The turbine engine is probably the biggest weakness of the Abrams tank. That thing is thirsty, very thirsty, expensive to maintain, have a huge heat signature and the exhaust heat prevent soldiers from taking protection behind the tank during urban warfare. It should also be remembered that fuel in a warzone can cost $50 a gallon if we include the costs of fuel distribution.J.A.W. wrote:livinglikethathuh wrote:The comments regarding aircraft turbine engines are inefficient at cruise have little ground.
At altitude, as the air density drops, the maximum thrust of the engines also drop, so they actually operate at %85-90 N1 at cruise. When an aircraft has an engine failure at altitude, the first thing it does is to DESCEND, as it simply does not have enough power to stay in the air when that high. So yes, jet engines are most efficient at full thrust, and they operate pretty close to that at cruise.
Twin engine fighter jets typically shut down one engine when loitering, as they have enough power to sustain a high (>30000 feet) altitude with one engine operating at military power.
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I think turbine engines will have some use for ground vehicles sooner or later, because by design, they have the potential of operating at a higher efficiency than reciprocating engines. Theoretical maximum for diesel engines is ~%55 and ~%65 for turbine engines, the key differentiator being the compression ratio. It is currently impossible to efficiently scale down turbine engines currently, but I believe that hurdle will soon be overcome.
Lastly, there is one ground vehicle application of a turbine engine that I'd like to mention:
http://images.tapatalk-cdn.com/16/02/11 ... 5530b2.jpg
68 tons, 1500 hp, top speed ~85 kph (although governed to 75 kph). Rather thirsty though...
Yeah, for sure - that "rather thirsty" Chrysler gas-turbine M1 tank serves as fairly signal evidence of the inherent limitations..
Here is a NASA proposal that shows the potential for a high efficiency 2T diesel ICE helicopter mill to better the gas-turbine..
http://www.ntrs.nasa.gov/archive/nasa/c ... 001160.pdf
Of course, when the Abrams was designed IR sensors weren't as good as today, and since it was designed to battle the Soviets in Europe fuel could be distributed in advance. But for the next version, M1A3 I suspect the gas turbine will be dropped in favor of a diesel.