World War Photos

B-29 wings on assembly line at Renton Plant

As the engineering of the Model B-345 design progressed through 1940 and into 1941, Boeing aerodynamicists were particularly interested in the Davis wing, developed by freelance aeronautical engineer David R. Davis for Consolidated Aircraft. This wing was already being used on the Consolidated B-24 Liberator and was highly regarded for its aerodynamic efficiency.

Davis Wing and Its Attributes

• Development and Testing:
  • The Davis wing underwent wind-tunnel evaluations at the California Institute of Technology (CalTech), where engineers discovered its lift-to-drag efficiency was far superior to contemporary wing designs, surpassing them by about 20%.
• Design Characteristics:
  • Full Cantilever Design: The wing featured a long, narrow chord with an advanced high-lift and low-drag aerofoil design.
  • Flush Riveting: This technique reduced drag and improved aerodynamic efficiency.

Boeing’s Dilemma and Solution

Despite the apparent advantages of the Davis wing, Boeing faced a significant challenge: Consolidated had exclusive rights to the Davis wing and did not have to share it with competitors. This was affirmed through numerous congressional debates and military hearings.

Boeing’s Alternative: The 117 Aerofoil Wing

Unable to use the Davis wing, Boeing developed its own wing design, the 117 aerofoil, which turned out to be highly effective in its own right.

• Design and Structure:
  • Inboard Section: Permanently attached to the fuselage and contained integral fuel compartments with self-sealing tanks.
  • Outer Panels: Removable with detachable tips, enhancing maintenance and flexibility.
  • Ailerons: Equipped with trim tabs and hinged to the outboard panels, aiding in aircraft control.
  • Fowler Flaps: Electrically operated and formed the lower surface of the inboard wing trailing edge, from the fuselage to the outboard wing joint, providing enhanced lift during takeoff and landing.
  • Leading Edge Sections: Removable, providing access to internal components such as cables, tubing, and wiring.

Significance of the 117 Aerofoil Wing

• Performance: Although Boeing could not use the Davis wing, the 117 aerofoil wing proved to be a highly capable design. It provided excellent aerodynamic efficiency and structural integrity, contributing significantly to the B-29’s performance.
• Innovation: The development of the 117 aerofoil wing demonstrated Boeing’s ability to innovate under constraints and develop competitive technology in the face of proprietary limitations.

The B-29 Superfortress did not benefit from the Davis wing due to Consolidated’s exclusive rights, but Boeing’s 117 aerofoil wing design, with its advanced features and efficient performance, ensured the B-29 remained a formidable and innovative aircraft during World War II.