The Douglas Aircraft Company's
DC-4 conducted its maiden
flight on June 7, 1938. It was a hugely successful four-engined aircraft used for
civilian and military passenger and cargo transportation. Military versions of the
plane were designated
R5D. The DC−4 was designed to be
the airline industry's "dream" airplane - "a Grand Hotel with wings", capable of
cruise speeds of more than two hundred miles per hour and a range of 3,300 miles,
making it capable of non-stop coast-to-coast flight. Although the DC−4 was the brainchild
of United Airlines, a consortium of five companies - United, TWA, American, Eastern
and Pan American - financed the endeavor to ensure success would not be hampered
due to cost and competition concerns. The airplane's control systems were so complex
that a new crew member position called "flight engineer" was created to monitor
and tend to all the meters, dials, knobs, switches, and panel lights, while allowing
the pilots to worry mostly about flying. Although the DC−4 built on the overwhelming
success of its predecessor, the DC−3, such a large plane with twice as many engines,
tricycle landing gear, and many new creature comfort features required out-of-the
box thinking from the engineering team. The effort paid off big time, and earned
Douglas Aircraft Company kudos for a second paradigm-changing aircraft. I have always
wanted to build a control-line C−54, but I'm three years into a much simper
now, so its likelihood is growing less by the day.
First of the Giants - Triple Tail DC-4
Twenty-five Years Ago United Air Lines Proposed
a Dream Plane. Douglas Built It. They Called It the DC-4. Doug Ingells Tells How
the 50,000-lb Triple-Tailed Giant Changed Air Travel.
Early in 1936, William A. "Pat" Patterson, President of United Air Lines, called
a meeting of operations and traffic personnel. The "Mainline" - pioneer transcontinental
carrier - was in a jam. United's fleet of 10-passenger Boeing 247 transports was
outclassed by the newer, larger, faster DC-3's used by American Airlines and Transcontinental &
Western Air (TWA). Something had to be done about it.
As an interim measure Patterson had ordered, DC-3 airliners, too. He had spent
more than $1,000,000 to "soup-up" the Boeings. But Patterson knew that United must
hit the competition with a Sunday punch.
"What do we want in an airplane?" Patterson asked the group. The result was a
composite dream plane: a four-engined luxury transport capable of carrying 40 or
more passengers, performability that would enable it to leap across the continent
with only one stop, speeds better than three-miles-a-minute!
Patterson took the broad concept to Commander Jerome C. Hunsaker; aerodynamic
expert at Massachusetts Institute of Technology, for a basic airframe design, and
to the Pratt & Whitney engine people for powerplant potentialities. Before long,
he had detailed "specs" for the new sky giant. With these in his briefcase he made
the rounds of the various aircraft factories. Boeing was, too busy building big
flying boats. Consolidated Aircraft said the airline people didn't know how to design
airplanes. Sikorsky submitted a bid so low that Patterson's own directors ignored
But at Douglas Aircraft Company in Santa Monica it was a different story. When
Don Douglas - whose DC-3 was acknowledged as the best airplane ever built - heard
about the proposal and learned his former boss at MIT, Jerry Hunsaker, was in on
the project, the Scotsman expressed keen interest. Douglas called in Chief Engineer
Art Raymond and they began to put some ideas down on paper.
The next time Douglas, Raymond and Patterson met, there was only one question.
Raymond put it to Patterson - "Engineering such a plane will take a lot of time
and a lot of money ... are you just looking or buying?"
"We'll put up $300,000 for the engineering cost, if you'll foot the bill for
the rest," Patterson told Douglas.
Douglas remembered his experience with the DC-1. The initial $125,000 TWA put
up was just a starter. He had lost money until they were well in the production
stages with the DC-2's. Then, it was the foreign business and additional airline
orders that finally took the company off the hook.
Twenty-five years ago United Air Lines proposed a dream plane.
Douglas built it. they called it the DC−4. Doug Ingells tells how the 50,000th Triple-Tailed
Giant changed air travel.
"Front office" of the DC-4 presented a complexity of instruments
that awed most pilots back in 1938. This mock-up was photographed in the Douglas
shops in that year.
A new term was "Flight Engineer," this was his station. The triple-tailed
transport pioneered the "third man" in the cockpit. Today he is standard part of
every big airliner.
Tackling such a giant project as Patterson was proposing could wipe out all the
gains and put the Douglas Company's prestige position on the block. Unless ... ?
Could Patterson guarantee enough orders so the risk would be minimized?
Patterson had an answer for that one. Other airlines - TWA, American, Eastern
and Pan American - had heard about the super airliner. They wanted "in" and all
had agreed to split the engineering cost with United. The "Big Five" had signed
a pact that none would spend any money with any other company in the design and
development of a plane in this weight category until they had first evaluated the
Douglas design. If the big ship proved up to expectations orders would follow.
It was almost like money in the bank. Douglas accepted the challenge. The DC-4
The super transport - roughly three times the size of the DC-3 - came to life
behind huge canvas curtains that screened off a section of the Santa Monica plant.
The magnitude of the task was described in a Company press release: "More than
500,000 hours in engineering and design, another 100,000 hours of ground and laboratory
tests, eighteen months to build. Some 20,000 different pieces of metal framed to
different shapes, 1,300,000 rivets. Total, cost - $992,808 for labor and engineering,
$641,804 in materials and overhead."
During the building of the DC-4 the plant took on a new appearance. Douglas,
himself, walking through the shops one day and looking up at the maze of scaffolding
around the jigs and forms for the huge wing made the remark, "That looks like a
part of a ship's superstructure, not an airplane wing spar. It's hard to believe."
Another time Douglas confided to Raymond, "I knew we could design planes as big
as this and bigger; but I frankly didn't know how we would ever build them!"
The size of the DC-4 posed a new problem with every progressive step. Take the
engine controls system. Each of the two outboard engines was seventy feet from the
cockpit. Yet, somebody had to work out a means that would permit the same positive,
sensitive response possible when power controls were only a few feet away from the
engines as in the DC-3.
"We had to start from scratch," recalls Ivar Shogran, Douglas' Chief of Powerplants.
"It meant designing a whole new controls system. But finally, we whipped it with
a combination of push-pull rods and cables that ran through the internal structure
of the thick wing. It was rather ingenious ... and it worked."
Shogran points out that they also had to devise a new fuel feed system, too.
"Each engine had a 100-gallon tank of special take-off fuel and another 300-gallon
tank of cruise fuel. You could switch from one tank to another with the flip of
the wrist. It gave the pilot extra power for take-off, the critical moment of any
flight. Yet, once the ship was airborne and set for cruise speeds she was ready
to start an economy run."
The engine control system and the new fuel-feed technique brought about a major
innovation in big aircraft design - the Flight Engineer's Station.
According to Douglas the problem was this: "We felt from the very beginning that
an airplane of this size was just too much for one man to handle. It seemed we were
asking that a pilot or co-pilot have four hands. So we built duplicate engine and
hydraulic system controls and installed a second control board just behind the pilots'
station. It meant putting a third flight crew member up front, but it took a great
load off the pilots during critical flight moments."
Another problem concerned the controlling surfaces. The DC-4's ailerons, rudder,
elevators were bigger than the wings on training planes Douglas was still building.
Only a Superman could be expected to move these huge "planes" in the man-made hurricanes
whipped up by the powerful propellers.
Solution? Control "boosters" were designed and applied. The standard control
cables were replaced with small diameter hydraulic lines. Small electric motors,
driving pumps, used the principle of the hydraulic automobile brake to operate ailerons,
rudder and elevators. In short; the DC-4 introduced finger tip control and "power
The matter of flight control plagued the aerodynamicists. Especially in determining
of the shape and size of the rudder. Bailey "Doc" Oswald, Chief Aerodynamicist,
reminisces, "It got to a point where we had blown up the DC-3 rudder to almost five
times its normal size and still we had instability. The normal rudder configuration
simply was no good."
He adds, "Then somebody, I don't know who it was, suggested we try three smaller
rudders and vertical stabilizers instead of one. The result gave the ship remarkable
stability especially during two-engine operation. And this was a must requirement
... that the plane be able to fly on any two engines."
(Later, they whipped the rudder problem and production models emerged with single
rudder configuration. But there was a triple-tailed DC-4!)
She was a giant. "It looks like somebody put a magnifying glass on the DC-3 and
made it three or four times its normal size." This was the comment Don Douglas heard
from one of the newsmen invited to see the roll-out of the plane in the spring of
These dimensions justified the remark: Wing span, 138 ft., 3 inches; Fuselage,
97 ft., 7 inches; Wing Thickness, 4 ft., 6 inches; Propellers, 14 ft. dia.; Weight,
And she did look like an "overgrown DC-3." Even an official Douglas Company announcement
declared that the new all-metal sky leviathan's "design and construction follows
closely that of the DC-3."
At the same time Donald Douglas emphasized, "The DC-4 in no way replaces the
famous twenty-one passenger DC-3. Rather, it is an independent development anticipating
future needs for greater load capacity in trunkline operations for long distances.
It represents the Douglas Company's contribution to the science of aeronautics -
a new and significant milestone in aviation's progress."
The DC-4 was all of that and more. They called her "a Grand Hotel with wings!"
She could accommodate 42 guests by day and 30 by night. There was a Ladies' Lounge,
a Men's Dressing Room, a private compartment up front called the "Bridal Suite."
Comfortable seats arranged two abreast-twenty along each side - could be made up
into sleeping berths. Other features: air-conditioning, hot and cold water, electrically
operated kitchen or galley. There were also curling irons for the ladies, electric
shavers for the men and telephone service while the plane was in port or airborne
within radio contact range.
Virtually every improvement and innovation then available to the aircraft builder
was incorporated in the DC-4 - auto pilots, de-icers, controllable-pitch propellers,
a galaxy of instruments and navigational aids for the pilots. There were also features
which she pioneered.
The DC-4, for example, was the first craft of its size to incorporate the tricycle
landing gear. Instead of the familiar nose-up tail wheel and main landing gear (two
wheels) arrangement, the plane rested on two main wheels and a nose wheel. This
tricycle undercarriage meant that the big ship's fuselage was level when parked
on the ground, a boon to passengers.
More important, the tricycle gear greatly improved the plane's take-off and landing
characteristics. The airplane, in normal level flight attitude on the ground, presented
the control and lift surfaces to the airstream right from the beginning of its taxi
run - cutting out the need to "lift the tail high." In landing, the new arrangement
enabled pilots to literally "fly" the ship in, rather than let it settle with loss
of lift at the last minute. "Positive control right to touchdown," pilots said.
On the ground, they also claimed its taxiing capabilities far exceeded the maneuverability
of smaller planes because of the kiddi-car type undercarriage. You could turn the
giant on the proverbial dime.
Retracting the nose wheel and the big dual-wheels of the main gear was a major
mechanical problem. But the ship had "muscles" new to aircraft operation. Engineers
took advantage of two auxiliary motors working independently of its four powerful
Pratt & Whitney Hornet engines. The motors drove generators to provide electricity
and actuated pumps for the hydraulic controls that ran the unique "booster" system,
the auto pilot, landing gear, wing flaps and de-icers. They also drove the compressors
for cabin air conditioning and heating.
"We manufactured enough electrical current on board to light a large office building,"
Ivar Shogran pointed out. "It was the first time a generating plant of this size
had sprouted wings."
Patterson had gambled and won, too, when he took the powerplant problem to his
friend, Fred B. Rentschler, head of Pratt & Whitney. Rentschler had been itching
to get his new and powerful Hornet engines into a four-engined airliner and P&W
put everything into the powerplant for the "dream plane."
"The P&W gang at Hartford had made tremendous strides in engine improvement
without which we probably wouldn't have had the power available to get the 32-ton
airplane off the ground," Ivar Shogran emphasizes. "Higher compression ratios, supercharging,
tougher alloys permitting faster crankshaft speeds, redesigned fins for cooling,
did the trick."
The DC-4's 14-cylinder, twin-row, air-cooled radials totaled more than 5,600
horsepower - equal to the output of two diesel locomotives. The fact that Patterson
and Douglas and the others had taken the bold step to produce an airframe of this
size had spurred the engine people to produce the high horsepower engines. It was
the beginning of a new era in aircraft engine development. The DC-4 was the flying
One thing was certain. There was plenty of power at his finger tips when veteran
Douglas test· pilot and Vice-President of Sales, Carl Cover, climbed into the pilot's
seat and took the new sky giant aloft on its maiden voyage.
It was June 7, 1938.
The plane came through with flying colors. When Cover landed he told Douglas-"She
flies herself ... I just went along for the ride!"
Early in the test program the Douglas Company released performance figures: Useful
load, 20,000 pounds; High speed, 240 miles per hour (faster than any bomber of that
period); Cruising altitude 22,900 feet; Absolute ceiling, 24,000 feet, almost five
miles above the earth; Maximum range, 2,200 miles.
Although the big plane flew in 1938, it was not until May the following year
that Douglas turned the DC-4 over to United Air Lines and the other participating
airlines for their flight evaluation tests. United, American, TWA, Eastern, Pan
American, in that order, assigned their own flight test crews to put the plane through
Up and down the airways, east, west, north and south, landing at big metropolitan
cities and intermediate populated areas - wherever airports were able to accept
it-the plane made its public debut. Everywhere it went, people looked at the giant
with awe, almost disbelief that such a huge machine could lift itself into the sky
and hurtle through the air a such amazing speeds. Surely, this was the modern "magic
Pilots liked it and praised it. Famous plane designer and racing pilot Benny
Howard ("Mister Mulligan") flew the plane for United. Howard really "wrung" it out.
At Cheyenne, Wyoming, elevation 6,200 feet, he roared down the runway in take-off,
reached up and cut out two engines. The plane soared aloft as though nothing had
happened. Watching this unprecedented demonstration of power reserve - and safety
- Jack Herlihy, Vice-President of Operations for United, beamed, "That's the airplane
When Orville Wright, co-inventor of the airplane, walked through the ship during
a stop-over demonstration at Dayton, Ohio, the famous inventor told this reporter,
"This is more of a machine that it is an airplane, a giant complex machine of perfection.
It is a thing of mechanical miracles. Man doesn't fly anymore. The gadgets do all
Airline operations people were sure they had the answer to all their problems.
They were ready for the step into the true Air Age. The DC-4 had the range. She
could fly non-stop from San Francisco to Chicago, high above the treacherous Rocky
Mountains. Tons of radio, communications and navigational equipment aboard led her
across the limitless skies. She had the capacity to haul great loads, a crew of
five, two pilots, flight engineer, steward and stewardess, more than 40 passengers.
There was also plenty of room to spare for mail, express, baggage.
More important, perhaps, she could do all of this for about the same operational
cost per seat mile as the DC-3. Where cost did go up, increased performance and
capability made it almost negligible .
The results of the airline test programs brought about many recommendations for
improvements in passenger comfort and in design suggestions. The maintenance people,
for instance, wanted a single rudder configuration. Douglas had already worked this
out. The principal change, however, was from the passengers who wanted a pressurized
cabin. Douglas had already anticipated this and the pressurization system was "on
There had been a split among the quintet of airlines who were underwriting the
DC-4 project. TWA and Pan American had "bought" the Boeing 307 "Stratoliners" -
first of the pressure-cabin passenger airliners. The Boeings weighed 1,000 pounds
under the weight restriction stipulated in the original agreement. Eastern also
pulled out. Unless they had a pressurized cabin airliner to compete with the Boeings,
United and American would be left holding the sack. They had to ante up the $300,000.
With that much money invested, Douglas wasn't going to let them down. He had
matched it and more. The DC-4 production model would have a pressurized cabin. American
and United placed orders for the new models.
A Japanese mission was in Santa Monica shopping around for a big plane to fly
their top brass from spot to spot in their so-called Co-Prosperity Sphere. The Japs
bought the original DC-4. On its initial flight with Japanese crews aboard the tripled-tailed
"Flying Hotel" plunged into Tokyo bay after take-off.
It had served its purpose well for Douglas. The plant was gearing up for production
of the modified DC-4 airliners, already they were being called DC-6's. The fact
is, Douglas really never built another DC-4. History had other ideas.
This was the year 1940, Great Britain was fighting for her life. France had fallen.
The Luftwaffe was relentlessly bombing Coventry, Birmingham, London and other English
cities. England, alone, stood between the U. S. and Hitler's dream of world conquest.
Britain needed bombers, not transport planes. On a visit to the Douglas plant
USAAF General "Hap" Arnold saw the work progressing on the modified DC-4 transports.
A few days later Douglas got a teletype directing him to stop work on the big transport
planes. United and American were asked to cancel their orders.
It riled the Scotsman's blood. He was already producing bombers for Britain faster
than the planes could be delivered across the Atlantic. It was his plant and if
he wanted a Board of Directors in the War Department that's where he would have
gone for them in the first place. Besides, Don Douglas believed there would be a
need in the coming war for a big plane to do an aerial logistics job.
"We're going to keep on building the DC-transport," Douglas told Raymond. "We'll
step up, the bombers and the other military ship production. But, we're going to
build the big one. They're going to need a big cargo plane before this war's over
and this is it."
Then something else happened. The Germans, with a great aerial armada invaded
the island of Crete. U. S. military observers returned with breathless reports of
giant gliders and huge four-engined transport planes that made the invasion lightning
swift and highly successful.
The teletype from Washington clacked out another urgent message - "Top priority
on the big transports."
Overnight, the Army air chiefs had concluded that the DC-4 was exactly what the
rapidly growing Air Force needed for global air transport. The DC-4 prototype became
the Douglas Skymaster. The Air Force called it the C-54. The Navy designated it
R-5D. It became the aerial workhorse of the war, carrying VIP's, troops, ammunition,
all kinds of cargo to the far four corners during the five years that followed.
After the war, many of the big cargo planes were converted into airliners and
they became DC-4's within the air transport industry. These rebuilt and refurbished
C-54's, all plushed up as interim airliners, carried the bulk of air traffic until
the DC-6's were ready. Then followed a long line of famous sky giants - the DC-6,
the DC-7, the DC-7C's, and finally the D-8 jets.
But they all owe their lineage to the first of the big ones - the tripled-tailed
Posted July 4, 2020