|Boeing Turbine Truck|
In the 1950's Boeing installed a turbine engine in a Kenworth truck and put it into service with a freight hauling company. The engine weighed about 200lbs, 2800lbs LESS than the diesel it replaced. It worked well for a couple of years but it had one draw back, fuel economy. It literally got 1.5mpg! Diesels of the day would average 4mpg, a colossal leap. - SwishyFor a journey of 500 miles the turbine would have a weight advantage: the total weight of the engine and required fuel for the diesel would be more than 1,000 pounds greater than for the turbine. So if weight is a critical factor, you are only traveling short distances and cost is no object, a turbine is the engine to use. Boost the distance to 840 miles and the turbine's greater fuel consumption causes the weight advantage disappear and by the time you've gotten to 1,000 miles the advantage is squarely on the side of the diesel.
The same logic can be applied to small aircraft. Bigger airplanes require more power, which requires bigger engines. When you start increasing the size of piston engines, I suspect that the weight grows much faster than the power output. We can build big, powerful diesel engines, but the only place we use them is in steamships.
Inspired by an ad on Craigslist for a turbine powered go-kart, via Posthip Scott.