Vacuum cleaner power
Nuna 4 had a super-efficient motor. The power needed to race Nuna 4 at 110 km/h through the Australian outback is equivalent to that of a vacuum cleaner.
Upright for the first time
For the first time, the driver of the solar cars had to sit upright. In previous designs, the driver lay flat in the body. This change brought Nuna 4's design closer to a regular car.
Special solar racing tires
Nuna 4 used new tires designed specifically for solar racing. These tires had one of the lowest rolling resistances on the market and were filled with nitrogen. These same tires continued to be used for up to fifteen years afterward.
The previous solar cars were so fast on Australian roads that the rules of the 2007 World Solar Challenge were drastically changed. This presented a new challenge.
While previous Nuna models were covered with solar panels in every possible spot, a maximum panel area of six square meters was now imposed. Additionally, the driver had to sit upright instead of lying down for better aerodynamics. This forced the team to build a completely new and innovative solar car.
The team faced challenges in Australia, including replacing the panel insulation just a day before the race due to vibrations and heat from extensive testing. They worked through the night and finished just hours before the race. During the race, they dealt with seven flat tires due to strong crosswinds, causing the tires to wear excessively.
Unlike the previous Nuna cars that completed the race in five days, the last day of Nuna 4's race was quite suspenseful. With 740 kilometers left, they weren't sure if they would make it to the finish line on the fifth day. Favorably, strong tailwinds pushed Nuna 4, and they crossed the finish line just in time.
1st place— Bridgestone World Solar Challenge 2007
4.72m x 1.68m x 1.10m
6 sm2 Gallium Arsenide
30 kg Li-polymer