Tag Archives: Boeing Y1B-17

12 May 1938

U.S. Army Air Corps YB-17 Flying Fortresses numbers 80 and 82 fly alongside S.S. Rex, 620 nautical miles east of Sandy Hook, 12 May 1938. (Photograph by Major George W. Goddard, U.S. Army Air Corps)

12 May 1938: Three Boeing B-17 Flying Fortress four-engine heavy bombers of the 49th Bombardment Squadron, 2nd Bombardment Group, departed Mitchel Field, Long Island, New York, in heavy rain and headed eastward over the Atlantic Ocean. Their mission, assigned by Major General Frank M. Andrews, commanding General Headquarters, U.S. Army Air Corps, was to locate and photograph the Italian passenger liner, S.S. Rex, then on a transatlantic voyage to New York City. The purpose was to demonstrate the capabilities and effectiveness of long-range bombers.

Boeing YB-17 Flying Fortress 36-151, 42nd Bombardment Squadron, 2nd Bombardment Group, Number 80, in flight over New York City, 28 March 1937. The Art Deco skyscraper behind the bomber is the Chrysler Building, 1,046 feet (319 meters) tall. (American Air Museum in Britain)

The flight was led by Major Caleb Vance Haynes, commanding officer of the 49th Bombardment Squadron, flying B-17 number 80. The 2nd Bomb Group commanding officer, Lieutenant Colonel Robert Olds, was aboard Haynes’ B-17, along with an NBC radio crew to broadcast news of the interception live across the country. Reporters from the New York Times and the New York Herald Tribune were aboard the other airplanes.

1st Lieutenant Curtis Emerson LeMay, Air Corps, United States Army.

The planning of the interception and in-flight navigation was performed by First Lieutenant Curtis E. LeMay. Position reports from S.S. Rex were obtained and forwarded to LeMay as the aircraft were taxiing for takeoff.

The flight departed Mitchel Field at 8:45 a.m. They encountered heavy rain, hail, high winds and poor visibility, but at 12:23 p.m., the Flying Fortresses broke out of a squall line and the passenger liner was seen directly ahead. They flew alongside the ship at 12:25 p.m., 620 nautical miles (1,148.24 kilometers) east of Sandy Hook, New York. They were exactly on the time calculated by Lieutenant LeMay.

The B-17s made several passes for still and motion picture photography while NBC broadcast the event on radio.

Colonel Olds would rise to the rank of Major General and command 2nd Air Force during World War II. He was the father of legendary fighter pilot Brigadier General Robin Olds. Major Hayes served in various combat commands and retired at the rank of Major General in 1953.

Curtis LeMay would be a major in command of the 305th Bombardment Group, a B-17 unit, at the beginning of World War II. He personally led many combat missions over Europe, and would command the 4th Bombardment Wing, then the 3rd Air Division. By the end of the war, he was in command of XXI Bomber Command based in the Marianas Islands. From 1948 to 1957, General LeMay commanded the Strategic Air Command. He served as Vice Chief of Staff of the Air Force., 1957–1961. General LeMay was Chief of Staff, United States Air Force, from 1961 to 1965.

At the time of the interception of the Rex, there were only 12 B-17s in the Air Corps inventory: the original Y1B-17 service development airplanes. By the end of production in 1945, 12,731 B-17 Flying Fortress bombers had been built by three aircraft manufacturers.

Boeing YB-17 Flying Fortress 36-149. (U.S. Air Force)
Boeing Y1B-17 Flying Fortress 36-149. (U.S. Air Force)

The Boeing B-17 (Model 299B, previously designated Y1B-17, and then YB-17) was a pre-production service test prototype. Thirteen had been ordered by the Air Corps. It 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).

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

The YB-17 was powered by four air-cooled, supercharged 1,823.129-cubic-inch-displacement (29.876 liter) Wright Aeronautical Division Cyclone G59 (R-1820-51) nine-cylinder radial engines with a compression ratio of 6.45:1. The R-1820-51 had a Normal Power rating of 800 horsepower at 2,100 r.p.m. at Sea Level, and 1,000 horsepower at 2,200 r.p.m. for Takeoff, burning 100-octane gasoline. A long carburetor intake on top of the engine nacelles visually distinguishes the YB-17 from the follow-on YB-17A. The engines drove three-bladed Hamilton Standard constant-speed propellers through a 0.6875:1 gear reduction. The R-1820-51 was 3 feet, 9.06 inches (1.145 meters) long and  4 feet, 6.12 inches (1.375 meters) in diameter. It weighed 1,200.50 pounds (544.54 kilograms).

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

The YB-17 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). 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) and the 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 air-cooled Browning .30-caliber machine guns.

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

© 2019, 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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