Framework V2 - Construction

The basic contruction philosophy is a 29mm tube from base to tip which will carry the thrust load and distribute it to a framework which will transmit the force to the skin. The framework is designed to balance the loads of thrust and aerodynamic drag. The frame is a series of balsa trusses running lengthwise down the core tube. The trusses are joined by small strips of 1/64th plywood to provide torsional strength and to support the skin.

The ribs were built directly on the plan against a straight-edge, then glued to the body tube. The 1/64th plywood reinforcement was built onto the rocket itself. In the fin area, some of the balsa structure is laminated with basswood strips for extra strength.

Laying out a rib	Gluing ribs to core	First assembly
Fin detail	Nose rim brace
Fin with brace	Internal brace	Heavy fin brace

Layout

The ribs are built directly on the plan. A sheet of wax paper makes a translucent non-stick cover, and a heavy foam-core back allows the ribs to be secured with straight pins. It helps to build against a straight-edge to ensure that the baseline will lay flat against the core tube.

When the structure is completed, the structure is a core tube with eight truss "vanes" sticking out from it. A few diagonal braces were then added between the trusses to make the whole structure rigid. The fin trusses got a few extra internal braces to improve their rigidity. The aft edge of the "nose cone" needed bracing between the trusses to make it rigid (see above). One heavy basswood strip was added from the outer tip of the fins back to the core tube to help the fins withstand the shock of landing. This process of adding internal braces is very quick an easy - pieces can be cut to fit in place on the structure and glued directly into place.

Recovery System

Because the interior of the rocket is cluttered with a network of ribs, special care must be taken to ensure that the recovery system does not become tangled on the interior structure. To do this, special wedge-shaped compartments were created between the ribs by lining them with typing paper. Three compartments were created, one for each chute and a smaller one to contain the shock cord.

Recovery system compartments