1961 International Harvester HT-341 Turbine Tractor
If the 1960s were the jet age, International Harvester wanted to be in on the action -- even with its tractors. The company owned a subsidiary, Solar Aircraft Company, which was a major manufacturer of turbine engines in its own right. Someone at the parent company had the brilliant idea to marry the two.
And so was born the HT-341, a concept tractor that debuted in 1961. It was powered by a small turbine engine, the kind used to power auxiliary systems like air conditioning and starter motors on jet-propelled aircraft.
Why didn't it catch on, you may wonder? That little turbine could produce a lot of power -- 85-horsepower (63.4 kilowatts) from a 90-pound (40.8-kilogram) unit, and an unbelievable 57,000 revolutions per minute -- but it took massive amounts of fuel to do so. And it was noisy. Really noisy. Another complication was that the turbine needed a lot of filtered air to operate.
The HT-341 never saw production, and this prototype was also added to the collection at the Smithsonian Institution.