Diesel-powered helicopters in the works

Eurocopter, the world’s biggest helicopter-maker, has announced that it is keen on developing a helicopter with a diesel-powered engine within 5 years.

Photo: Eurocopter's new diesel engine from EcoMotor

Eurocopter put on show an example of a possible diesel piston-engine design at the recent Heli-Expo held in Houston, the United States.

According to Eurocopter, the fuel-efficient diesel piston-engine, or the powerplant, could replace turbine engines in the company’s light, single-engine helicopters.

Oliver Jouis, Eurocopter’s chief of environmental affairs, says the company will adapt a diesel powerplant for use in one of its smaller helicopters. Diesel, according to him, has reached a level of technology that can be “transferred to the world of helicopters.”

Diesel engines, Oliver Jouis explains, have proven to be highly successful in the automotive industry in the last one decade. The present-day diesel motors are efficient, quiet, and their power-to-weight ratio is very good, he says.

Also, helicopters with diesel engines can perform better at high altitude, according to Oliver Jouis. Another advantage of a diesel engine is that its cost of acquisition will be lower than that of the turbine engine.

At present, all helicopters manufactured by Eurocopter are turbine-powered. Though turbine engines are highly reliable and also provide a large quantity of power for the weight of the motor, they are also fuel- guzzlers.

Since the cost of fuel for even a small helicopter can come to several hundred dollars per hour, any reduction in the use of fuel is good news for operators of helicopters, according to a statement from Eurocopter.

The company’s EC120 helicopter is likely to be fitted with the diesel engine. The EC120 helicopter is now powered by the Turbomeca Arrius turbine engine.

Since turbine engines used in helicopters lose efficiency fast at high altitudes, helicopter operators flying in the mountains regions use helicopters having more powerful engines in order to compensate for the loss of efficiency, Oliver Jouis said. The result is that bigger engines use still more fuel, further raising the huge fuel bill.

The diesel engine that Eurocopter plans will be turbo-charged since a turbo-charger can maintain full power at higher altitudes where the air is thin.

Eurocopter has not yet revealed what kind of diesel engine it will use. The company said in the statement that it will not be manufacturing diesel engines, but will work with an engine-manufacturer in order to develop its diesel powerplant.

At the Heli-Expo held in Houston, Eurocopter displayed a 2-stroke diesel engine – a multi-fuel engine made by the United States-based EcoMotors International.

According to Eurocopter, the 2-stroke diesel engine uses 2 opposed pistons per cylinder – an arrangement that produces one power stroke with every revolution of the crank for each cylinder.

The company said is also considering many other options – including the more traditional 4-stroke diesel engines.

It was in April 2009 that the first diesel-powered helicopter started flight-tests. The helicopter, named Delta D2, was made by Graeme Smith, an Australian helicopter designer.

Graeme Smith, from Brisbane, Australia, developed the first diesel-powered helicopter after working on it for about 6 years.

The crucial component of the Delta D2 helicopter is its light-weight, aluminium-cast Deltahawk V4 diesel engine that produces 180 hp with a dual turbo supercharger. The weight of the diesel engine is only 360 lbs.