Douglas XB-19

The XB-19 on its first flight. Serial Number 38-471. 

In 1941, the Douglas company built and flew the largest aircraft that would take to the skies until 1946. Only one was built, and it never flew against an enemy, but the aircraft that Douglas built became a symbol of pre-war American air power.

The XB-19 was the result of a U.S. Army Air Corps project started in February 1935 to produce a very long-range bomber aircraft, mostly to see how far the tech of the day could go. The program was given the designation Project D and was classified secret.

Douglas Aircraft and Sikorsky Aviation were the only two companies interested in the project, and contracts were made covering the preliminary designs and mockups, with the option to purchase a complete aircraft if the early work looked promising. On July 9th, 1935, the Douglas product was given the designation XBLR-2 [Experimental Bomber Long Range], and the company estimated that the aircraft could be finished by March 31st, 1938. The design contract was approved on October 31st, 1935, and work began. 

The next year in March 1936, the wooden mockups of the aircraft from both Sikorsky and Douglas were inspected. Douglas's offering was seen as being superior, so Sikorsky's contract was canceled with a payment of $103,000.

Douglas workers assembling the leading edge of a wing, on scaffolding 60 feet in the air. 

The XBLR-2 was a strikingly advanced aircraft for the day and incorporated many features that had never been seen before on an American combat aircraft. These included tricycle style landing gear, which were tested on a loaned OA-4 Dolphin, and proved so successful that Douglas added them to the upcoming DC-4 and A-20 designs. Also included were power operated turrets and a dedicated tail gunner position. The power turrets were tested successfully, but the tail gun was seen as being of questionable value at the time.

At first, the XBLR-2, and the Sikorsky design were to use 1,600 hp Allison XV-4320-1 liquid-cooled inline engines. These were two of the V-1710 engines joined together. These were replaced on November 2nd, 1936 with the Wright R-3350 radial engine, producing 2,000 horsepower each, and were air cooled.

The mighty Wright R-3350 engine drove aircraft like the B-29, the A-1 Skyraider, and the Lockheed Constellation. 

Work continued with a contract for additional detailed designs and tests on September 29th, 1936. A contract change for a prototype designated XB-19 was dated to November 19th, 1937, but wasn’t approved until March 8th, 1938. This was the time that the serial number 38-471 was assigned to the aircraft. 

The XB-19 under assembly in three sections, nose, midsection and wings, and tail. They were carefully joined together after. 

This photo shows the general way that the XB-19 was pieced together from its sections. 

Meanwhile, the USAAF was looking into other aircraft as well. Proposals from Douglas and Boeing were presented in March 1938, for four-engined heavy bombers with tricycle landing gear, and using the R-2180 Twin Hornet engine (1,400hp). The Boeing Model 316D which was designated the Y1B-20 in June 1938, was a large high-wing, 80,000 pound, ten place, seven gun, 152' wingspan, bomber with a pressurized cabin. Douglas offered a craft derived from the DC-4 transport, with a low wing, 71,000 pounds, nine crew, 6 guns, and a range of 1,000 miles with a bombload of 20,000 pounds. By June 29th, it was decided that prototypes would be too expensive to procure, so the Y1B-20 was dropped, and Douglas sold the DC-4 prototype to Japan. The Japanese derived their G5N-1 from this aircraft, given the reporting name 'Liz'. Their engine designs weren't up to the task though, so only six G5Ns were ever built, and were always underpowered.

Leaving the chronic issues of large Japanese aircraft, Douglas was having its own problems. The company recommended canceling the contract on August 30th, as the XB-19 was taking up massive amounts of money and time. Its weight was also climbing incessantly, and the design that was state of the art in 1936 was already starting to fall behind. The Army was insistent though, so Douglas continued with the $1.4 million contract. Actual flight tests were needed to understand how to build and handle aircraft of the XB-19's size.

After six years in development, and three years behind schedule, the XB-19 took to the sky for the first time from Clover Field in Santa Monica on June 27th, 1941. On this first flight, the XB-19 had a crew of seven men, commanded by Major Stanly M. Umstead, and flew to March Field to be turned over to the Army for evaluation in 56 minutes. In 1940, the Army had dropped the secret classification for the project, and the XB-19 had become a popular sensation. So much so, that President Roosevelt himself telegraphed Donald Douglas a congratulation on the first flight of the XB-19. This popularity is where many of the photographs in this post come from, and the extensive documentation is immensely valuable.

The XB-19 joined together in the Douglas factory.

On January 1st, 1939, its armament was specified, a formidable collection of firepower for the day. Two 37mm cannons with 50 rounds per gun, five M2 .50 caliber machine guns with 200 rounds per gun, and six M1919 .30 caliber machine guns with 600 rounds per gun. The bomb bay could carry eight 2,000 pound bombs, sixteen 1,600 pound bombs, or thirty 600 pound bombs. Additionally, wing racks could be added to carry up to ten more 2,000-pound bombs could be fitted, though this cut the bombers range significantly. All told, the XB-19 could carry 37,100 pounds of bombs. 

Douglas workers attaching the control cables in the cockpit. Note how spacious it is. 

But, the XB-19 had no armor or self-sealing fuel tanks, as these were not requirements for Army aircraft until 1940. Though these would probably be added if it was decided to put the XB-19 into mass production. 

Up to 16 men made up the crew of the bomber. In the nose was a gunner with a 37mm cannon in a power-operated turret, with the bombardier and another gunner with a pair of .30 MGs below and behind him. Above them in the main compartment were the pilot and copilot, along with the plane commander, navigator, engineer, and the radio operator. The top turret was equipped with a 37mm and a .30 and was operated by the top gunner. Past the bomb bay were the two waist gunners, a gunner for the upper rear turret, and a belly gunner, each of which single .50 caliber gun. Another two men were in the tail compartment, with two .30 caliber guns on each side of the stabilizer, and another .50 caliber machine gun at the very end of the tail. For long missions, the space above the bomb bay had six bunks and eight seats for passengers or relief crew, and there was even a complete galley for the crew in the tail to make hot meals. The sleeping cabin and the main cabin were both soundproofed and heated. Passages were installed in the wings to allow direct access to the rear of the engines, and the aircraft was boarded via a dropdown ladder from the bottom of the fuselage.

Douglas workers dusting the fuselage in the factory. 

The XB-19 had several other significant features for the time. Powered controls for the pilot and copilot, as the control surfaces were too large to be moved effectively by a regular human. The rudder alone had an area of 237 ft^2. The ailerons were made of two sections to prevent jamming, as the wings could bend at the tips by up to 12 feet at times. Two small engines were in the fuselage to provide power to start the main engines so that the XB-19 could operate hoists for its own engines or 16' diameter propellers. The electrical system produced 5 KW of power for a fire alarm system, a 24 station telephone system, and a loudspeaker system. No parts of the XB-19 were pressurized, so an oxygen system that piped to all parts of the bomber was installed, with the main system located in the tail section. 

The XB-19 outside, the hole for the forward top turret can be seen. The sheer size can be clearly seen, as can the operating engine. 

Even with its formidable armament, the XB-19 was more valuable as a testbed for large bombers than it was as a weapon of war. This was valuable experience for the B-29 and the B-36 that were under development at the time.

The XB-19 in flight in 1941. It looks like the top turrets are not fitted in this photo. 

Specifications: Douglas XB-19 

4x Wright R-3350-5 engines, 2,000 hp at takeoff, 1,500 hp at 15,700'

Dimensions
     Wingspan: 212'

     Length: 132' 2'' 

     Height: 42' 9''

     Wing Area: 4285ft^2
Weight

     Empty Weight: 84,431 lb

     Gross Weight: 140,000 lb

     Max. Weight: 162,000 lb

     Fuel Capacity:
          Internal: 10,350 gallons
          With addtional tanks in bomb bay: 11,174 gallons
Performance

     Top Speed: 224 MPH at 15,700', actual 204 MPH

     Cruising Speed: 135 MPH

     Landing Speed: 73 MPH

     Absolute Ceiling: 24,500'

     Service Ceiling: 23,000'

     Rate of Climb: 545'/minute

     Range:

          7,300 miles with 6,000 lb bomb load

          7,900 miles maximum

The XB-19 in a hanger on March 18th, 1941. 

In December 1941, the Japanese attacked Pearl Harbor and brought the United States into the Second World War. As a result, the XB-19 was given a camouflage paint scheme and went with loaded guns during its last four flights in California. On January 23rd, 1942, the XB-19 was flown to Wright Field in Dayton Ohio.

Flight testing went well, though some issues were discovered. Improvements to the brakes were added, and the cooling gills for the engines had to be kept open during long flights, which reduced the top speed by 20 MPH. With that done, the Army accepted the XB-19 in June 1942, paying Douglas $1.4 million. But by then, Douglas had spent almost $4 million on the aircraft, resulting in a loss of around $2.5 million in 1942 dollars. Altogether, four acres of drawings had been made, 2,000,000 hours of work by 200 engineers and other specialists had gone into the XB-19. 

The Allison V-3420-11. Less than 200 were made, as the end of WWII put a stop to many of the aircraft that would have used it. 

In 1943, the Wright engines were replaced with the turbosupercharged Allison V-3420-11, capable of producing 2,600 horsepower. The XB-19 was redesignated the XB-19A and used as a cargo aircraft until its last flight on August 17th, 1946. That flight took it from Wright Field to Davis-Monthan Field in Arizona, where it was stored until being scrapped in June 1949. One way or another, its nose section ended up in a Los Angles scrapyard and was there through 1955 at the latest. 

The XB-19A in flight, in its camouflage paint scheme. The difference in engines can be clearly seen, and the apparent deletion of the aft top turret. 

Specifications: Douglas XB-19A

Dimensions same as XB-19
Weight

     Empty Weight: 92,400 lb

     Gross Weight: 140,230 lb

     Fuel Capacity: 6400 gallons*
Performance

     Top Speed: 265 MPH at 20,000' 

     Cruising Speed: 185 MPH

     Service Ceiling: 39,000'

     Range: 4200 miles with 2,500 lb bomb load

The XB-19A at Davis-Monthan before being scrapped.

The nose of the scrapped XB-19A in 1949. The detail of the nose turret can be seen. 

What is Left

Despite being scrapped, two of its massive tires remain to this day. One is located in the Museum of the United States Air Force, the other is apparently in the Hill Aerospace Museum in Ogden, Utah.

The tires of the XB-19 are still huge, though not the largest in the museum. That goes to the 110'' XB-36's tire in the Cold War Gallary. The main tires are eight feet in diameter (96'') and are of 24 ply construction. 150 miles of rayon cord and three miles of steel wire are used in the construction. The one in the Museum of the United States Air Force was donated by the Ben W. Colburn company of Tulare, California. It is located in the Early Years Gallary of the Museum. 

*I don't think that this is correct, as the internal capacity was 10,350 gallons. This might be additional fuel capacity, a loss of capacity, but I'm not sure. No matter what, I think that the listed 10,350 is still a viable number for internal fuel capacity.

Sources:

American Combat Aircraft, Third Enlarged Edition. Wagner, Ray

http://www.joebaugher.com/usaf_bombers/b19.html

Uncle Sam Builds a Europe and Back. Popular Science, October 1940. Boone Andrew

Popular Mechanics, September 1941

Man O' War With Wings. Popular Mechanics

Photos:

Wikipedia Commons

Uncle Sam Builds a Europe and Back. Popular Science, October 1940. Boone Andrew

Popular Mechanics, September 1941

Man O' War With Wings. Popular Mechanics

Own work