Porting of the Kohler free air engine was revised to move peak torque down to a lower RPM to go with the new clutching. A new drive clutch, the Comet 94C, was engineered for the project using pucks instead of ramps and rollers for simplicity and durability. The diameter of the driven clutch had to be increased, while the number of teeth on the drive axle sprockets was reduced to provide adequate all-around performance. The two had race driver and development specialist Dale Cormican build a quick prototype at his shop to test the concept – christened “Little John,” it was deemed viable for commercial development.Ĭlutching was the major hurdle of the time for direct drive. Ron Leonard, manager of engineering at the Horicon Works, asked project engineer Tom Lohr and powertrain engineer Dick Teal if the gearbox and jackshaft could be eliminated, and Teal determined that this approach might work. The Spitfire began with a January 1976 conversation among a trio of snowbound John Deere engineers about how to reduce the cost of manufacturing snowmobiles. Was it more fun than a barrel of monkeys (as some of us believed), or was it an accident looking for a place to happen, like detractors concluded? The Beginning And although popular at first, its sales declined quickly. Images from The John Deere Spitfire earned a place in snowmobile history as the first direct drive sled.
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