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Y-4 Horizontal Periscopic Bombsight

Designed for installation in the nose of B-47B and B-47E bombers, the Y-4 Y-4 Horizontal Periscopic Bombsight provided an optical view of bombing targets. (U.S. Air Force Photo).

Designed for installation in the nose of B-47B and B-47E bombers, the Y-4 Y-4 Horizontal Periscopic Bombsight provided an optical view of bombing targets. (U.S. Air Force Photo).

B-47 bombardier-navigator (blue) and the Y-4 bombsight (red).

B-47 bombardier-navigator (blue) and the Y-4 bombsight (red).

Unlike previous USAF medium bombers, the B-47 carried a combination bombing and navigation system operated by a bombardier-navigator. By automating many functions, this system reduced crew size by eliminating the need for a separate bombardier and navigator.

The bombardment part of the system included the Y-4 bombsight, an automatic pilot and an AN/APS-23 radar linked to a computer. Using these components, the bombardier-navigator could bomb targets either visually or by radar.

Designed for installation in the nose of B-47B and B-47E bombers, the Y-4 bombsight provided an optical view of bombing targets. The geared lens mount of the Y-4 moved to keep the line-of-sight on the objective. Unlike the World War II bombers of the previous decade, this allowed the pilot to take evasive action as he approached the target without the operator losing his aiming point.

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Mask Policy:
In accordance with the updated guidance released by the Center for Disease Control and Prevention (CDC), the Department of Defense (DoD) and Wright-Patterson Air Force Base, the National Museum of the U.S. Air Force will require all visitors to wear face masks indoors effective July 30, 2021 until further notice.

Visitors ages three and up will be required to wear masks while indoors at the museum. This policy applies to all visitors, staff and volunteers regardless of vaccination status. Visitors may wear their own masks or a free paper mask will be provided. Cloth masks will also be available for purchase in the Museum Store.
Additional information available here.

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