World War Photos

Mosquitoes fuselage assembly

The construction of the Mosquito fuselage is a remarkable example of innovative use of materials and techniques, particularly for its time. Here’s a breakdown of the key aspects:

Fuselage Construction

1. Building Process:

   • The fuselage is constructed in two halves using half-jigs, with a longitudinal split along the top and bottom from nose to tail. These halves are built simultaneously to ensure uniformity in conditions like temperature, which could affect the materials.
   • The halves remain together through the entire assembly process and are not interchangeable with those from other aircraft.

2. Materials and Structure:

   • The fuselage employs a sandwich skin construction:
     • Outer Layer: Plywood
     • Core: Balsa wood
     • Inner Layer: Plywood
   • At bulkhead attachment points, the balsa core is replaced with a spruce ring for additional strength.
   • The skin thickness varies from 1.5 mm to 3.0 mm, depending on the structural requirements.

3. Bulkheads and Reinforcement:

   • There are seven bulkheads from nose to tail, each constructed from two plywood skins separated by spruce blocks.
   • The plywood skin’s orientation varies with stress considerations; it is applied diagonally where strength is critical and straight where less strength is required, optimizing material use.

4. Attachment Points and Reinforcement:

   • Direct attachments to the skin are avoided. Instead, holes are drilled into the ply and balsa core, where Bakelite plugs with ply flanges are inserted and glued. The flanges help distribute loads when screws are used.
   • The wing pick-up points are made from laminated spruce and integrated into spruce inserts within the skin, providing a robust area for load distribution.

5. Assembly and Finishing:

   • During assembly, various components like electric leads and oxygen bottles are integrated, with particular attention to the joints between the halves.
   • These joints are scarfed with Vee notches, overlaid with plywood strips inside, and a ply insert outside for reinforcement. Clamps secure the fuselage until the glue sets.
   • The fuselage is covered with fabric and doped after assembly to provide a smooth, aerodynamic surface.

Adhesives and Weather Resistance

• The construction is transitioning from casein glue to beetle glue (urea-formaldehyde resin), which offers superior water resistance and weather durability.