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JASC Ships First Fuel Metering Valve Assembly
(FMVA) for the Airbus A-380’s APU
Originally Published, April 2003
JASC is pleased to announce the completion and
shipment of the first Fuel Metering Valve Assembly (FMVA) for the
Airbus A-380’s APU. This new aircraft is scheduled to enter
commercial service in 2006 and will have the largest commercial
Auxiliary Power Unit (APU) ever built. JASC’s FMVA will be
used to provide metered fuel to the aircraft’s APU, the PWC-980A
that is being developed by Pratt & Whitney Canada. (Please see
archived article A380 Contract
for additional details).
The FMVA incorporates an electro-hydraulic 4-way fuel-metering servo,
a pressure compensating By-Pass Valve, Pilot Operated Solenoid and
Shut-off Valve into a single
integrated package.
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Concept drawing of
the A-380 Mega-Transport, courtesy of Airbus Ind. |
JASC’s Developmental
FMVA
for the Airbus A-380 APU |
The heart of the FMVA is the 1st stage electro-hydraulic servo.
This servo is based upon JASC’s 3-way, clevis type, fuel-metering
servo that is currently being used in a variety of applications.
Some of the other applications for this servo valve include: direct
metered flow and pressure compensated flow control for turbine engine
fuel systems and actuator position control.
The highly accurate fuel delivery schedule is achieved
through the incorporation of a
mechanical feedback spring and a precisely shaped metering port
contour. The low cost
feedback spring is used to provide position error, in lieu of an
expensive LVDT. This also
provides additional savings in weight, system integration and unit
volume. The port contour provides an equal percentage flow error
throughout the unit’s operating range.
Some of the features of the Fuel Metering Valve Assembly include:
• Operating pressures up to 1500 psig
• Over 20:1 turn-down ratio
• 0-100 mA servo operating current
• < 0.1 mA threshold
• < 2.5 mA hysteresis
• Fail-safe closed shut-off valve on loss of electrical signal
and/or fluid pressure
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