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