Douglas DC-4E

https://en.wikipedia.org/wiki/Douglas_DC-4E

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 The DC-4E never entered production due to being superseded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/C-54, which proved very successful.
Many DC-4E design features found their way into the Japanese Nakajima G5N
bomber.

The design originated in 1935 from a requirement by United Air Lines. The goal
was to develop a much larger and more sophisticated replacement for the DC-3
before the first DC-3 had even flown. There was enough interest from other
airlines that American Airlines, Eastern Air Lines, Pan American Airways and
Transcontinental and Western Air (TWA) 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, which was
anticipated to be less costly.

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 stabilizers 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 1,450 hp (1,080 kW) Pratt & Whitney R-2180-A Twin Hornet 14-cylinder
radials were all mounted with noticeable toe-out, particularly the outer pair.


Role
Experimental airliner

Manufacturer
Douglas Aircraft Company

First flight
June 7, 1938

Primary users
United Airlines
Imperial Japanese Airways

Number built
1

Developed into
Douglas DC-4
Nakajima G5N

The prototype (NX18100, s/n 1601) first flew, without incident, on June 7, 1938
from 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 65,000 lb (29,484 kg).

The design was abandoned in favor of a marginally smaller, less-complex
four-engined design, with a single vertical fin and 21 feet (6.4 meters) shorter
wingspan. This newer design was also designated 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; it was reverse-engineered
and became the basis for the unsuccessful Nakajima G5N bomber. The Japanese
press reported shortly after purchase that the aircraft had crashed in Tokyo
Bay, but it was being secretly studied by military and corporate interests at
Nakajima.

Specifications (Douglas DC-4E)

General characteristics
Crew: three
Capacity: 42 passengers
Length: 97 ft 7 in (29.74 m)
Wingspan: 138 ft 3 in (42.14 m)
Height: 24 ft 6 in (7.48 m)
Wing area: 2,155.01 sq ft (200.207 m2)
Empty weight: 42,564 lb (19,307 kg)
Gross weight: 61,500 lb (27,896 kg)
Max takeoff weight: 66,500 lb (30,164 kg)
Powerplant: 4 × Pratt & Whitney R-2180-S1A1-G Twin Hornet 14-cyl. two-row
air-cooled radial piston engines, 1,450 hp (1,080 kW) each
Propellers: 3-bladed metal variable-pitch propellers

Performance
Maximum speed: 245 mph (394 km/h, 213 kn) at 7,000 ft (2,134 m)
Cruise speed: 200 mph (322 km/h, 174 kn)
Range: 2,200 mi (3,500 km, 1,900 nmi)
Service ceiling: 22,900 ft (7,000 m)
Rate of climb: 1,175 ft/min (5.97 m/s)
Wing loading: 28.5 lb/sq ft (139 kg/m2)
Power/mass: 0.0943 hp/lb (4.8kW/kg)




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