Tag Archives: Pratt & Whitney R-1830-11

2 August 1939

Major Caleb V. Haynes, U.S. Army Air Corps, with Captain William D. Old; Walter G. Bryte, Jr.; A.C. Brandt; Master Sergeant Adolph Catarius; Technical Sergeant Daniel L. spice; Staff Sergeant James E. Sands, the distance record-setting crew of the Boeing XB-15 35-277. (FAI)
The speed-distance record-setting crew of the Boeing XB-15 experimental long range bomber, left to right: Major Caleb V. Haynes, U.S. Army Air Corps, with Captain William D. Old; Walter G. Bryte, Jr.; A.C. Brandt; Master Sergeant Adolph Cattarius; Technical Sergeant Daniel L. Spicer; Staff Sergeant James E. Sands. (FAI)

2 August 1939: The Boeing Model 294, designated by the U.S. Army Air Corps as the XB-15, serial number 35-277, flown by a crew led by Major Caleb Vance Haynes, set a Fédération Aéronautique Internationale (FAI) World Record for Speed Over a Closed Circuit of 5000 Kilometers With 2000 Kilogram Payload, when they flew the experimental long range heavy bomber a distance of 3,109 miles at an average speed of 267.67 kilometers per hour (166.32 miles per hour) while carrying a payload of 2,000 kilograms (4,409.25 pounds).¹

The other members of the XB-15 crew were Captain William D. Old, Walter G. Bryte, Jr., A.C. Brandt, Master Sergeant Adolph Cattarius, Staff Sergeant William J. Heldt, Technical Sergeant Daniel L. Spicer and Staff Sergeant James E. Sands.

The Boeing XB-15, 35-277, flies past teh Wright Brothers memorial at the kill Devil Hills, Kitty Hawk, North Carolina. (U.S. Air Force)
The Boeing XB-15, 35-277, flies past the Wright Brothers National Memorial at the Kill Devil Hills, Kitty Hawk, North Carolina. (U.S. Air Force)

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.

The Boeing Model 294 (XB-15) at Boeing Field, Seattle, Washington, circa 1937. (The Boeing Company)

Designers had planned to use an experimental 3,421.194-cubic-inch-displacement (56.063 liter) liquid-cooled, supercharged and turbosupercharged Allison V-3420 twenty-four cylinder, four-bank “double V” engine. It 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. (The Douglas XB-19 was retrofitted with V-3420s in 1942, and re-designated XB-19A.)

Boeing XB-15 at NACA Langley Memorial Aeronautical Laboratory, 13 September 1938. (NASA)

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).

The XB-15’s wings used a symmetrical airfoil and were very highly tapered (4:1 from root to tip). They had an angle of incidence of 4½° and 4½° dihedral. The total area was 2,780 square feet (258.271 square meters). A contemporary aeronautical publication wrote, “The airfoil provides constant center of pressure, minimum profile drag with flaps up and high maximum lift with flaps down.” The XB-15’s wings were adapted by Boeing for the Model 314 Clipper flying boat.

Boeing XB-15 in flight. (U.S. Air Force)050406-F-1234P-053

As built, the XB-15 was equipped with 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 with a compression ratio of 6.7:1. The R-1830-11 was rated at 850 horsepower at 2,450 r.p.m. and 5,000 feet (1,524 meters), and 1,000 horsepower at 2,600 r.p.m. for take off. 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).

The experimental airplane had a cruise speed of 152 miles per hour (245 kilometers per hour) at 6,000 feet (1,829 meters), and a maximum speed of 200 miles per hour ( kilometers per hour) at 5,000 feet (1,524 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 re-designated XC-105. In 1945 35-277 was stripped and abandoned at Albrook Field, Territory of the Canal Zone, Panama.

The Boeing XB-15 experimental long-range heavy bomber flies in formation with a Boeing YP-29 pursuit. (U.S. Air Force)
The Boeing XB-15 experimental long-range heavy bomber flies in formation with a Boeing YP-29 pursuit. (U.S. Air Force)

¹ FAI Record File Number 10865

© 2018, Bryan R. Swopes

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30 July 1939

A color transparency of the Boeing XB-15
A color transparency of the Boeing XB-15 in flight near Mitchel Field, Long Island, New York, circa 1941. (Rudy Arnold Collection, National Air and Space Museum)

30 July 1939: Major Caleb Vance Haynes, Air Corps, United States Army, 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 2,000 meters (6,562 feet) over Fairfield, Ohio.¹ The flight set a second record by carrying 10,000 kilograms (22,046 pounds) to an altitude of 8,228 feet (2,508 meters).² 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)
Boeing XB-15 35-277 at NACA Langley Memorial Aeronautical Laboratory, 13 September 1938. (NASA)
Boeing XB-15 35-277
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.

Designers had planned to use an experimental 3,421.194-cubic-inch-displacement (56.063 liter) liquid-cooled, supercharged and turbosupercharged Allison V-3420 twenty-four cylinder, four-bank “double V” engine. It 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. (The Douglas XB-19 was retrofitted with V-3420s in 1942, and re-designated XB-19A.)

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

A ¼-scale model of the Boeing XB-15 inside the Full-Scale Wind Tunnel at the National Advisory Committee for Aeronautics (NACA) Langley Memorial Aeronautical Laboratory, Hampton, Virginia. The model has a wingspan of 37.3 feet (11.37 meters). (NASA)

The XB-15’s wings used a symmetrical airfoil and were very highly tapered (4:1 from root to tip). They had an angle of incidence of 4½° and 4½° dihedral. The total area was 2,780 square feet (258.271 square meters). A contemporary aeronautical publication wrote, “The airfoil provides constant center of pressure, minimum profile drag with flaps up and high maximum lift with flaps down.” The XB-15’s wings were adapted by Boeing for the Model 314 Clipper flying boat.

As built, the XB-15 was equipped with 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 with a compression ratio of 6.7:1. The R-1830-11 was rated at 850 horsepower at 2,450 r.p.m. and 5,000 feet (1,524 meters), and 1,000 horsepower at 2,600 r.p.m. for take off. 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
Boeing XB-15 35-277

The experimental airplane had a cruise speed of 152 miles per hour (245 kilometers per hour) at 6,000 feet (1,829 meters), and a maximum speed of 200 miles per hour ( kilometers per hour) at 5,000 feet (1,524 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 re-designated XC-105. In 1945 35-277 was stripped and abandoned at Albrook Field, Territory of the Canal Zone, Panama.

Boeing XC-105 35-277 in Panama
Boeing B-15 35-277 arrives in Panama (49509 A.C.)

¹ FAI Record File Number 8739

² FAI Record File Number 8740

© 2018, Bryan R. Swopes

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15 October 1937

The Boeing XB-15 takes off on its first flight, Boeing Field, 15 October 1937. (U.S. Air Force)

15 October 1937: Test pilot Edmund Turney (“Eddie”) Allen, a consulting engineer to Boeing, and Major John D. Korkille, Air Corps, United  States Army, made the first flight of the prototype Boeing XB-15, 35-277, at Boeing Field, Seattle, Washington. Major Corkille reported that the airplane “handled easily and maneuvered readily.”

The flight deck of the Boeing XB-15. The radio operator’s station is on the left, and the navigator’s on the right. (The Boeing Company)

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 (8,047 kilometers) 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.

The Boeing Model 294 (XB-15) at Boeing Field, Seattle, Washington. The prototype bomber was rolled out for engine tests, 27 September 1937. (The Boeing Company)

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

Boeing XB-15 35-277

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 Twin Wasp S1B3-G (R-1830-11) two-row 14-cylinder radial engines, rated at 850 horsepower at 2,450 r.p.m. at 5,000 feet (1,524 meters), and 1,000 horsepower at 2,600 r.p.m. for take off. The engines 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).

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 Boeing XB-15 experimental long-range heavy bomber flies in formation with a Boeing YP-29 pursuit. (U.S. Air Force)

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.

The XB-15 set several Fédération Aéronautique Internationale (FAI) world records:  On 30 July 1939, the XB-15 carried 14,135 kilograms (31,162 pounds) to an altitude of 2,000 meters (6,562 feet) over Fairfield, Ohio.¹ The same flight set a second record by carrying 10,000 kilograms (22,046 pounds) to an altitude of 8,228 feet (2,508 meters).² On 2 August 1939, the XB-15 set a World Record for Speed Over a Closed Circuit of 5000 Kilometers With 2000 Kilogram Payload, at an average speed of 267.67 kilometers per hour (166.32 miles per hour).³

Boeing XB-15 35-277. (LIFE Magazine)

¹ FAI Record File Number 8739

² FAI Record File Number 8740

³ FAI Record File Number 10865

© 2017, Bryan R. Swopes

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21 September 1937

Jackie Cochran sits in the cockpit of the Seversky SEV-S1, NR18Y, September 1937. Note how the landing gear retracts straight to the rear in this early version. It would be modified to retract inward to the airplane’s centerline, and more effectively streamlined in the future. (San Diego Air and Space Museum Archives)

21 September 1937: Jackie Cochran flew the Seversky Aircraft Corporation SEV-S1, civil registration NR18Y, over a 3 kilometer course at Detroit Wayne County Airport, Romulus, Michigan, averaging 470.40 kilometers per hour (292.29 miles per hour). This was a new Fédération Aéronautique Internationale (FAI) world speed record.¹

The Seversky SEV-S1 Executive was an improved version of the P-35 fighter, which was designed by Major Alexander P. de Seversky. The P-35 was the first U.S. Army Air Corps single-engine airplane to feature all-metal construction, an enclosed cockpit and retractable landing gear.

Seversky SEV-S1 NR18Y. (San Diego Air and Space Museum Archives)

The airplane had been built as the SEV-2XP, a two-place monoplane with fixed landing gear, and powered by an air-cooled, supercharged 1,666.860-cubic-inch-displacement (27.315 liter) Wright Aeronautical Division GR1670 two-row, 14-cylinder radial engine.

The SEV-2XP was to be a second entry, along with the SEV-1XP, to enter a fly-off against the Curtiss 75 Hawk for the Air Corps fighter contract in 1935. It was damaged, though, while en route Wright Field. The prototype was rebuilt as a single-place airplane with retractable landing gear and a 1,000-horsepower Wright Cyclone GR-1820G4 nine-cylinder engine. In this configuration, the airplane was designated SEV-1XP.

 The Seversky's passenger compartment was accessed through a hatch on the right side of the fuselage. (San Diego Air and Space Museum Archives) Jackie Cochran in the cockpit of the Seversky SEV-2S Executive, NR18Y. Note the passenger windows below and behind the cockpit. (San Diego Air and Space Museum Archives)
The Seversky’s passenger compartment was accessed through a hatch on the right side of the fuselage. (San Diego Air and Space Museum Archives)

After the Air Corps demonstrations, which resulted in an order for 100 Seversky P-35s, NX18Y was again repowered, this time with an air-cooled, supercharged, 1,829.39-cubic-inch-displacement (29.978 liter) Pratt & Whitney Twin Wasp S1B3-G (R-1830-11) two-row 14-cylinder radial engine. The R-1830-11 had a compression ratio of 6.7:1 and was rated at 850 horsepower at 2,450 r.p.m. at 5,000 feet (1,524 meters), and 1,000 horsepower at 2,600 r.p.m. for take off. 87-octane aviation gasoline was required. The engine turned a three-bladed Hamilton-Standard controllable-pitch propeller 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).

With the Twin Wasp, NR18Y’s designation was changed to SEV-S1. Frank Sinclair, Seversky’s chief test pilot, flew it in the 1937 Bendix Trophy Race and the Thompson Trophy Race. (Jackie Cochran flew a Beech Staggerwing in the ’37 Bendix, beating Sinclair and NX18Y by 33 minutes.) Sinclair went on to place fourth in the Thompson pylon race. The Seversky averaged 252.360 miles per hour (406.134 kilometers per hour).

Test pilot Frank Sinclair, Alexander de Seversky and Jackie Cochran with the Seversky SEV-2S, NR70R. (San Diego Air and Space Museum Archives)

¹ FAI Record File Number 12026

© 2018, Bryan R. Swopes

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15 September 1939

Jackie Cochran with her record-setting Seversky AP-7A, NX1384. (FAI)

15 September 1939: Jackie Cochran set a Fédération Aéronautique Internationale (FAI) World Speed Record flying a Seversky AP-7A, civil registration NX1384, over a 1,000 kilometer course, from Burbank, California, to San Mateo, approximately 20 miles (32 kilometers) south of San Francisco, and back to Burbank. Her average speed was 492.34 kilometers per hour (305.93 miles per hour).¹

Jackie Cochran with the Seversky AP-7A, NX1384. Her racing number, 13, has not yet been painted on the fuselage. (San Diego Air and Space Museum Archive)
Jackie Cochran with the Seversky AP-7A, NX1384. Her racing number, 13, has not yet been painted on the fuselage. (San Diego Air and Space Museum Archive)

The Los Angeles Times reported:

Woman Flyer Sets Air Record

Jacqueline Cochran Betters Speed Mark for 1000 Kilometers

     Streaking a path across the hills to the north of Union Air Terminal, a tiny silver pursuit plane yesterday roared a successful climax to Jacqueline Cochran’s bid for a new 1000-kilometer speed record. Her time: 2h. 2m. for an average of 309 m.p.h. to San Mateo and return.

     The slim, brown-eyed pilot, America’s No. 1 woman speed flyer, settled her sleek Seversky on the runway, braked the ship to a stop and pulled off her helmet to loose a flood of tawny hair before the propeller blades stopped turning.

STARTS AFTER LUNCH

     “Whew!” she said. “Has anyone got a cigarette?”

     It was shortly after lunch that Miss Cochran, clad in green slacks and coat, climbed into her 1200-horsepower ship and thundered down the runway to climb in circles to 10,000 feet. Loosing a trail of blue smoke at this altitude she was officially clocked on the course by Larry Therkelson, Southland representative of the National Aeronautic Association, who checker her in again at the same level 2h. and 2m. later.

KEEPS PLANE HIGH

      After entering the course, Miss Cochran said, she nosed her low-wing monoplane upward again, climbing to 15,000 feet. At San Mateo, she dropper to 10,000 feet again to circle a pylon, and climbed back to the higher level for the return race.

     Miss Cochran said she used oxygen almost continuously during the flight.

     It was the second time the comely woman flyer attempted to shatter her own record of 203 m.p.h., her first try last Aug. 26 having gone awry because N.A.A. officials were unable to clock her as she swung above Union Air Terminal at 14,700 feet.

Los Angeles Times, Vol. LVIII, Saturday, 16 September 1939, Page 6, Column 6

Jackie Cochran’s Seversky AP-7, NX1384, at the Union Air Terminal, Burbank, California, September 1939. (Unattributed)

The Seversky AP-7 was an improved civil version of the Seversky P-35 fighter, which was the first U.S. Army Air Corps single engine airplane to feature all-metal construction, an enclosed cockpit and retractable landing gear. It was designed by Major Alexander Nikolaievich Prokofiev de Seversky, a World War I Russian fighter ace.

Cochran’s AP-7A was a specially-built racer, modified from the original AP-7 with a new, thinner, wing and different landing gear arrangement. It was powered by a an air-cooled, supercharged, 1,829.39-cubic-inch-displacement (29.978 liter) Pratt & Whitney Twin Wasp S1B3-G (R-1830-11) two-row 14-cylinder radial engine rated at 850 horsepower at 2,450 r.p.m. at 5,000 feet (1,524 meters), and 1,000 horsepower at 2,600 r.p.m. for take off. The engine turned a three-bladed Hamilton-Standard controllable-pitch propeller 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).

This is the same airplane in which she won the 1938 Bendix Trophy.

Seversky AP-7 NX1384, seen from below. In this early configuration, the landing gear folds rearward. (San Diego Air & Space Museum Archives)

¹ FAI Record File Number 12027

© 2018, Bryan R. Swopes

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