A supremely talented and self-taught designer and fabricator, Denis Manning has devoted his life to pursuing the motorcycle land-speed record and his innovative streamliners have succeeded on more than one occasion. Manning, also the founder of aftermarket motorcycle exhaust pipe company BUB Enterprises, built the streamliner that multi-time AMA Grand National Champion Chris Carr rode to a world-record 350.8 mph at the Bonneville Salt Flats on September 7, 2006.
It wasn't the first time a Manning-designed streamliner was the fastest motorcycle in the world. In 1970, Harley-Davidson racing chief Dick O’Brien pulled together the talent and resources for an assault on the motorcycle world land speed record. In addition to rider Cal Rayborn, the team included Clyde Denzer and John Pohland of the H-D racing department staff, engine builder Warner Riley, fuel guru George Smith, Sr., and a 24-year-old self-taught designer and fabricator named Denis Manning.
Manning had become a Bonneville fan at the age of 13 when he saw Mickey Thompson race his four-engine land speed record car, Challenger, at the salt flats.
"Every other kid my age wanted to be a major league outfielder," said Manning. "I wanted to be Mickey Thompson."
After some experience with road racing – for which he found himself too tall – and drag racing, Manning turned his sights toward design and fabrication of land speed record streamliners. The machine that Harley-Davidson used in 1970 was Manning’s second liner, built on the garage floor of his duplex. Its construction had begun in 1968, and it made its maiden voyage on the salt in the fall of 1970, where Manning piloted it to a one-way speed of 187 mph with a stock Sportster engine running on gasoline.
Harley-Davidson scouts at Bonneville reported the event to O’Brien, who decided Manning’s chassis was just what he needed for a hastily organized record attempt. But O’Brien wanted Manning for his know-how in designing and setting up a streamliner, not as a pilot. For that he wanted Cal Rayborn, based on his great popularity and name recognition, despite the fact that Rayborn had absolutely no Bonneville experience.
"I was 24, newly married, and holding down three jobs to feed my family and fund my racing program," Manning recalled, "and I jumped at the chance to be part of an official Harley-Davidson effort."
Manning agreed to a performance-based deal. "O’Brien offered me $10,000 if we got a new world record, and reimbursement for my hotel bill if we didn’t," Manning said. "I took the deal."
The 15-foot-long streamliner, which Manning constructed around his own physique, needed to have its passenger compartment modified for the 5-inch-shorter Rayborn. Its main structural unit was the compartment itself, an aluminum tube with a cross section of only 23 inches, with aluminum bulkheads riveted into each end. On these bulkheads are bolted tubular steel sub-frames: one in front to carry the front wheel, suspension and steering mechanism, and one in the rear to contain the engine and drive train, fuel tank, air bottle to drive pneumatic skids, and drag chute.
Lying totally prone, the pilot looks out plexiglass windows on either side of the shell. There are plexiglass windows in the nose as well, but they are nearly useless, because they are obscured by the front wheel and the rider’s knees. With most streamliners, the rider sits a little higher, so he can look forward through a small windshield. With Manning’s design, he was going for the smallest frontal area he could achieve, since air resistance increases at a geometric rate as speeds go higher beyond 200 mph.
Cal Rayborn crashed and slid the liner down the course on its side several times before he learned to control the machine, and on one occasion he sent it into a horrendous end-over-end tumble. Thanks to the structural integrity of Manning’s chassis, Rayborn was not injured and the machine was reparable.
Finally, when it was decided that Rayborn knew how to control the liner, Warner Riley and George Smith – both of whom had extensive experience at Bonneville – were asked to install the "Godzilla" engine, an 89-cubic-inch Sportster-based monster burning 70 percent nitromethane. With this engine, Rayborn achieved 266 mph on an outgoing run, and he did 264 mph on his return, despite a broken valve seat that caused the engine to fail 200 feet before the end of the course. These rides resulted in a two-way average of 265.492 mph, breaking a previous Don Vesco record of 251.92 mph, and Harley-Davidson had all the reason it needed to continue its claim to be "Number One."
In recent years, Manning has returned to the salt as both competitor and sponsor of land speed trials through his business, BUB Enterprises. Manning's most recent streamliner set a new FIM world record on September 7, 2006. With Chris Carr at the controls, Manning's streamliner completed a two-way run with an average speed of 350.8 mph, breaking a record that had been set just two days earlier — both of which toppled the mark set by Dave Campos that had stood for 16 years.
In a lifetime quest for ultimate speed, Manning is on record as the builder of the fastest motorcycle ever.