EC120B Helicopter. Photo: Eurocopter
Don't Forget to Make Them Biodiesel-Compatible!
Most helicopters are powered by turbines. This provides a great power to weight ratio, but it also burns a lot of fuel, which is why Eurocopter is now looking at diesel piston engines as a way to make its choppers more fuel-efficient. We're talking about significant savings too, on the order of 40%. But before that can happen, even more power needs to be wrung from even smaller diesel engines (as you can imagine, weight reduction is key for an helicopter engine).
Another benefit would be better high-altitude performance. From Autopia:
Turbine engines used in helicopters lose efficiency rapidly as the altitude increases. Because of the power loss at altitude, helicopter operators that often fly in the mountains use helicopters with more powerful engines to compensate. Larger engines are even thirstier engines, increasing an already large fuel bill.
The diesel engines Eurocopter is investigating would be turbocharged. The use of a turbocharger results in an aircraft being able to maintain full power to a higher altitude where the air is thinner. This "turbo normalizing" doesn't necessarily mean a boost of power at lower altitudes. Instead, the boost from the turbocharger is used to compensate for thinning air as the helicopter is flown at higher altitudes. Gasoline-powered piston helicopters, including the classic Bell 47, have long used turbocharged engines for the same reasons.
I would be nice if Eurocopter (and other companies looking at diesel engines for helicopters) designed the powertrain to be compatible with biodiesel so that if in the future more biodiesel becomes available (from algae, for example), it's choppers are future-proof and potentially carbon-neutral. Tests have already been done flying airplanes on bio-d, why not helicopters?
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