Aerodynamics are a very important aspect of the solar car. The air resistance at cruise speed takes about 75% of the energy to keep it at constant speed. Creating the most optimal shape is crucial for winning the race. Teammembers Lars, Julian and Coen spent six month to reach this goal. The shape of the car determines how aerodynamic the car will be; production of the final body shape was very precisely done.
Plug, the negative of the solar car
The car was split into the upper and under body, to make sure that the car doesn’t get stuck in the mold. A plug is needed to be able to make a mold: a upper and under body is cut into a plug.
A plug has the shape of the upper or under body of the car. It also has flanges to make laminating easier. The plugs are covered with carbon strokes, which are covered with resin by a vacuum. The mold is taken of the plug when it completely dried. The upper and under body of the car is laminated in this negative.
Challenges of a mold
The molds are baked to guarantee the right stiffness, before the molds can go into the autoclave (pressure oven). Baking makes resin softer, meaning that the mold could lightly sag. This would result in a solar car that does not have the most optimal aerodynamic shape. Solar Team Twente and Meilink Group designed a mold support to make sure that the mold wouldn’t sag during baking.
Unique mold support
The mold support consists out of numerous bulkheads in different directions, going underneath the car. This will support the mold when it is mounted on the undercarriage, which will support the mold evenly. It is challenging to find material that will not bend and is also resistant to high temperatures and pressure of the autoclave. Jongeneel B.V. provided special plates for this. The mold support was assembled at Meilink group. The unique mold support gave the solar team the opportunity to meet the high standards of the aerodynamic design. The Red One will cut through the wind and will hopefully be number one!
In the video down below, you can see how we laminated our plugs (from 2:30 min).
Photo: Jérôme Wassenaar