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BOEING B-17 FLYING FORTRESS
Variants - YB-17 (Y1B-17)

Though still enthusiastic about the Boeing design, the Army Air Corps decided to cut its order for service test YB-17s from 65 to 13 after the crash of the original Model 299. On November 20, 1936, the Army Air Corps changed the source of funding from normal funding to "F-1" procurement, and redesignated the plane Y1B-17 before it even flew.

YB-17 Flying Fortress
Boeing YB-17 Flying Fortress/36-149.
[Source: USAF Photo]

Unlike its predecessor, which had used Pratt & Whitney R-1690 Hornet radial engines, the Y1B-17 used the Wright R-1820 Cyclone that would become standard on the B-17. Several changes were made in the armament and the crew was reduced from seven to six. Most changes were minor: the most notable was switching from double-wishbone to single-arm landing gear.

On December 7, 1936, five days after the first flight of the Y1B-17, the brakes on the aircraft fused during landing, and it nosed over. Though damage was minimal, the cumulative impact of this event and the crash of the Model 299 triggered a Congressional investigation. After the crash the Army Air Corps was put in notice: another crash would mean the end of the program.

YB-17 Flying Fortress
Boeing YB-17 Flying Fortress/36-149 after nosing over during landing on December 7, 1936.
[Source: USAF Photo]

Though they were meant for testing, the commander of Army General Headquarters (Air Force), Major General Frank Andrews, decided to assign twelve Y1B-17s to the 2nd Bomb Group at Langley Field, Virginia. Andrews reasoned that it was best to develop heavy bombing techniques as quickly as possible. Of the thirteen built, one was used for stress testing.

In 1937, the twelve Y1B-17s with the 2nd Bombardment Group at Langley Field represented the entire American fleet of heavy bombers. Most of the time spent with the planes entailed eliminating problems with the aircraft. The most important development was the use of a checklist, to be reviewed by the pilot and copilot before takeoff. It was hoped that this system would prevent accidents similar to that which led to the loss of the 299.

In May 1938, the Y1B-17s (now redesignated B-17) of the 2nd Bombardment Group, led by the lead plane's navigator Curtis LeMay, took part in a demonstration in which they intercepted the Italian liner Rex. Coming into contact with the liner while it was still 610 mi (982 km) out at sea, the demonstration was meant to prove the range and navigational superiority of the B-17. It also showed that the bomber would be an effective tool for attacking an invasion force before it could reach the United States. The Navy was furious about Army intrusion into their mission, and forced the War Department to issue an order restricting the Army Air Corps from operating more than a hundred miles from the American coast.

YB-17 Flying Fortress
Boeing YB-17 Flying Fortress with camouflaged paint scheme,
assigned to the 20th BS/2nd BG, based at Langley Field, VA.
[Source: USAF Photo]

After three years of flight, no serious incidents occurred with the B-17s. In October 1940, they were transferred to the 19th Bombardment Group at March Field.

First Flight: December 2, 1936
Produced: 13

Sources:
Wikipedia
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