Witteman-Lewis XNBL-1

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, a U.S.Army Air Service General and most vocal advocate of strategic airpower, who in 1919 discovered Walter H. Barling, who had previously worked for the Royal Aircraft Factory. Mitchell asked Barling to design a bomber capable of carrying enough bombs to sink a battleship. Mitchell's goal was to demonstrate the effectiveness of airpower by sinking a battleship from the air, and needed a large, strategic bomber in order to accomplish this feat. Mitchell projected the cost of two prototype bombers at $375,000. On 15 May 1920, the Army Engineering Division sought bids for the construction of a bomber based on Barling's sketches, with the requirement that it be capable of carrying a 5,000 lb (2,300 kg) bomb load, to an altitude of 10,000 ft (3,000 m) at a speed of no less than 100 mph (160 km/h).[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 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]

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]

XNBL-1

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]

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."[12]

• One main tire and one nose tire from the bomber are on display at the National Museum of the United States Air Force in Dayton, Ohio. The tire's original B. F. Goodrich marking are still clearly visible. The main tire is nearly 48 in (1.2 m) in diameter.

 United States

• United States Army Air Service

The XNBL-1 in flight

Data from Witteman-Lewis XNBL-1 Barling Bomber[13]

General characteristics

• Crew: Seven (two pilots, five gunners)
• Length: 65 ft 0 in (19.81 m)
• Wingspan: 120 ft 0 in (36.58 m)
• Height: 27 ft 0 in (8.23 m)
• Wing area: 4,017 sq ft (373.2 m²) [14]
• Empty weight: 27,132 lb (12,307 kg) [14]
• Gross weight: 42,569 lb (19,309 kg) [14]
• Powerplant: 6 × Liberty L-12A , 420 hp (313 kW) each

Performance

• Maximum speed: 96 mph (155 km/h, 83 kn) at sea level
• Cruise speed: 61 mph (98 km/h, 53 kn)
• Range: 170 mi (274 km, 150 nmi) with full bomb load (varied by bomb load carried)
• Service ceiling: 7,725 ft (2,355 m)

Armament

• Guns: 7 × .30 cal (7.62 mm) machine guns
• Bombs: Up to 5,000 lb (2300 kg) bomb load

Related development

• Tarrant Tabor

Aircraft of comparable role, configuration, and era

• Handley Page V/1500
• Zeppelin-Staaken R.VI

Related lists

• List of bomber aircraft
• List of military aircraft of the United States

Notes

Bibliography

Wikimedia Commons has media related to Witteman-Lewis XNBL-1.

• Wittemann-Lewis NBL-1 "Barling Bomber" – USAF Museum
• Maxwell AFB