| XNBL-1 "Barling Bomber" | |
|---|---|
 | |
| General information | |
| Type | Heavy bomber |
| Manufacturer | Wittemann-Lewis |
| Designer | |
| Primary user | United States Army Air Service |
| Number built | 1 |
| History | |
| First flight | 22 August 1923 |
| Retired | 1928 |
The Wittemann-Lewis NBL-1 "Barling Bomber" [1] was an experimental long-range, heavy bomber built for the United States Army Air Service in the early 1920s. Although unsuccessful, it was an early attempt at creating a strategic bomber.
Development of the XNBL-1 (Experimental Night Bomber, Long Range) Barling Bomber [1] is generally attributed (the press called it "Mitchell's Folly") to William "Billy" Mitchell, and was designed by Walter H. Barling. [2] [3]
Barling [4] had previously designed the Tarrant Tabor, which was similar in concept but was destroyed in a fatal nose-over crash on its first flight in 1919. The nose-over had probably been caused by the high placement of two of the six engines – a compromise due to the lack of more powerful engines. Like the Tabor, the Barling Bomber was a large six-engined triplane with a cigar-shaped fuselage. Unlike its predecessor, the Barling had all of its engines mounted level with the fuselage. The aircraft used three wings, but was not actually a triplane in the conventional sense. More correctly, it was a two-and-a-half wing aircraft. The middle wing had no control surfaces, and was shorter and narrower than the two primary wings. The top and bottom wings had a chord of 13 ft 6 in (4.11 m), and each had a surface area of about 2,000 sq ft (190 m2). The stabilizer and elevator surfaces were 575 sq ft (53.4 m2) with an 8 ft (2.4 m) chord. The fins and rudders looked like a box kite, and had a surface area of 250 sq ft (23 m2). The undercarriage consisted of 10 wheels, including two wheels mounted towards the front of the aircraft (to prevent a nose-over on takeoff) and a tail skid. [2]
The Engineering Division was forced to use Liberty engines because of an abundant supply of the engines. [N 1] To power the Barling, four 420 hp Liberty engines were mounted between the lower and middle wings in a tractor arrangement, and an additional two in a pusher position. The gross weight of the bomber was 42,569 lb. It had a fuel capacity of 2,000 gallons, and carried 181 gallons of oil. [2] [3]
Two pilots occupied separate cockpits either side of the fuselage, while a bombardier sat in the nose. One or two flight engineers sat behind the cockpits to help tend the engines. A radio operator and a navigator were seated next to them. [6] [7]
The specification for the aircraft called for it to carry a 5,000 lb (2,300 kg) bomb load at 10,000 ft (3,000 m) altitude while maintaining a speed of 100 mph (160 km/h). [2] The Barling was armed with seven .30-caliber Lewis machine guns, which were operated from five stations. [8] The gun stations gave the gunners a field of fire that covered practically the whole area around the bomber. Bomb racks were mounted in an enclosed bomb bay beneath the gasoline tanks. The bomb bay could accommodate any bomb in the air service inventory, including the 2,000- and 4,000-lb bombs that had been designed specifically to sink a battleship. The Barling incorporated bomb bay doors on the bottom of the fuselage, one of the first aircraft to feature such an innovation. [2]
The contract for the bomber was awarded to Witteman-Lewis, located in Hasbrouck Heights, New Jersey; the contract was for $375,000 and specified the construction of two aircraft. As costs rose with changes to the design, the second aircraft was cancelled, and in October 1922 when the prototype was completed the cost was $525,000 for the single aircraft. The Army Air Corps refused to cover the overrun, and soon after delivery of the aircraft Witteman-Lewis went out of business. [2] [3]
On 22 August 1923, the Barling Bomber made its maiden flight from Wilbur Wright Field in Fairfield, Ohio. At the time, it was comparable in size to the German Riesenflugzeug and Italian Caproni Ca.4 heavy bombers and remains large even by today's standards, however it was severely overbuilt and weighed significantly more than other aircraft at the time of a similar size, to the detriment of its performance.
On its first flight, it was piloted by Lt. Harold R. Harris, and Lt. Muir S. Fairchild, future U.S. Air Force Vice Chief of Staff. The flight engineer was Douglas Culver. Barling flew along as a passenger. Critics had claimed that the bomber would roll all the way to Dayton before it ever took off, but the aircraft became airborne after a 13-second, 960 ft (290 m) takeoff run. The flight lasted 28 minutes and reached an altitude of 2,000 ft (610 m). [2] [3]
On 3 October 1924, the aircraft set a duration record of 1 hour 47 minutes for an aircraft "with 8,820 lbs (4,000 kgs [sic]) useful load". It also set a record in the same class for altitude with 4,470 ft (1,363 m). [9]
Although capable of carrying a 5,000 lb (2,300 kg) bomb load, it was soon discovered that the aircraft was seriously underpowered, and performance was disappointing. The overly complex structure of three wings and their accompanying struts and bracing wires created so much drag that the six engines couldn't compensate. Fully loaded, the XNBL-1 had a range of only about 170 mi (270 km) with a top speed of 96 mph (154 km/h). In contrast, the "short-range" Martin NBS-1 had a range of about 450 mi (720 km) and could carry a 2,000 lb (910 kg) payload at the same speed. On a flight from Dayton, Ohio to a scheduled appearance at an airshow in Washington, DC, the Barling Bomber failed to achieve enough height to get over the Appalachian Mountains and had to turn around. [2] [3]
A problem with water collecting in the aircraft's wings during rainstorms necessitated the construction of a special hangar at a cost of $700,000. The hangar was constructed in 1925 at the nearby Fairfield Air Depot. [2]
Although the XNBL-1 was not put into production, it had advanced features such as aluminum fuselage components, adjustable [10] multi-wheel undercarriage, separate compartments for crew, a flight engineer, electrical instruments and advanced engine controls. One unusual feature was that the incidence of the tailplane could be adjusted in flight using a lever in the cockpit. [11] The XNBL-1 was the largest aircraft built in the United States until the Boeing XB-15 in 1935.
Frequently characterized by opponents of airpower as "Mitchell’s Folly" (after Brig.-Gen. William "Billy" Mitchell, who had championed the project), in 1927, the aircraft was disassembled by Air Service personnel and placed in storage at the Fairfield Air Depot. In 1929, then-Major Henry H. "Hap" Arnold was assigned as commander of the Fairfield Air Depot. He submitted a Report of Survey to the Office of the Chief of Air Corps, asking permission to salvage parts from the stored bomber, and burn the rest. Several members of Congress still held an interest in the aircraft, and the request was denied. Maj. Arnold then submitted a similar request to burn the "XNBL-1", omitting any mention of the name "Barling". That request was approved, and the bomber was burned at Fairfield in 1930. [2] [3] Two of the bomber's wheels survived and are on display at the National Museum of the United States Air Force. [12]
Although the Barling Bomber was a failure, it introduced the use of large strategic bombers to the US military. Even Gen. "Hap" Arnold, who ordered it destroyed, later stated "if we look at it without bias, certainly [the Barling] had influence on the development of B-17s... and B-29s." [13]
United States 
Data from Witteman-Lewis XNBL-1 Barling Bomber [14]
General characteristics
Performance
Armament
Related development
Aircraft of comparable role, configuration, and era
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