The mechanical systems team is responsible for the motorcycle suspension, frame, brakes, ergonomics, drivetrain, and fairing. Mechanical systems team members make heavy use of kinematics, dynamics, structural analysis, and aerodynamics. Computer aided design, finite element analysis, and computational fluid dynamics are among the many essential tools used in the design process.
The suspension of the motorcycle is responsible for ensuring continuous contact between the tires of the vehicle and the ground while maintaining rider comfort. The front suspension is a telescopic fork design attached to the frame via the steering tube and triple tree clamp. The rear suspension is a monoshock design utilizing a swingarm mounted linkage to achieve a desired leverage ratio curve. Due to its relatively tall center of gravity, a motorcycle’s suspension must accommodate a high degree of weight transfer between the front and rear wheels making suspension design one the most technically difficult projects on the bike.
The frame is the primary structural member of the motorcycle responsible for providing adequate stiffness and mounting locations for integrating all the motorcycle systems. The frame is of tube construction utilizing 4130 steel tubing and includes dimpled sheet metal gussets as reinforcement in high load areas. The frame utilizes the motor and accumulator case as structural members of the system providing for greater mass optimization.
The front and rear braking systems act independently of each other as dictated by competition regulations. Force inputs from the hand lever or the brake pedal are amplified hydraulically and transmitted through the brake lines to the brake calipers. Minimum brake force of 300 N and 250 N for the front and rear wheel respectively are required by the competition. MotoStudent will provide the brake calipers, hand levers, and foot pedals. Individual teams have autonomy in designing their own brake rotors, linkage systems, and brake pads.
Power to the rear wheel is transmitted from the electric motor’s output shaft via the front sprocket through a steel chain to the rear sprocket. A chain drive is durable, cost effective, easy to maintain, and effectively transmits power with negligible power losses. A gear ratio of 1:4.5 is used to prioritize top speed over acceleration.
The purpose of the aerodynamics team is to minimize both the aerodynamic drag force and lift force acting on the motorcycle while considering rider ergonomics. Aerodynamic drag and rolling resistance are the only two forces which oppose the motion of the motorcycle. Drag is generated by the interaction and contact of the motorcycle with air resulting in pressure differentials forming between the front and rear of the motorcycle as well as viscous (friction like) effects. Minimizing drag allows for a higher top speed, more efficient fuel consumption, and faster acceleration. Maintaining slight downforce (negative lift) at moderate speeds with a forward biased center of pressure helps to prevent the onset of a wheelie (when the motorcycle’s front wheel lifts from the ground) during high acceleration which is often observed during corner exit. However, high downforce is not desirable as it will tend to push the motorcycle out of corners.