Dennis Manning (left in photo) is a supremely talented and self-taught designer and fabricator who devoted his life to pursuing the motorcycle land-speed record. He built the streamliner that multitime AMA Grand National Champion and AMA Motorcycle Hall of Famer Chris Carr (right in photo) rode to a world-record 350.8 mph at the Bonneville Salt Flats in 2006.
Here are 10 facts related to Manning, who was inducted into the AMA Motorcycle Hall of Fame in 2006.
1. In 1970, Harley-Davidson racing chief and future AMA Motorcycle Hall of Famer Dick O’Brien pulled together the talent and resources for an assault on the motorcycle world land speed record. In addition to rider and future AMA Motorcycle Hall of Famer 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.
2. 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. He says: “Every other kid my age wanted to be a major league outfielder. I wanted to be Mickey Thompson."
3. Manning tried road racing and drag racing but quickly turned to the 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.
4. 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 Rayborn, based on his great popularity and name recognition, despite the fact that Rayborn had absolutely no Bonneville experience.
5. Manning agreed to a performance-based deal of $10,000 for a world record and reimbursement for his hotel expenses if no world record was earned.
6. 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.
7. 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.
8. Rayborn crashed and slid the liner down the course on its side several times before he learned to control the machine. 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.
9. Finally, when it was decided that Rayborn knew how to control the liner, the crew installed what they called 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 record of 251.92 mph set by future AMA Motorcycle Hall of Famer Don Vesco. Harley-Davidson then had all the reason it needed to continue its claim to be “No. 1.
10. On Sept. 7, 2006. With 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 a mark set by Dave Campos that had stood for 16 years.