This video documents the second phase of a project to build a man-carrying airplane primarily from cardboard, focusing on the construction and assembly of the fuselage and tail section. The creator follows an oversized model airplane design, using large cardboard sheets reinforced with internal laminated layers ("doublers") and triangular gussets. Key structural challenges are addressed, including the creation of a strong wing-to-fuselage joiner using folded cardboard and minimal plywood, and building a lightweight yet rigid tail assembly. Reinforcement is a major theme, with fiberglass tape used for control surface hinges and a "flying wire" system of tensioned strings added to secure the tail. The video shows the complete assembly of the airframe, which weighs approximately 75 pounds, and includes a successful static load test with the creator in the cockpit. The video concludes with a Q&A session addressing viewer feedback from the previous installment and outlines the next steps: building a power system, controls, and a droppable landing gear.
Building a Man-Carrying Cardboard Airplane: Fuselage and Assembly
0:18 Fuselage Construction: The fuselage is built like a large-scale model airplane using large cardboard panels. Key areas are reinforced with multiple layers of cardboard ("doublers") and internal triangular gussets to ensure structural integrity.
2:42 Reinforced Floor: A strong, sandwich-style floor is engineered by placing a custom-made corrugated cardboard structure between two flat sheets, creating a lightweight but rigid platform for the pilot.
3:50 Wing Mounting System: A critical wing box structure is created to join the wings to the fuselage. It uses strong, folded cardboard for the main structure, with small plywood inserts added only where bolts pass through to prevent tearing, adhering to a "95% cardboard" rule.
9:48 Tail and Control Surfaces: The horizontal stabilizer, vertical stabilizer, elevator, and rudder are constructed from laminated cardboard. The creator opts for this method over folding for better accuracy on these smaller components.
11:54 Hinge Testing and Application: Various types of tape are tested for their strength and adhesion to cardboard. A strong, fiber-reinforced tape is chosen to create durable hinges for all the control surfaces (elevator and rudder).
15:52 Tail Reinforcement with Flying Wires: To prevent the tail section from ripping off in flight, it is secured with "flying wires"βa system of tensioned strings running from the fuselage to the tips of the horizontal stabilizer, creating a strong, triangulated truss.
18:21 Total Airframe Weight: With the wings attached, the entire airframe weighs approximately 75 pounds (35 lbs for the fuselage and tail, 40 lbs for the wings), which is comparable to a real ultralight aircraft.
20:28 Backup Safety Sling: As an extra safety measure, a sling made of strong fiberglass tape is wrapped around the wing mounts and fuselage. This is designed to hold the wings on as a backup if the primary cardboard and glue joints were to fail under load.
21:29 Static Load Test: The creator sits in the cockpit of the fully assembled plane while it is lifted off the ground. The test is successful, showing the cardboard structure is bearing his weight without relying on the backup tape sling.
27:35 Next Steps: The video concludes with the airframe construction complete. The final phase of the project will involve building a droppable landing gear carriage, installing the electric power system, and rigging the flight controls.