All the dimensions for frames and seat assembly was obtained from research and previous design. To put all the dimensions into prospective, a full scale cardboard prototype was creates shown in figure 11. The purpose of this prototype was to visualize the overall frame and seat assembly. From this prototype the team learned that the fork assembly shown in red was longer than expected. Initially, the fork was designed to be 43.18cm (17in) long when the rear wheel diameter was only 33 cm (13in). Having a long fork assembly will increase the chance of failure as well as make the vehicle longer which may also cause high drag. It was determine from this prototype that the fork can be shorten by almost 10cm (4in) which will reduce the overall length and weight of the vehicle. Since this prototype was not strong enough to sit on to check the position and the angle of the seat, location of the crank-set, and clearance between the front two wheel, another prototype was made using wood.
Second prototype was made using wood which is strong enough to sit on. The actual crank-set, and the wheels were mounted on the prototype to replicate the real tricycle shown in Figure 12. While the overall vehicle felt comfortable, several problem encountered when a person tried to sit on it. One problem was that the wooden prototype broke at a location where the seat is connected to the main frame shown using a red circle when a rider tried to sit on it. Force from the rider’s weight caused the frame to break off at the joint. This may not happened in the actual design because the actual will be made from single piece. Another problem encountered with the position of the crank set where the initial position did not give enough leg extension for the rider. Thus the crank-set was moved 5.08cm (2in) away from the initial position shown with the red arrow.
To make the vehicle light weight yet durable, carbon fiber with core foam reinforcement is used to fabricate the frame, roll-cage and the seat.
