Sam Wheeler, a renowned American land speed motorcycle racer, has died at age 72 after a racing accident at Utah’s famous Bonneville Salt Flats.

Mike Cook, organiser of the testing event going on this week, says Wheeler was going about 320km/h during a test run when the motorcycle started fish tailing, then sliding and then popped into the air and came crashing down on the caged section where Wheeler was seated.

Intermountain Medical Center spokesman Jess Gomez said Wheeler died on Monday afternoon at a suburban Salt Lake City hospital due to traumatic injuries suffered in the accident.

“We all have real heavy hearts,” said Cook. “Land speed racing is one of the most family orientated sports there is the world.”

Wheeler, an engineer from Arcadia, California, was known as an innovator and pioneer in the sport.

He spent more than two decades building, fine-tuning and racing a motorcycle on which he reached speeds exceeding 300mph (483km/h), said Pat McDowell, a fellow racer and longtime friend. At one time, he held the land speed record for motorcycles, he said.

“He’s was pretty much one of the legends of our sport,” McDowell said. “He did it with his brain, not his wallet.”

Wheeler had been working on the motorcycle in recent years with a goal of setting the motorcycle speed record and surpassing 400mph (643.6km), McDowell said.

Wheeler was perfectionist who knew aerodynamics well, said Bill Lattin, president of the Southern California Timing Association, which is set to host a major racing event at the Salt Flats in August.

“He built that motorcycle by hand. Every single part on it,” Lattin said. “He’s been rebuilding it, making it stronger, faster and more aerodynamic.”

“He was the nicest guy in the world,” Lattin said. “He would do anything for anybody.”