KW 40 Aircraft Tug

In 1958, Kenworth introduced a new vehicle outside of the trucking industry: the KW 40 aircraft tug. Years prior to this introduction, Kenworth built a couple of prototype aircraft tugs for Boeing, which inspired them to build a commercial aircraft tug that was easier to service with standard automotive components. The KW 40 was spec’d with a Continental gas engine (290 HP / 653 ft-lbs torque), Timken planetary axles, and an Allison transmission – component suppliers well known in the trucking industry. A Carco winch was also an option. Two or four-wheel steering configurations were available. The latter offered a tight turning circle of just 16 feet and crab steering. With ballast weights, the tug weighed from 25,000 to 43,000 lbs. and could pull aircraft up to 400,000 lbs. It had a maximum speed of 10 mph while towing an aircraft and 30 mph unladen. During the 1950s, Kenworth recognized the importance of field service and made vast improvements in this area on the trucking side.

 Following this recipe for success, they held a service school for United Airlines that covered the aircraft tug’s service and operation. Kenworth’s General Manager, RC Norrie; Chief Engineer, Wallace Brown; and field service personnel participated in this class alongside component representatives. The aircraft tug was manufactured at both the Seattle and KW-Dart plants for only a few years. However, it saw operation at not only domestic airports, but also overseas, including at an airport in Paris, France.