executives realized they could gain an edge over other manufacturers by creating a purpose-built racing snowmobile, and in 1970 assembled a four-man design team headed by Duane Aho for that purpose. Their efforts produced the first Thunderjets in 1971, but the prototypes didn't perform well. Testers reported slow acceleration, handling issues at high speeds, and overall poor driving experience. The design team realized that while they knew how to build a snowmobile, they were unfamiliar with snowmobile racing. One tester, a then-unknown racer named Jim Adema, offered some valuable design input, and became part of the Thunderjet design team. The redesigned Thunderjets produced in 1972 were revolutionary compared to the larger, more powerful racing snowmobiles of the time. They were small, sleek and light, with a low center of gravity. Critics cited their diminutive size, and gave them unflattering nicknames such as "Thunder Chicken". However, they quickly captured the attention of racers and racing fans with their ability to turn tighter and at higher speeds than the larger, heavier models. With lightweight aluminum frames, high-horsepower Yamaha engines and simple aerodynamic design principles, the Thunderjets dominated racing circuits in the early and mid-1970s, winning many awards for racers and Sno-Jet itself. Racing exclusively for Sno-Jet, Jim Adema became famous. In 1973 and 1974 he won snowmobile racing's most prestigious prize, the Kawartha Cup. Within a few years, other manufacturers had emulated the Thunderjet's revolutionary compact design. As a result, many of the innovations introduced by the Thunderjet can be seen in snowmobiles produced today. On December 14, 1975, during a race at Ironwood, Michigan, Jim Adema was killed in an on-track collision. For the first time, he was driving a new Yamaha racing snowmobile rather than a Thunderjet. External links Blake Read's Sno-Jet Page Snowmobile brands