Engine, Fire Protection And Fuel; Engine - Honda HondaJet HA-420 Pilots Operating Manual

Honda Aircraft Company
HA-420 SYSTEMS
POM DESCRIPTION

ENGINE, FIRE PROTECTION AND FUEL

ENGINE

Introduction
Two GE Honda Aero Engines HF120 turbofan engines are pylon
mounted in a patented Over-The-Wing Engine Mount (OTWEM)
configuration.
The GE Honda Aero Engines HF120 engine is a twin spool counter-
rotating medium bypass ratio turbofan engine. The HondaJet HA-420
engine produces 1997 lbs. of thrust at sea level, flat rated to
77 ºF (25 ºC).
The engine features an advanced single stage wide-chord fan with a two
stage axial low pressure (LP) compressor driven by a two stage axial low
pressure (LP) turbine on the LP shaft. The single stage centrifugal
compressor is driven by a single stage high pressure (HP) turbine on the
HP shaft. The engine does not incorporate any variable geometry, but
does have a Bleed Off Valve (BOV) in the HP compression section that
is opened to increase compressor stability during acceleration. The
HF120 has a fully mixed exhaust. Fuel is pumped to the reverse flow
combustor from the gearbox driven pump and metering unit which is
controlled by the Full Authority Digital Engine Control (FADEC).
Thrust is managed via a throttle quadrant mounted Rotary Variable
Differential Transformer (RVDT). The Exhaust Gas Temperature (EGT)
is measured downstream of the second LP turbine and the FADEC
calculates Interstage Turbine Temperature (ITT) from the measured
EGT.
HJ1-29000-005-001
October 30, 2016 1-75
FOR TRAINING PURPOSES ONLY