310-261-X}}.
* Westell, Freeman. "Big Iron, big engines & bigger headaches: Building the first experimental strategic bombers." ''Airpower'', Volume 29, No. 6, November 1999.
* Yenne, Bill. ''McDonnell Douglas: A Tale of Two Giants.'' Greenwich, Connecticut: Bison Books, 1985. {{ISBN|0-517-44287-6}}.

==Further reading==
{{refbegin}}
* Grey, C.G. and Leonard Bridgman. ''Jane's all the World's Aircraft 1938.'' Newton Abbott, UK: David & Charles, Reprint 1972, First edition 1938. {{ISBN|0-7153-5734-4}}.
{{refend}}

==External links==
{{Commons category}}
* [https://books.google.com/books?id=jJGCcmbvL5MC&dq=DC-4+japan&pg=PA52 Photo of DC-4E being craned onto a ship for Japan from ''Flying'' magazine, December 1939]

{{Douglas airliners}}
{{Douglas DC-4 family}}
{{Japanese Navy short aircraft designations}}

{{DEFAULTSORT:Douglas DC-4e}}
[[Category:Cancelled aircraft projects]]
[[Category:Douglas aircraft|DC-04E]]
[[Category:1930s United States airliners]]
[[Category:Low-wing aircraft]]
[[Category:Four-engined tractor aircraft]]
[[Category:Aircraft first flown in 1938]]
[[Category:Four-engined piston aircraft]]
[[Category:Triple-tail aircraft]]
[[Category:Aircraft with retractable tricycle landing gear]]