High Speed Ground Tests Imminent
As we enter the home stretch towards AirVenture 2008, these
are busy times for a pair of single-engine jet development
programs... and the question is, which will fly
first? Hot on the heels of news Cirrus is now ground-testing
its
"the-jet" concept, now comes word that
the first time in Piper Aircraft's 71-year history, the sound of a
turbofan-powered Piper airplane was heard when the PiperJet Proof
of Concept's engine was started and tested on June 19, 2008.
Piper officials tell ANN the first engine run gave a
"personality" to the PiperJet Proof of Concept (POC) airplane, with
the distinctive sound generated from the Williams FJ44-3A engine
mounted high in the vertical tail. The unique look of the PiperJet
POC now comes with a unique sound like no other Piper built
before.
The first engine start and following operational tests were
flawless. The Williams engine in the PiperJet incorporates a full
authority digital engine control (FADEC) system, resulting in the
pilot simply pressing the starter button, monitoring the engine
speed as the engine spools up, and then bringing the thrust lever
forward to the run position at a predetermined engine speed. All
other functions are automatically controlled, including the
initiation of an automatic engine shutdown sequence if any
unforeseen problems occur during the start procedure. PiperJet
pilots will really enjoy the peace of mind the Williams FJ44-3A
engine provides as they start the engine in various conditions of
heat, humidity and altitude.
After the initial engine starts and operational checks were
completed, the PiperJet moved forward under its own power for the
first time. Piper test pilots began their evaluations with low
speed taxi tests to verify nosewheel controllability and authority.
Nosewheel steering in the PiperJet is accomplished using a direct
linkage system through the rudder pedals. No electrical or
hydraulic assists are required.
Nosewheel travels will be determined during flight tests, but
for now the travel in the POC test aircraft is 30 degrees left and
right. Piper test pilots reported light rudder pedal forces and
excellent response as the PiperJet POC was maneuvered with
confidence in the tight confines of the Vero Beach factory test
ramp for the first time.
The next major milestone in the Countdown to First Flight is
high speed taxi testing. During these tests, test pilots will
accelerate to speeds just below liftoff to check for basic runway
handling characteristics and elevator control authority. After
that, it's on to the excitement of the first flight with
performance verifications and handling characteristics testing to
follow in an extensive flight test program.
Though it shares certain design elements with the manufacturer's
Malibu/Meridian/Mirage line of cabin-class single-engine propeller
aircraft, the PiperJet is billed as the first "clean-sheet" design
to come from the Vero Beach, FL planemaker in a number of
years.
ANN's Daily Aero-Linx (05.04.24)
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