Tag Archives: Wright Aeronautical Corporation

9 May 1926

The Byrd Arctic Expedition Fokker F.VIIa/3m at Spitzbergen, Svalbard, 9 May 1927. (Ohio State University Archives)

9 May 1926: Lieutenant Commander Richard Evelyn Byrd, Jr., and Chief Aviation Pilot Floyd Bennett, United States Navy, departed Spitzbergen in the Svalbard Archipelago, Norway, on a round-trip flight to the North Pole.

Lieutenant Commander Richard E. Byrd, Jr., U.S. Navy
Lieutenant Commander Richard E. Byrd, Jr., U.S. Navy (Library of Congress)
Chief Aviation Pilot Floyd Bennett, U.S. Navy (Photo NH 50611)
Chief Aviation Pilot Floyd Bennett, U.S. Navy, circa April 1925 (U.S. Navy)

Their aircraft was a Fokker F.VIIa/3m three-engine, high-wing monoplane, construction number 600. The airplane was It was purchased for the Byrd Arctic Expedition by Edsel Ford, and named Josephine Ford in honor of his 3-year-old daughter, Josephine Clay Ford.

Fokker F.VIIa/3m c/n 4900, Josephine Ford. (Getty Images/Hulton Archive)
Fokker F.VIIa/3m, Josephine Ford. (Getty Images/Hulton Archive)

With Chief Bennett as the expedition’s pilot and Lieutenant Commander Byrd navigating, they flew approximately 840 miles (1,350 kilometers) to the Pole and returned the same day. The total duration of the flight was 15 hours, 44 minutes.

Commander Byrd, President Coolidge, Warrant Officer Bennett.
Secretary of the Navy Curtis Dwight Wilbur, Commander Richard Evelyn Byrd, Jr., President John Calvin Coolidge, Jr., Warrant Officer Floyd Bennett and Admiral Edward Walter Eberle, at the White House, 5 March 1927.
Medal of Honor, U.S. Navy, 1919–1942.

For this accomplishment, Lieutenant Commander Byrd was promoted to Commander, and Chief Bennett to Warrant Officer. Both aviators were awarded the Medal of Honor by President Coolidge.

In the years since this event, there has been speculation that the airplane may not have actually reached the North Pole. Professor Gerald Newsom of Ohio State University, an astronomer who taught celestial navigation, analyzed Byrd’s handwritten notes and estimated that because of the inadequacies of the equipment then available to Byrd, Josephine Ford may have flown 21 miles (33.8 kilometers) beyond the North Pole, or fallen 78 miles (125.5 kilometers) short. Professor Newsom pointed out, though, that the fact the Byrd was able to return to Svalbard after nearly 16 hours proves that he knew how to navigate using that equipment under those conditions.

(See https://web.archive.org/web/20161216185546/http://researchnews.osu.edu/archive/byrdnorth.htm for additional information.)

Richard E. Byrd holding a Bumstead Sun Compass used for celestial navigation at very high latitudes, 1925. (Maynard Owen Williams/National Geographic Society, Image ID 612617)
Richard E. Byrd holding a Bumstead Sun Compass used for celestial navigation at very high latitudes, 1925. (Maynard Owen Williams/National Geographic Society, Image ID 612617)
Fokker F.VIIa/3m c/n 4900, Josephine Ford (David Horn Collection)
Fokker F.VIIa/3 Josephine Ford (David Horn Collection)
Prototype Fokker F.VIIa/3m, c/n 600, at Detroit Michigan, September 1925. (Robert McMahan Collection)

Josephine Ford is the first Fokker F.VIIa/3m monoplane, c/n 600. It was built by Anton H.G. Fokker’s N.V. Koninklijke Nederlandse Vliegtuigenfabriek Fokker at Veere, Netherlands in 1925, and made its first flight at Schipol, 4 September 1925. It was demonstrated for Koninklijke Luchtvaart Maatschappij N.V. (KLM, Royal Dutch Airlines), then disassembled and shipped to the United States. 600 was flown from New York to Detroit, where it participated in the First Annual Aerial Reliability Tour, 28 September–3 October 1925, flown by Egbert P. Lott. The airplane was evaluated by the U.S. Army Air Corps at Wright Field, and was then sold to Edsel Ford.

The United States did not register aircraft prior to 1927. According to the Federal Aviation Administration’s Registry data base, FOKKER VII (TRI-MOTOR) Serial Number 600 was registered 21 June 1927 to the Ford Motor Company, Dearborn, Michigan, as NC267. The registration was cancelled 14 March 1930.

Fokker F.VII 3m Josephine Ford (Fokker Aircraft)

Sources vary as to the actual dimensions of the Fokker F.VIIa/3m. The Henry Ford, the museum which owns the airplane, gives its dimensions as 49.167 feet (14.986 meters) in length, with a wingspan of 63.5 feet (19.355 meters) and height of 12.75 feet (3.886 meters). Another source says that the airplane is 47 feet, 11 inches (14.605 meters) long with a wingspan of 63 feet, 4 inches (19.304 meters) and height of 12 feet, 8 inches (3.861 meters). Its empty weight is variously given as 4,630 pounds, 5,060 pounds or 6,724 pounds and maximum takeoff weight is 7,950 pounds, 8,800 pounds or 11,464 pounds. It has a cruise speed of 81 knots. Or 90. . . .

Josephine Ford was powered by three air-cooled 787¼-cubic-inch-displacement (12.901 liter) Wright Aeronautical Corporation Model J-4 Whirlwind nine-cylinder radial engines, rated at 215 horsepower at 1,800 r.p.m. The J-4 weighed 475 pounds. (The specific variant, J-4, J-4A, or J-4B, is not known.)

Josephine Ford is in the collection of The Henry Ford Museum, Dearborn, Michigan.

Fokker F.VII/3m Josephine Ford, flown by the Byrd Arctic Expedition, in the collection of The Henry Ford Museum.
Fokker F.VIIa/3m Josephine Ford, flown by the Byrd Arctic Expedition, in the collection of The Henry Ford, Dearborn, Michigan. (The Henry Ford Museum)

© 2019, Bryan R. Swopes

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8 April 1931

Amelia Earhart with Pitcairn Autogiro Co. PCA-2 #4, X760W, at Pitcairn Field, Warrington, Pennsylvania, 8 April 1931. (Purdue University)
Amelia Earhart with Pitcairn Autogiro Co. PCA-2 #4, NX760W, at Pitcairn Field, Warrington, Pennsylvania, 8 April 1931. (Purdue University)

8 April 1931: Amelia Earhart, flying a Pitcairn PCA-2 autogyro, reached an altitude of 18,415 feet (5,613 meters) ¹ over Warrington, Pennsylvania. The duration of the flight, her second of the day, was 1 hour, 49 minutes. She landed at 6:04 p.m.

A sealed barograph was carried aboard to record the altitude for an official record. Following the flight, the barograph was sent to the National Aeronautic Association headquarters in Washington, D.C., for certification.

08 Apr 1931, Pennsylvania, USA --- Original caption: Miss Amelia Earhart in two altitude tests with an autogiro plane, at the Pitcairn Airfield, Willow Grove, Pa., soars to height of 18,500 feet in the first, and surpasses that mark by 500 feet in the second. If her barographs correspond with those marks, she in all probability will have established a world record for men as well as women. She is the only woman who ever piloted one of the "windmill" types of craft. Photo shows Amelia Earhart handing Major Luke Christopher, her barograph after her first flight. --- Image by © Bettmann/CORBIS
Amelia Earhart, in the cockpit of a Pitcairn PCA-2 autogyro, handing a barograph to Major Luke Christopher, National Aeronautic Association. (© Bettmann/CORBIS)

An autogyro is a rotary wing aircraft that derives lift from a turning rotor system which is driven by air flow (autorotation). Unlike a helicopter, thrust is provided by an engine-driven propeller. The engine does not drive the rotor.

The Pitcairn Autogyro Company’s PCA-2 was the first autogyro certified in the United States. Operated by a single pilot, it could carry two passengers. The fuselage was constructed of welded steel tubing, covered with doped fabric and aluminum sheet.

Amelia Earhart with the Pitcairn PCA-2 aurtogyro, NX760W.
Amelia Earhart with a Pitcairn PCA-2 autogyro.

The PCA-2 was 23 feet, 1 inch (7.036 meters) long, excluding the rotor. The low-mounted wing had a span of 30 feet, 0 inches (9.144 meters), and the horizontal stabilizer and elevators had a span of 11 feet, 0 inches. (3.353 meters). The overall height of the autogyro was 13 feet, 7 inches (4.140 meters). The PCA-2 had an empty weight of 2,233 pounds (1,013 kilograms) and gross weight of 3,000 pounds (1,361 kilograms).

The four-bladed rotor was semi-articulated with horizontal and vertical hinges to allow for blade flapping and the lead-lag effects of Coriolis force. Unlike the main rotor of a helicopter, there was no cyclic- or collective-pitch motion. The rotor system was mounted at the top of a pylon and rotated counter-clockwise, as seen from above. (The advancing blade is on the right.) The rotor had a diameter of 45 feet, 0 inches (13.716 meters). The blades were approximately 22 feet (6.7 meters) long, with a maximum chord of 1 foot, 10 inches (0.559 meters). Each blade was constructed with a tubular steel spar with mahogany/birch plywood ribs, a formed plywood leading edge and a stainless steel sheet trailing edge. They were covered with a layer of very thin plywood. A steel cable joined the blades to limit their lead-lag travel.

The aircraft was powered by an air-cooled, supercharged, 971.930-cubic-inch-displacement (15.927 liter) Wright R-975E Whirlwind 330 nine-cylinder radial engine with a compression ratio of 5.1:1. The R-975E produced a maximum 330 horsepower at 2,000 r.p.m. at Sea Level, burning 73-octane gasoline. The engine turned a two-bladed Hamilton Standard variable-pitch propeller through direct drive. The engine weighed 635 pounds (288 kilograms).

The PCA-2 had two fuel tanks with a total capacity of 52 gallons (197 liters). It also had a 6½ gallon (24.6 liter) oil tank to supply the radial engine.

The PCA-2 had a maximum speed of 120 miles per hour (193 kilometers per hour). It had a service ceiling of 15,000 feet (4,572 meters) and a range of 290 miles (467 kilometers).

Pitcairn Autogyro Co. PCA-2 NX760W at East Boston Airport, October 1930. (Courtesy of the Boston Public Library, Leslie Jones Collection.)
Pitcairn Autogyro Co. PCA-2 NX760W at East Boston Airport, October 1930. (Courtesy of the Boston Public Library, Leslie Jones Collection.)

¹ Most sources state that Earhart set a “world altitude record” on this flight. TDiA checked with the National Aeronautic Association, which certifies aviation records in the United States. NAA has no such record in its files. Fédération Aéronautique Internationale (FAI) records show that Earhart set three world speed records in 1930, and a world distance record in 1932. She is not credited with an altitude record, or any flight record in an autogyro.

© 2019, Bryan R. Swopes

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18 March 1939

Boeing Model 307 Stratoliner NX19901 taking of at Boeing Field, Seattle, Washington. (San Diego Air & Space Museum Archives)

18 March 1939: At 12:57 p.m., Pacific Standard Time (19:47 G.M.T.), the Boeing Model S-307 Stratoliner, NX19901, took off from Boeing Field, Seattle, Washington, on Test Flight No. 19. Julius Augustus Barr was the pilot in command.

The S-307, Boeing serial number 1994, was a prototype four-engine, pressurized commercial airliner. It had first flown on 31 December 1938, with Boeing’s Chief of Flight Test, Edmund Turney (“Eddie”) Allen, as first pilot (the Pilot in Command), and Julius Barr as his copilot. Allen had flown the first eighteen flights. “The performance of aircraft NX 19901 on flights prior to Test Flight No. 19 had either met or exceeded the manufacturer’s estimates.”

Julius Barr was employed by Boeing as a test pilot, 16 November 1938. Following Flight Test No. 15, Allen approved Barr to act as first pilot on the Model 307. He first served as the pilot in command of NX19901 on 21 January 1939. This was a taxi test, with the Stratoliner never leaving the ground. Barr first flew the airplane nearly two months later, 16 March 1939, with copilot Earl Alvin Ferguson. Barr made two more flights on 17 March. Harlan Hull, Chief Pilot of Transcontinental and Western Air, Inc., flew as copilot.

At takeoff on 18 March 1939, Barr had only 2 hours, 6 minutes as pilot in command of the Boeing 307; and 17 hours, 55 minutes as second in command. He had flown as an observer aboard NX19901 for 1 hour, 52 minutes.

There were ten persons on board the Stratoliner for Test Flight No. 19. In addition to Julius Barr as P.I.C., the designated copilot was Earl Ferguson. There were two alternate copilots, Harlan Hull and Benjamin J. Pearson, an assistant sales manager for Boeing. Ralph LaVenture Cram was first aerodynamcist, assisted by John Kylstra. William C. Doyle served as oscillograph operator, and Harry T. West, Jr., was the engineering officer. These were all Boeing employees. Pieter Guillonard, technical director of Koninklijke Luchtvaart Maatschappij N.V. (KLM Royal Dutch Airlines), acted as recorder and photographer, while Albert Gillis von Baumhauer, an engineer with the Luchtvaartdienst (the Dutch Aviation Authority), acted as an assistant aerodynamicist.

Albert G. von Baumhauer

Specialized test equipment had been installed at the copilot’s position. For this reason, Von Baumhauer, rather than the designated copilot, Ferguson, was in the copilot’s seat during this test flight. (Von Baumgartner held a Dutch private pilot certificate, issued 28 November 1931. Since that time, he had flown only 116 hours, and had no experience flying multi-engine aircraft. He was not qualified to act as copilot.)

Guillonard and Von Baumhauer had recommended a series of tests to be conducted on Test Flight No. 19, including observing the airplane’s behavior following an engine cut on takeoff with no rudder input; a series of side slips and stall tests. Von Baumhauer had emphasized “complete stalls” rather than initiating recovery when stall was detected.

After takeoff, NX19901 climbed to 10,000 feet (3,048 meters) and at 140 miles per hour (225 kilometers per hour) a series of static longitudinal stability tests were performed. According to the test flight plan, side slips were to be investigated next.

Boeing 307 Stratoliner NX19901 with both propellers on right wing feathered. Note the rudder deflection. (Boeing)

     “At 1:12 P.M. (PST) a radio message was transmitted from NX 19901 to the Boeing Aircraft Company radio station located at Seattle, Washington, which message gave the position of the aircraft as being between Tacoma Washington and Mount Rainier at an altitude of 11,000 feet. Some two or three minutes later, while flying at a comparatively slow rate of speed in the vicinity of Alder, Washington, the aircraft stalled and began to spin in a nose down attitude. After completing two or three turns in the spin, during which power was applied, it recovered from the spin and began to dive. The aircraft partially recovered from the dive at an altitude of approximately 3,000 feet above sea level, during which recovery it began to disintegrate. Outboard sections of the left and right wings failed upward and broke entirely loose from the aircraft. Major portions of the vertical fin and portions of the rudder were carried away by wing wreckage. The outboard section of the left elevator separated from the stabilizer and both fell to the ground detached. The right horizontal tail surface, being held on by the fairing long the top surface and also by the elevator trim tab cables, remained with the fuselage. The No. 1 engine nacelle also broke loose from the aircraft and fell to the ground separately. The main body of the aircraft settled vertically and struck the ground in an almost level attitude both longitudinally and laterally at a point approximately 1,200 feet above sea level. Watches and clocks aboard the aircraft, which were broken by the force of the impact, indicated the time of the accident at approximately 1:17 p.m. (PST).”

AIR SAFETY BOARD REPORT, at Pages 34–35.

Diagram of probable flight path of NX19901 from Air Safety Board report.

All ten persons aboard were killed in the crash. The Stratoliner was destroyed. Because of the water ballast in the main fuel tanks, there was no post crash fire.

Wreckage of Boeing Model 307 Stratoliner NX19901, right rear quarter.
Wreckage of Boeing Model 307 Stratoliner NX19901, right front quarter.
Wreckage of Boeing Model 307 Stratoliner NX19901 near Alder, Washington
Wreckage of Boeing Model 307 Stratoliner NX19901 near Alder, Washington. (SDASM)
Wreckage of Boeing Model 307 Stratoliner NX19901, left front quarter.

During the crash investigation it was found that two B-17s had previously been spun. The first,

“. . . while flying with a gross load of about 42,000 pounds at an altitude of 14,000 feet, went into an inadvertent spin and made two complete turns before recovery was effected. During the pull-out from the ensuing dive, permanent distortion occurred in the structure of both wings, necessitating the installation of new wings on the aircraft.

     “In the second of these experiences, a similar ship was intentionally permitted to enter a spin following a complete stall. The controls were immediately reversed and the aircraft responded promptly, enabling the pilot to effect recovery after three-fourths of a turn in—

     “Evidence indicated that power was used in recovery from the spin in the case of NX 19901. It should be noted that in the two instances above described recovery from spin in similar aircraft was accomplished without the employment of power. In one of these cases, permanent distortion occurred in both wings.”

AIR SAFETY BOARD REPORT, at Pages 48 and 49.

Diagram of wing failure under load. (Air Safety Board Report)

PROBABLE CAUSE

     “Structural failure of the wings and horizontal tail surfaces due to the imposition of loads thereon in excess of those for which they were designed, the failure occurring in an abrupt pull-out from a dive following recovery from an inadvertent spin.”

Crash site diagram. (Air Safety Board Report)
Boeing Model 307 Stratoliner NX19901. The engine cowlings have been removed. The inboard right engine is running. The arrangement of passenger windows differs on the right and left side of the fuselage. (San Diego Air & Space Museum Archives)

The Boeing Model 307 was operated by a crew of five and could carry up to 33 passengers.  It was the first pressurized airliner and, because of its complexity, it was also the first airplane to include a flight engineer as a crew member. It could maintain a cabin pressure equivalent to 12,000 feet (3,650 meters) to a pressure altitude of 19,000 feet (5,791 meters).

The Model 307 used the wings, tail surfaces, engines and landing gear of the production B-17B Flying Fortress heavy bomber. The vertical fin and rudder were of the same design as the B-17B’s, though somewhat larger. The fuselage was circular in cross section to allow for pressurization. It was 74 feet, 4 inches (22.657 meters) long with a wingspan of 107 feet, 3 inches (32.690 meters) and overall height of 20 feet, 9½ inches (6.337 meters). The wings had 4½° dihedral and 3½° angle of incidence. The empty weight was 29,900 pounds (13,562.4 kilograms) and loaded weight was 45,000 pounds (20,411.7 kilograms).

The airliner was powered by four air-cooled, geared and supercharged, 1,823.129-cubic-inch-displacement (29.875 liter) Wright Cyclone 9 GR-1820-G102 9-cylinder radial engines with a compression ratio of 6.7:1, rated at 900 horsepower at 2,200 r.p.m., and 1,100 horsepower at 2,200 r.p.m. for takeoff. These drove three-bladed Hamilton-Standard Hydromatic propellers through a 0.6875:1 gear reduction in order to match the engine’s effective power range with the propellers. The GR-1820-G102 was 4 feet, 0.12 inches (1.222 meters) long, 4 feet, 7.10 inches (1.400 meters) in diameter, and weighed 1,275 pounds (578 kilograms).

The maximum speed of the Model 307 was 241 miles per hour (388 kilometers per hour) at 6,000 feet (1,828.8 meters). Cruise speed was 215 miles per hour (346 kilometers per hour) at 10,000 feet (3,048 meters). The service ceiling was 23,300 feet (7,101.8 meters).

Boeing Model 307 Stratoliner NX19901 with all engines running. (San Diego Air & Space Museum Archives)

Julius Augustus Barr was born at Normal, Illinois, 6 December 1905. He was the son of Oren Augustus Barr, a teacher and school superintendent, and Margaret M. Wallace Barr. He grew up in Pittsburg, Kansas. He attended the Kansas State Teachers College at Pittsburg in 1925. He was a member of the Alpha Gamma Tau (ΑΓΤ) fraternity, of which he was the treasurer.

Julius Augustus Barr

Barr enlisted in the Air Corps, United States Army, and was trained as a pilot at Brooks and Kelly Fields, San Antonio, Texas.

On 1 July 1928, Julius Barr married Miss Effie Hortense Roberson at Pittsburg, Kansas. They would have two children, Jo Anne Barr, and Gene Edward Barr.

In 1930, Barr and his family lived in Cheyenne, Wyoming. He flew as an air mail pilot, and was employed by Boeing Air Transport.

During the mid 1930s, the Barr family traveled to China, where he acted as manager of the airport at Hankow, and conducted flight training. He then flew as the personal pilot of Zhang Xueliang (also known as Chang Hseuh-Liang), (“The Young Marshal”). Zhang and another of other communist generals arrested Chiang Kai-Shek in the Xi’an Incident, December 1936. Chiang was released after two weeks, and Zhang placed under house arrest for the remainder of his life. (The others were executed.) Julius Barr then served as the personal pilot for Soong Mei-ling (“Madame Chiang”), and helped General Chang with the air defense of Shanghai during the Second Sino-Japanese War.

Barr and his family departed Hong Kong aboard S.S. Empress of Russia, which arrived at Victoria, British Columbia, Canada, 14 November 1938. He then went to work as a test pilot for Boeing two days later.

Julius Barr had flown a total of approximately 5,000 hours. Of these, 2,030 hours were in single-engine airplanes, 2,240 hours in twin-engine, and 765 hours in 3 engine.

Julius Augustus Barr was buried at the Mount Olive Cemetery, Pittsburg, Kansas.

© 2019, Bryan R. Swopes

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31 December 1938

Boeing Model 307 Stratoliner with all engines running, Boeing Field, Seattle, Washington, circa 1939. (San Diego Air & Space Museum Archives)

31 December 1938: Boeing Model 307 Stratoliner NX19901 made its first flight at Boeing Field, Seattle, Washington. The test pilot was Eddie Allen, with co-pilot Julius A. Barr.

The Model 307 was a four-engine commercial airliner that used the wings, tail surfaces, engines and landing gear of the production B-17B Flying Fortress heavy bomber. The fuselage was circular in cross section to allow for pressurization. It was the first pressurized airliner and because of its complexity, it was also the first airplane to include a flight engineer as a crew member.

Boeing 307 Stratoliner NX19901 with both propellers on right wing feathered. (Boeing)
Boeing 307 Stratoliner NX19901 with both propellers on right wing feathered. (Boeing)

The Associated Press news agency reported:

Test Of Big Craft Begins

     SEATTLE, Dec. 31—(AP)—The world’s first plane, designed for flying in the sub-stratosphere, the new Boeing “Stratoliner”, performed “admirably” in a 42-minute first test flight in the rain today.

     The big ship, with a wingspread of 107 feet, three inches, climbed to 4,000 feet, the ceiling, and cruised between here, Tacoma and Everett. Speed was held down to 175 miles an hour.

     “The control and stability and the way it handled were very nice,” Edmund T. Allen, pilot, said. “She performed admirably.”

     The 33-passenger ship was built to fly at altitudes of 20,000 feet.

     No more tests are planned until next week. The supercharging equipment for high altitude flights will be installed later.

Arizona Republic, Vol. IL, No. 228, Sunday, 1 January 1939, Page 2, Column 4

Boeing Model 307 Stratoliner NX19901 taking of at Boeing Field, Seattle, Washington. (San Diego Air & Space Museum Archives)

On March 18, 1939, during its 19th test flight, the Stratoliner went into a spin, then a dive. It suffered structural failure of the wings and horizontal stabilizer when the flight crew attempted to recover. NX19901 was destroyed and all ten persons aboard were killed.

Boeing Model 307 Stratoliner NX19901. (San Diego Air and Space Museum Archive, Catalog # 01 00091288)
Boeing Model 307 Stratoliner NX19901. The engine cowlings have been removed. The inboard right engine is running. The arrangement of passenger windows differs on the right and left side of the fuselage. (San Diego Air & Space Museum Archives)

The Boeing Model 307 was operated by a crew of five and could carry 33 passengers. It was 74 feet, 4 inches (22.657 meters) long with a wingspan of 107 feet, 3 inches (32.690 meters) and overall height of 20 feet, 9½ inches (6.337 meters). The wings had 4½° dihedral and 3½° angle of incidence. The empty weight was 29,900 pounds (13,562.4 kilograms) and loaded weight was 45,000 pounds (20,411.7 kilograms).

The airliner was powered by four air-cooled, geared and supercharged, 1,823.129-cubic-inch-displacement (29.875 liter) Wright Cyclone 9 GR-1820-G102 9-cylinder radial engines with a compression ratio of 6.7:1, rated at 900 horsepower at 2,200 r.p.m., and 1,100 horsepower at 2,200 r.p.m. for takeoff. These drove three-bladed Hamilton-Standard Hydromatic propellers through a 0.6875:1 gear reduction in order to match the engine’s effective power range with the propellers. The GR-1820-G102 was 4 feet, 0.12 inches (1.222 meters) long, 4 feet, 7.10 inches (1.400 meters) in diameter, and weighed 1,275 pounds (578 kilograms).

Boeing Model 307 Stratoliner NX19901. (San Diego Air & Space Museum Archives)

The maximum speed of the Model 307 was 241 miles per hour (388 kilometers per hour) at 6,000 feet (1,828.8 meters). Cruise speed was 215 miles per hour (346 kilometers per hour) at 10,000 feet (3,048 meters). The service ceiling was 23,300 feet (7,101.8 meters).

Boeing Model 307 Stratoliner NX19901 with all engines running. (San Diego Air and Space Museum Archive, Catalog # 01 00091291)
Boeing Model 307 Stratoliner NX19901 with all engines running. (San Diego Air & Space Museum Archives)
A Transcontinental and Western Airlines (TWA) Boeing 307 Stratoliner with cabin attendants. (TWA)
A Transcontinental and Western Airlines (TWA) Boeing 307 Stratoliner with cabin attendants. (Trans World Airlines)

During World War II, TWA sold its Stratoliners to the United States government which designated them C-75 and placed them in transatlantic passenger service. After the war, the 307s were returned to TWA and they were sent back to Boeing for modification and overhaul. The wings, engines and tail surfaces were replaced with those from the more advanced B-17G Flying Fortress.

Boeing C-75 Stratoliner. (San Diego Air and Space Museum Archive, Catalog # 01 00091316)
Boeing C-75 Stratoliner “Comanche,” U.S. Army Air Corps serial number 42-88624, formerly TWA’s NC19905. (San Diego Air & Space Museum Archives)

Of the ten Stratoliners built for Pan Am and TWA, only one remains. Fully restored by Boeing, NC19903 is at the Stephen F. Udvar-Hazy Center of the Smithsonian Institution.

The only existing Boeing Model 307 Stratoliner, NC19903, Clipper Flying Cloud, at the Smithsonian Institution National Air and Space Museum, Steven F. Udvar-Hazy Center. (Photo by Dane Penland, National Air and Space Museum, Smithsonian Institution)
The only existing Boeing Model 307 Stratoliner, NC19903, Clipper Flying Cloud, at the Smithsonian Institution National Air and Space Museum, Steven F. Udvar-Hazy Center. (Photo by Dane Penland, National Air and Space Museum, Smithsonian Institution)
Boeing Model 307 Stratoliner NX19903 after upgrade, circa 1945. (Boeing)

© 2018, Bryan R. Swopes

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2 December 1936

Boeing YB-17 Flying Fortress 36-149. (U.S. Air Force)
Boeing YB-17 Flying Fortress 36-149. (U.S. Air Force)

2 December 1936: The first Boeing YB-17, U.S. Army Air Corps serial number 36-149, made its first flight.

Although the prototype Boeing Model 299, NX13372, had crashed at Wright Field, Ohio, 30 October 1935, the Army had ordered thirteen Y1B-17 service test aircraft, serials 36-149–36-161. Prior to the model’s first flight, this designation was changed to YB-17. (The “-1-” in the original Y1B-17 designation indicated that the service test bombers were ordered using funding other than the normal appropriations for new aircraft.)

Boeing YB-17. (U.S. Air Force)
Boeing YB-17 36-149. (U.S. Air Force)

The YB-17 had several improvements over the Model 299, which was retroactively designated XB-17. There was a long carburetor intake on top of the engine nacelles which visually distinguishes the YB-17 from the follow-on YB-17A. The main landing gear has one strut rather than the two of the Model 299.

Boeing YB-17 36-149. (U.S. Air Force)

The Boeing Model 299B, designated YB-17 by the Army Air Corps, was 68 feet, 4 inches (20.828 meters) long with a wingspan of 103 feet, 9 inches (31.633 meters) and the overall height was 18 feet, 4 inches (5.588 meters). It had an empty weight of 24,465 pounds (11,097 kilograms), gross weight of 34,880 pounds (15,821 kilograms) and maximum takeoff weight of 42,600 pounds (19,323 kilograms).

Boeing YB-17 36-149. (U.S. Air Force)

Instead of the Pratt & Whitney engines installed on the 299, the YB-17 had four air-cooled, supercharged 1,823.129-cubic-inch-displacement (29.876 liter) Wright Aeronautical Division Cyclone 9 R-1820G5 (R-1820-39) nine-cylinder radial engines with a compression ratio of 6.45:1. They turned three-bladed Hamilton Standard constant-speed propellers through a 16:11 gear reduction drive, in order to match the engines’ effective power range with the propellers. The R-1820-39 was rated at 805 horsepower at 2,100 r.p.m., at Sea Level, and 930 horsepower at 2,200 r.p.m. for takeoff. The R-1820-39 was 45-7/16 inches (1.154 meters) long and 54¼ inches (1.378 meters) in diameter, and weighed 1,198 pounds (543.4 kilograms).

The cruise speed of the YB-17 was 217 miles per hour (349 kilometers per hour) and the maximum speed was 256 miles per hour (412 kilometers per hour) at 14,000 feet (4,267 meters). Its service ceiling was 30,600 feet (9,327 meters). The bomber’s maximum range was 3,320 miles (5,343 kilometers).

The YB-17 could carry 8,000 pounds (3,629 kilograms) of bombs. Defensive armament consisted of five .30-caliber air-cooled Browning machine guns.

Boeing YB-17 36-149 nosed over on landing at Seattle, 7 December 1936. (Unattributed)

36-149 was damaged in a landing accident 7 December 1936. It was repaired and then flown to Wright Field, Dayton, Ohio, 11 January 1937. After testing at Wright Field, 36-149 was delivered to the 2nd Bombardment Group, Langley Field, Virginia. By 1938 the bomber was back at Wright Field for additional tests.

“In the summer of 1938, Bill [Captain William C. Bentley, Jr., U.S. Army Air Corps, a B-17 test pilot at Langley Field] and his aircrew flew back to Seattle to pick up an additional aircraft, YB-17 tail number 36-149 from Boeing. This aircraft was different from the original thirteen. During its assembly phase at Boeing, it was packed with additional instruments for recording purposes. Once delivered to Langley, the plane was going to be subjected to a variety of stress tests in order to determine how much damage the plane could take and still operate. During its flight to Langley, Bill arrived over the field in a thunderstorm. The strength of the storm flipped the plane upside down, a stress never envisioned by the designers for such a large aircraft, much less one loaded to capacity with measuring instrumentation and a full crew. Using his fighter pilot training, Bill flew the aircraft at its maximum altitude then performed a slow roll to bring the airplane into its proper attitude. After recovering from a harrowing spin, Bill got control of the plane and landed successfully.

“Much to the crew’s amazement, the wings were slightly bent and some rivets were missing. But the measuring instrumentation had recorded all of the stress placed on the plane. . . .”

—The Touch of Greatness: Colonel William C. Bentley, Jr., USAAC/USAF, by Stewart W. Bentley, Jr., Ph.D., AuthorHouse, Bloomington, Indiana, 2010, Chapter 2 at Page 45.

(This meant that a fourteenth YB-17, which had been built specifically as a static test article, could be completed as a Y1B-17A, 37-369.)

Boeing YB-17 at Hamilton Field, California. (U.S. Air Force)

In October 1940 36-149 was transferred to the 19th Bombardment Group at March Field, California. Finally, on 11 February 1942, it was transferred to the Air Park at Amarillo Army Air Field, a B-17 training base in Texas. It was written off 11 December 1942.

After several years of testing, the YB-17 went into production as the B-17 Flying Fortress. By the end of World War II, 12,731 B-17s had been built by Boeing, Douglas and Lockheed Vega.

Boeing YB-17 36-139 arrives at Langley Field, Virginia, 1 March 1937. (U.S. Air Force)
Boeing YB-17 36-139 arrives at Langley Field, Virginia, 1 March 1937. (U.S. Air Force)
Boeing YB-17 36-149 at Langley Field, Virginia, 1 March 1937. (U.S. Air Force)
Boeing YB-17 36-149 at the Golden Gate International Exposition, Treasure Island, California, ca. 1939. (Stephen Fisher)

© 2018, Bryan R. Swopes

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