The Y1B-17 was the initial service test version of the B-17, thirteen of which had been ordered on January 17, 1936. It was assigned the company designation of Model 299B. It had initially been designated YB-17, but this was changed to Y1B-17 on November 20, 1936, indicating procurement from "F-1" funds rather than from regular appropriations. This change was the source of much confusion for historians, since references were made to both YB-17 and Y1B-17 in the documentation of the day, giving the erroneous perception that there were two series of service-test Boeing Fortresses rather than just one.
The Y1B-17 was basically similar to the Model 299, but had four Wright GR-1830-39 (G2) Cyclone radials in place of the Pratt & Whitney Hornet radials of the Model 299 prototype. The Cyclone was to remain the standard powerplant all throughout the long production run of the Fortress. The crew was reduced to six, and minor changes were made in armament details and in the undercarriage. Perhaps the most readily-noticeable difference was in the the main landing gear, which now had only one leg rather than two. A long carburetor intake on top of the engine nacelles distinguished the Y1B-17 from later models.
The first Y1B-17 (36-149) flew on December 2, 1936. Five days later, the brakes of this aircraft fused and seized up during a landing, and the aircraft nosed over. Although the damage to the aircraft was not severe, the episode was very embarrassing to the Air Corps and a Congressional inquiry was ordered, with angry Congressmen threatening to have the whole program shut down. However, nothing came of this threat except perhaps the fear that if another incident should occur, the entire Army Air Corps heavy bomber program would be cancelled.
All Y1B-17s were delivered between January 11 and August 4, 1937. Twelve of the Y1B-17s were delivered to the 2nd Bombardment Group based at Langley Field, Virginia for evaluation. A thirteenth Y1B-17 was delivered to Wright Field for experimental tests. At this time, the dozen Y1B-17s of the 2nd Bombardment Group comprised the entire heavy bombardment strength of the United States.
The 2nd Bombardment Group spent its time working out the bugs in the B-17. One of the recommendations that they came up with at an early stage was the use of a check list that the pilot and copilot would go through together before takeoff, hopefully preventing accidents such as the one which resulted in the loss of the Model 299.
In early 1938, Colonel Robert C. Olds, commander of the 2nd Bombardment Group flew a Y1B-17 to set a new east-to-west transcontinental record of 12 hours 50 minutes. He immediately turned around and broke the west-to-east record, averaging 245 mph in 10 hours 46 minutes.
Six planes of the 2nd Bombardment group took part in a good will flight from Langley to Buenos Aires, Argentina, taking off from Langley on February 15, 1938 and returning on February 27. They covered a total of 12,000 miles without serious incident.
In May of 1938, planes of the Langley-based 2nd Bombardment Group took part in a demonstration in which they "intercepted" the Italian liner *Rex* while it was still 700 miles out to sea. This was meant not only as a demonstration of the Y1B-17's superior range and navigational capabilities, but was also meant to show how useful the plane could be in attacking an enemy invasion force before it came close enough to American shores to do any damage. The Navy was not at all amused by this particular demonstration, and was furious about what it perceived to be an Army intrusion into the Navy's particular mission. Shortly thereafter, a War Department order came down restricting the activities of the Army Air Corps to within a 100-mile range of the US shoreline.
Y1B-17 serial number 36-157 inadvertently demonstrated just how strong the basic aircraft structure really was. In the summer of 1938, it accidentally flew into a thunderhead during a storm. The violent winds inside the thunderhead flipped the plane over on its back, and by the time the plane had been brought under control, it had spun down through the overcast. Upon landing, the aircraft was found to have bent its wings and had popped some of its rivets, but had remained essentially intact.
The Y1B-17s flew for three years without a serious accident, and were transferred to the 19th Bomb Group at March Field in October 1940.
Serials of Y1B-17:
Boeing Y1B-17 Fortress 36-149/161.
Specification of Y1B-17:
Four Wright R-1820-39 Cyclone radials rated at 930 hp for takeoff, 850 hp at 5000 feet, 775 hp at 14,000 feet. Performance: Maximum speed 256 mph at 14,000 feet. Landing speed 70 mph. Cruising speed 217 mph at 70 percent power. Service ceiling 30,600 feet. An altitude of 10,000 feet could be attained in 6.5 minutes. Normal range 1377 miles. Range with 4000 pounds of bombs was 2400 miles and 3320 miles with no bombs. Dimensions: Wingspan 103 feet 9 3/8 inches, length 68 feet 4 inches, height 18 feet 4 inches, wing area 1420 square feet. Weights: 24,465 pounds empty, 34,880 pounds normal loaded, 42,600 pounds maximum. Armament: Armed with five 0.30-inch machine guns with 1000 rpg. One gun was mounted in each of nose, dorsal, ventral, and two waist positions. A maximum bombload of 8000 pounds could be carried in an internal bomb bay.