CT Safety Cabin Design
The design of the CTLS carbon fiber cockpit has been intentionally done following reliable design principles known from the passenger cabins of modern cars. In cars the design is done so as to transfer crash loads through the passenger area to the crash-zones at the end of the vehicle, so that the cabin remains stable while the energy is absorbed in the periphery areas. In cars this is done by the following load paths:
front wall beams transfer the loads to the A-pillar base and to the center tunnel between the passenger seats (where the transmission and exhaust are normally routed)
A-pillar is designed as stable beam to transfer the load up to the roof rail and down to the sill beam.
Sill beam is designed compression stable to support between the wheels in a crash and avoid intrusion.
Roof rail is designed as stable compression beam to avoid roof collapse.
B- Pillar is designed as stable spreader between roof rail and sill beam to avoid collapse and support side impact.
All means begin at the front of the passenger cell and extend beyond the passenger cell, routing the loads through the cabin.
In some cars, sandwich floor sections provide additional stiff plates below the passengers, supporting tunnel and sill beam.
Looking at the CT models safety cabin you can find all these key design features as well.
Figure 1 shows the key elements of the fuselage. Figure 2 illustrates the generalized force flow in the CTLS, resulting from the assembly of the components shown in Figure 1:
Forces are introduced in a crash from the engine and nose gear through the big engine mount (1). The big engine mount serves as lead spreader and front beam. Loads are transported from this metal structure to the A-pillar nodes and to the center tunnel.
Forces flow from the strong A- Pillar (2) (designed as stiff carbon fiber box-beam) up to the roof and down to the door sill.
The door sill (3) is designed as closed profile to transport the loads backwards, as well in the sill as in the sandwich composite shell.
The fuselage root rib area (4) is designed as a closed carbon fiber beam working as stiff roof rail and transports the loads backwards.
The middle of the cabin is stiffened with a tunnel (5) that extends from the nose gear attachment area to beyond the luggage compartment.
The cabin is closed at the end with the main bulkhead (6) that serves together with the door sill as B- pillar. All longitudinal elements extend to and beyond this main bulkhead.
The floor section below the seats is designed as double-walled structure (sandwich floor) with the “Pyramids” (7) installed to the cabin floor, supporting the seats.
The inner laminate of the cabin skin is done in Aramide, providing best occupant protection against splintering. The outer skin is designed as carbon fiber providing maximum stiffness and strength
The suitability of this design has been proven in service now for 13 years. Accident history shows that the cabin provides a maximum of occupant protection even in severe crash.