30 July 1939: Major Caleb Vance Haynes, United States Army Air Corps, with Captain William D. Old, Master Sergeant Adolph Cattarius and Staff Sergeant William J. Heldt, flew the Boeing XB-15 experimental long range heavy bomber to a Fédération Aéronautique Internationale (FAI) World Record for Greatest Payload Carried to a Height of 2,000 meters. The XB-15 carried 14,135 kilograms (31,162 pounds) to an altitude of 6,562 feet over Fairfield, Ohio. The flight set a second record by carrying 10,000 kilograms (22,046 pounds) to an altitude of 8,228 feet (2,508 meters). Both records were certified by the National Aeronautic Association, the American organization representing the FAI.


Major Caleb V. Haynes, Captain William D. Old, Master Sergeant Adolph Cattarius and Staff Sergeant William J. Heldt, crew of the record-setting Boeing XB-15. (FAI)


FAI Record File Num #8739 [Direct Link]

Status: ratified – superseded since approved

Region: World

Class: C (Powered Aeroplanes)

Sub-Class: C (Aviation with engine)

Category: General

Group: Not applicable

Type of record: Greatest payload carried to a height of 2 000 m

Performance: 14 135 kg

Date: 1939-07-30

Course/Location: Fairfield, OH (USA)

Claimant C. V. Haynes (USA)

Crew W.D. Old, A. Cattarius, W.J. Heldt

Aeroplane: Boeing XB-15 (35-277)

Engines: 4 Pratt & Whitney 1830-11

 

FAI Record File Num #8740 [Direct Link]

Status: ratified – superseded since approved

Region: World

Class: C (Powered Aeroplanes)

Sub-Class: C (Aviation with engine)

Category: General

Group: Not applicable

Type of record: Greatest payload carried to a height of 2 000 m

Performance: 14 135 kg

Date: 1939-07-30

Course/Location: Fairfield, OH (USA)

Claimant C. V. Haynes (USA)

Crew W.D. Old, A. Cattarius, W.J. Heldt

Aeroplane: Boeing XB-15 (35-277)

Engines: 4 Pratt & Whitney 1830-11


Boeing XB-15 35-277


The Boeing Model 294, designated XB-15 by the Air Corps, was an experimental airplane designed to determine if a bomber with a 5,000 mile range was possible. It was designed at the same time as the Model 299 (XB-17), which had the advantage of lessons learned by the XB-15 design team. The XB-15 was larger and more complex than the XB-17 and took longer to complete. It first flew more than two years after the prototype B-17.


Boeing XB-15 35-277, a prototype long-range heavy bomber. (U.S. Air Force)


Designers had planned to use an experimental 3,421.19-cubic-inch-displacement (56.063 liter) liquid-cooled, supercharged and turbosupercharged Allison V-3420 twenty-four cylinder, four-bank “double V” engine which produced a maximum of  2,885 horsepower at 3,000 r.p.m. The engine was not available in time, however, and four air-cooled Pratt & Whitney R-1830 (Twin Wasp) engines were used instead. With one-third the horsepower, this substitution left the experimental bomber hopelessly underpowered as a combat aircraft.


Boeing XB-15 35-277. (U.S. Air Force)


The XB-15 was a very large four-engine mid-wing monoplane with retractable landing gear. It was of aluminum monocoque construction with fabric-covered flight control surfaces. The XB-15 had a ten-man crew which worked in shifts on long duration flights.

The prototype bomber was 87 feet, 7 inches (26.695 meters) long with a wingspan of 149 feet (45.415 meters) and overall height of 18 feet, 1 inch (5.512 meters). The airplane had an empty weight of 37,709 pounds (17,105 kilograms) and maximum takeoff weight of 70,706 pounds (32,072 kilograms)—later increased to 92,000 pounds (41,730 kilograms).

As built, the XB-15 was powered by four air-cooled, supercharged, 1,829.39-cubic-inch-displacement (29.978 liter) Pratt & Whitney R-1830-11 (Twin Wasp S1B3-G) two-row 14-cylinder radial engines, rated at 850 horsepower at 2,450 r.p.m. and 5,000 feet ( meters), and 1,000 horsepower at 2,600 r.p.m. for take off., each. They turned three-bladed controllable-pitch propellers through a 3:2 gear reduction. The R-1830-11 was 4 feet, 8.66 inches (1.439 meters) long with a diameter of 4 feet, 0.00 inches (1.219 meters), and weighed 1,320 pounds (599 kilograms).


Boeing XB-15 35-277


These gave the experimental airplane a maximum speed of 197 miles per hour (317 kilometers per hour) at 5,000 feet (1,524 meters) and a cruise speed of 152 miles per hour (245 kilometers per hour) at 6,000 feet (1,829 meters). The service ceiling was 18,900 feet (5,761 meters) and maximum range was 5,130 miles (8,256 kilometers).

The bomber could carry a maximum of 12,000 pounds (5,443 kilograms) of bombs in its internal bomb bay, and was armed with three .30-caliber and three .50-caliber machine guns for defense .

Only one XB-15 was built. During World War II it was converted to a transport and redesignated XC-105. In 1945 it was stripped and abandoned at Albrook Field, Territory of the Canal Zone, Panama.



Boeing B-15 35-277 arrives in Panama (49509 A.C.)


On the main photo: A color transparency of the Boeing XB-15