J. Mac McClellan

The new GE H80 turboprop engine on display here is nearing certification and promises to give Pratt & Whitney's venerable PT6 series some serious competition for business-aircraft use.

With the might of GE aircraft engines behind it the H80 is a far different turboprop than its Walter engines ancestor.

A couple of years ago GE teamed with Czech engine maker Walter to upgrade the M601 series turboprops that were an alternative to the PT6, but came up short in key areas of fuel efficiency and engine life.

Then GE acquired Walter and the transformation of the company and the engine was complete.

The result is the H80 with a 3,600 hour TBO that requires no hot section inspection at the midpoint of life as required for most turboprop engines. The H80 can produce 800 shp even on a very hot day so it will maintain its power output at altitude for good cruise performance.

The configuration of the H80 is the same as the PT6 with induction air entering the rear of the engine. Air passes forward through three axial compressors and a final centrifugal compressor that forces the air into the burner section. The hot gasses then move forward over a power turbine that spins a gearbox to turn the propeller.

Applied expertise
GE was able to make large improvements over the original Walter engine by using its expertise in aerodynamics and high-temperature materials. Turbine-engine expertise runs deep at GE, which for years has successfully competed in the turboprop and turbofan airliner fields.
Much of the gain came from a redesign of the compressor inlet to smooth airflow.

The compressor wheels are now blisks, meaning that the wheel and the blades are machined from a single piece of metal rather than having individual blades inserted into a wheel. The airfoil shape of the compressor blades has been optimized based on the vast research GE has done on its jet engines.

Major gains have also been made in the combustion section where a centrifugal fuel slinger is used in place of individual fuel injectors. The slinger atomizes the fuel as it sprays it evenly out into the burner can.

Williams turbofan engines use a similar fuel slinger system in the FJ44 series. Eliminating the fuel injectors is also key to doing away with the need for a hot section inspection.

The new materials used in the gas-generator turbine and the power turbine, plus advanced aerodynamic design of the turbine blades, allows the engine to operate at higher temperatures and pressures than in the past-and that equals improved fuel efficiency.

The gearbox reduces the high speed turbine rpm down to just 2,080 rpm at the propeller and that low prop speed will reduce cabin noise.

Potential plus
The GE H80 should fit easily into engine nacelles designed for the PT6 because the size and shape of the engines are similar, and the same type of duct work for air induction and for exhaust are used.

No new airframe launch customer for the H80 has been announced, but some STC programs are in the works and a new airplane seems certain to follow.

Everybody loves the PT6, but competition is a good thing and it looks like GE and the H80 can be a very viable alternative.

In addition to displaying its turboprop engine here, GE also sponsors the Aviation Learning Center that is located in what was the NASA building.

This year the Aviation Learning Center exhibits feature advances in electrically powered vehicles, including aircraft, along with new technology in batteries and propulsion.